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RUDIMENTARY TREATISE
ON THE
CONSTRUCTION OF LOCKS.


London:
Printed by Levey, Robson, and Franklyn,
Great New Street and Fetter Lane.




RUDIMENTARY TREATISE
ON THE
CONSTRUCTION OF LOCKS.

Edited by

CHARLES TOMLINSON.


“Il n’y a point de machines plus communes que les serrures: elles sont
assez composées pour mériter le nom de _machine_; mais je ne sais s’il
y en a qui soient aussi peu connues par ceux qui les emploient. Il est
rare qu’on sache en quoi consiste la bonté d’une serrure, le degré de
sûreté qu’on peut s’en promettre. Leur extérieur est presque la seule
chose à quoi l’on s’arrête. Les usages importans auxquels elles sont
employées devraient cependant exciter la curiosité à les connaître, si
la curiosité était toujours excitée raisonnablement.”--M. DE RÉAUMUR,
“_Des Serrures de toutes les espèces_,” forming the fifth chapter of
M. Duhamel’s Treatise “_Art du Serrurier_,” in the “_Descriptions des
Arts et Metiers faites ou approuvées par Messieurs de l’Académie
Royale des Sciences_.”






London:
John Weale, 59 High Holborn.
MDCCCLIII.




  “There are no machines more common than locks: they are sufficiently
  complex to merit the name of _machine_; but I know of no others the
  structure of which is so little understood by those who use them. It
  is rare to find any one who knows wherein the goodness of a lock
  consists, or the degree of security that he can attach to it. The
  outside of a lock is usually all that attracts attention. Doubtless
  the important uses to which locks are applied would excite curiosity
  respecting their structure, if curiosity were always excited for
  worthy objects.”--M. DE RÉAUMUR.




PREFACE.


The reader is entitled to know the origin of the small work which he
holds in his hands.

In August 1852, being about to write a short article on Locks for a
Cyclopædia of Useful Arts, of which I am the editor, I consulted my
esteemed and lamented friend, the late Professor Cowper, of King’s
College, as to the desirability of explaining to the general reader the
defects of some of our English locks, which, previous to the celebrated
“lock controversy” of 1851, had borne a high character for skilful
construction, beauty of workmanship, and undoubted security. Professor
Cowper expressed his strong conviction that by exposing the defects of
our locks, the cause of mechanical science, as well as the public in
general, would be benefited; that if our locks were defective, inventors
would be stimulated to supply the defects, and the art of the locksmith
would be raised accordingly. He considered that Mr. Hobbs had made a
considerable step in advance in the constructive details of his art, not
only in having detected the weak points of some of our best English
locks, but also in having introduced two or three new locks, which
appeared to be more secure than any of those previously produced.
Professor Cowper gave me an introduction to Mr. Hobbs, who placed at my
disposal a variety of literary materials relating to the history and
construction of locks, and stated his intention at some future time of
bringing out a small book on the subject, if he could meet with a
publisher. I recommended him to offer the work to Mr. Weale, for
insertion in his series of Rudimentary Works. This was accordingly done,
and I was invited to prepare the work; but as my engagements did not
leave me sufficient leisure to write the book, I requested my friend Mr.
George Dodd to put the materials together, and to search for more. Mr.
Dodd acceded to my request; and having completed his part of the work, I
subjected it to a careful revision, and added various details which
seemed to be necessary to completeness, at least so far as the narrow
limits of a small rudimentary work would admit of completeness. The
manuscript was then sent to press: each sheet as it was received from
the printer was submitted to Mr. Hobbs, who read it with care, and made
his annotations and corrections thereon. Mr. Hobbs and I then had a
meeting, when the additions and corrections were read and discussed, and
admitted or rejected as the case might be. The sheet having been thus
corrected was sent to press.

It should also be stated that, during the progress of the work, Mr.
Weale, at my request, wrote to Messrs. Bramah, and also to Messrs.
Chubb, informing them that a Rudimentary Treatise on the Construction of
Locks was being prepared, and requesting them to state in writing what
alterations or improvements they had made in their locks since the date
of the Great Exhibition. The communications which we have received from
these celebrated firms are inserted _verbatim_, in their proper places,
in the present work.

Such is the mode in which this small volume has been prepared. I have
endeavoured to perform an editor’s duty conscientiously, without
entertaining the feeling of a partisan in the matter. My chief object in
superintending the production of this book (an object in which the
Publisher fully participates) is to advance the cause of mechanical
science, and to supply a deficiency in one of the most interesting
portions of its English literature.

  C. TOMLINSON.

  _Bedford Place, Ampthill Square,
  July 1853._




ADVERTISEMENT.


The first edition of this volume, though at the date of its appearance
co-ordinating with the state of knowledge of the period, and containing
matter well arranged and lucidly described--as must have been expected
from the reputation of its author--had, through the lapse of the few
intervening years, inevitably become somewhat behind the state of the
art of which it treats--one which is daily receiving the attentive
consideration of many skilful men, and occasional marked improvements.
Amongst those of later years none are more noteworthy than the locks
patented by Mr. Fenby, of Birmingham; of these an account, with accurate
illustrations, for which the drawings are supplied by the inventor, is
now added,--together with a brief essay upon the important but popularly
ill-understood subject of iron safes.

  ROBERT MALLET.

  _April, 1868._

In reference to Mr. Smyth’s letter, which is given at pp. 130, 131, that
gentleman is desirous to state that it was in consequence of the defects
there pointed out that Mr. Hobbs was enabled to pick the Bramah lock
operated upon, which had been manufactured forty years previously, when
the sliders were made of iron instead of steel as they now are, and yet,
notwithstanding that and the other defects pointed out, it took Mr.
Hobbs sixteen days to pick it. In proof of the security of the Bramah
lock, Mr. Smyth mentions that Mr. Hobbs’s best workman failed in picking
an ordinary 3-inch Bramah box lock; and that a person in the employ of
Messrs. Johnson and Ravey, of Conduit Street, failed also in his attempt
to pick a 6-inch cellar-door lock, though he had the lock in his
possession for twelve months, employing his evenings in making
instruments and trying to pick it. Mr. Smyth contradicts the statement
made at page 128, that the new lock was removed from the window through
any fear of its being opened. On the contrary, it was put up especially
to afford an opportunity for Mr. Hobbs to make, if he thought fit,
another trial, and it remained in the window four months. The sole cause
of its removal was to stop the impertinent applications of men and boys,
which interfered too much with the general business of the firm.




CONTENTS.


  CHAP.                                                             PAGE

     I. On Locks and Lock-literature                                   1

    II. Ancient Locks: Grecian, Roman, Egyptian                        8

   III. Lock classification. The Puzzle-Lock and the Dial-Lock        16

    IV. Warded Locks, with their varied appendages                    27

     V. On Tumbler or Lever Locks                                     43

    VI. The Bramah Lock                                               64

   VII. American Locks                                                82

  VIII. The Lock Controversy: previous to the date of the Great
        Exhibition                                                   102

    IX. The Lock Controversy: during and since the time of the
        Great Exhibition                                             115

     X. Effects of the Great Exhibition of 1851 in improving
        English Locks                                                140

    XI. The Lock and Key Manufacture                                 154

   XII. English Patents for Locks. Aubin’s Lock Trophy. Conclusion   164

  APPENDIX.

  XIII. On an Improved Construction of Lock and Key: Fenby’s Adytic
        Lock                                                         176

   XIV. Fenby’s Stop Lock                                            193

    XV. Note upon Iron Safes                                         201




  ON THE
  CONSTRUCTION OF LOCKS.




CHAPTER I.

ON LOCKS AND LOCK-LITERATURE.


The manufacture of locks, and a consideration of the mechanical
principles involved in their construction and security, have never yet
been treated with any degree of fulness in an English work. Lock-making
has occupied a large amount of ingenuity, and lock-patents have been
obtained in considerable number, though not always, we are satisfied,
with a commensurate return for the expense incurred,--but
lock-philosophy (if so it may be designated) has not been largely
attended to.

And yet it may safely be said that much which is both mechanically and
commercially important is comprised in a lock. Every improvement in the
manufacture of iron, steel, and brass--that is, in the tool-making and
machine-making processes--may be made to reflect its light on the
lock-manufacture; the stamping, the casting, the planing, the slotting,
the screw-cutting, the polishing of metals,--all, in proportion as they
are improved, impart some of their aid to the lock-maker. Then, in the
finer kinds of locks, the works are so delicate as to approach to the
nicety of clockwork; thereby combining the manipulative skill of a
talented artisan with the rougher mechanical work of the smith. The
principles of mechanical science are also appreciated by many
lock-makers. The lever, the inclined plane, the eccentric, the cam, the
screw, the wheel and pinion, the ratchet, the spring,--all are brought
to bear on the internal mechanism of locks, frequently in many novel
combinations.

The commercial importance of locks--though of course never seriously
questioned when once fairly brought before one’s attention--has been
recently rendered so apparent as to have risen to the position of a
public topic. If a strong room, containing gold and silver, notes and
bills, books and papers--if such a room be necessarily shielded from
intrusion, it becomes no less necessary that the shield should be really
worthy of its name, trusty and reliable: a good lock is here nearly as
indispensable as a faithful cashier. And without dwelling on such an
auriferous picture as a room fall of gold, we shall find ample proof of
the commercial importance of lock-making in the ordinary circumstances
by which we are every day surrounded. Until the world becomes an honest
world, or until the honest people bear a larger ratio than at present to
the dishonest, the whole of our movables are, more or less, at the mercy
of our neighbours. Houses, rooms, vaults, cellars, cabinets, cupboards,
caskets, desks, chests, boxes, caddies,--all, with the contents of each,
ring the changes between _meum_ and _tuum_ pretty much according to the
security of the locks by which they are guarded.

A commercial, and in some respects a social, doubt has been started
within the last year or two, whether or not it is right to discuss so
openly the security or insecurity of locks. Many well-meaning persons
suppose that the discussion respecting the means for baffling the
supposed safety of locks offers a premium for dishonesty, by shewing
others how to be dishonest. This is a fallacy. Rogues are very keen in
their profession, and know already much more than we can teach them
respecting their several kinds of roguery. Rogues knew a good deal about
lock-picking long before locksmiths discussed it among themselves, as
they have lately done. If a lock--let it have been made in whatever
country, or by whatever maker--is not so inviolable as it has hitherto
been deemed to be, surely it is to the interest of _honest_ persons to
know this fact, because the _dishonest_ are tolerably certain to be the
first to apply the knowledge practically; and the spread of the
knowledge is necessary to give fair play to those who might suffer by
ignorance. It cannot be too earnestly urged, that an acquaintance with
real facts will, in the end, be better for all parties. Some time ago,
when the reading public was alarmed at being told how London milk is
adulterated, timid persons deprecated the exposure, on the plea that it
would give instructions in the art of adulterating milk; a vain
fear--milkmen knew all about it before, whether they practised it or
not; and the exposure only taught purchasers the necessity of a little
scrutiny and caution, leaving them to obey this necessity or not, as
they pleased. So likewise in respect to bread, sugar, coffee, tea, wine,
beer, spirits, vinegar, cheap silks, cheap woollens--all such articles
as are susceptible of debasement by admixture with cheaper
substances--much more good than harm is effected by stating candidly and
scientifically the various methods by which such debasement has been, or
can be produced. The unscrupulous have the command of much of this kind
of knowledge without our aid; and there is moral and commercial justice
in placing on their guard those who might possibly suffer therefrom. We
employ these stray expressions concerning adulteration, debasement,
roguery, and so forth, simply as a mode of illustrating a principle--the
advantage of publicity. In respect to lock-making, there can scarcely be
such a thing as dishonesty of intention: the inventor produces a lock
which he honestly thinks will possess such and such qualities; and he
declares his belief to the world. If others differ from him in opinion
concerning those qualities, it is open to them to say so; and the
discussion, truthfully conducted, must lead to public advantage: the
discussion stimulates curiosity, and the curiosity stimulates
invention. Nothing but a partial and limited view of the question could
lead to the opinion that harm can result: if there be harm, it will be
much more than counterbalanced by good.

The literature of lock-making is, as we have implied, very scanty, both
in England and America. The French and Germans, though far below our
level as lock-makers, are very superior to us in their descriptions of
the construction and manufacture of locks. Take, for instance, the
French treatise published more than eighty years ago by the _Académie
des Sciences_, and forming part of a folio series of manufacturing
treatises, illustrated very fully by engravings. It is worth while to
examine this work, to see how minutely and faithfully the writers of
such treatises performed their task nearly a century ago. The _Art du
Serrurier_, with the distinguished name of M. Duhamel du Monceau as the
author or editor, was published in 1767. It occupies 290 folio pages,
and is illustrated by 42 folio plates. The first chapter gives us an
introduction and general principles, in which the choice and
manipulation of materials are touched upon; the different qualities of
iron and steel; and the processes of forging, founding, welding,
stamping, filing, polishing, &c. In the copper-plates representing these
smiths’ operations and the tools employed,[1] there is a smithy, with
about a dozen smiths engaged in all these various occupations, with
stockings down, and a due amount of workshop slovenliness. The next
chapter takes us into what may perhaps be called “smith’s work in
general,” or at least it treats of the manufacture of various kinds of
ironmongery for doors, windows, and house-fittings generally. Then the
third chapter treats of “smith’s work which serves for the security of
houses,” consisting of railings, palings, bars, and gates of various
kinds--such at least as are made of iron. In chapter four we have a
notice of such kinds of smith’s work as relate to the fastenings for
doors, windows, closets, chests, &c.; such as hinges, hasps, latches,
bolts, and other contrivances less complex than an actual lock. This
brings us, by a natural transition, to locks in general, which form the
subject of chapter five, to which is attached the illustrious name of M.
de Réaumur as the author. Here are given a hundred folio pages of
description, illustrated by twenty folio plates relating to locks,
lock-making, and locksmiths. The sixth chapter relates to the iron-work
of carriages, or the labours of the coachsmiths; while chapter seven, to
wind up the work, relates to bell-hanging.

  [1] It is worthy of remark, that the tools described are the same as
  those which are used by the locksmith at the present day; shewing how
  little improvement has been made in the means of producing locks.

That chapter of the work which has reference to locks is the only one
with which we have to do here. It is arranged in a systematic manner,
beginning with the simpler locks, without wards or tumblers, and
proceeding thence to others of more complex construction. The period at
which the work was written was too early to lead us to expect to find a
tumbler-lock described and delineated: there are, however, numerous
examples of single tumbler-locks, many of them of great ingenuity. The
use of multiple bolts, that is, of many bolts shot at once by one action
of the key, seems to have been familiar enough to the locksmiths of
those days. One lock represented is remarkable; it is attached to a
strong and ponderous coffer or chest. The chest is open; and the whole
under or inner surface of the cover is seen to be occupied by a lock of
intricate construction; there are no less than twelve bolts, three on
each long side, one on each short side, and one in each corner; these
bolts are so placed as to catch under a projecting rim fixed round the
top of the coffer. The collection of keys, exhibited on a separate
plate, is remarkable for the great variety of forms given to them. We
shall by and by copy some of the drawings of this curious work.

It was to be expected that in the _Encyclopédie Méthodique_, published
in the same country and in the same century, the locksmith’s art would
be treated at some such length as in the work just described. Among the
two hundred volumes of which the _Cyclopédie_ consists, several are
devoted to arts and manufactures; and one of them contains the article
in question. It occupies 168 quarto pages, and is illustrated by 35
copper-plate engravings, shewing in detail not only the parts of various
locks, but the tools used by the lockmaker. It is proper, however, to
remark, that much of the letterpress and many of the plates relate to
smith’s work generally, and not exclusively to lock-work; the French
name _serrurerie_ being applied not only to lock-making, but to most of
the smith’s work required in dwelling-houses. This affords, indeed, a
striking illustration of the fact, that until lately a lock-maker has
been regarded rather as a smith than as a machinist, rather as a forger
and filer of pieces of iron, than as a fabricator of delicate mechanism.
One of the most curious features in this treatise is a vocabulary,
containing, in alphabetical arrangement, a minute account of all the
French technical terms employed in the locksmith’s art. This vocabulary
alone occupies 38 quarto pages.

The Germans, like the French, bestow great attention on their treatises
relating to the manufacturing arts. Some of these are, indeed, worked up
to a degree of minuteness which would seem superfluous, where little
distinction is drawn between the importance of fundamental principles
and that of mere technical details. Locks have had their due share. The
article on locks in Prechtl’s _Technological Encyclopædia_ written by
Karmarsch, and published in 1842, occupies about 140 pages. Locks are
very minutely classified by the author, according to their purposes and
their modes of action, and are illustrated by many plates. One of his
classifications is into _German_, _French_, and _Bastard_ locks,
referring in part to the extent to which the key turns round in the
lock; and the last of the three having an intermediate character between
the other two. After treating of the ordinary warded locks, he comes to
the combination principle; and it is profitable here to notice, how well
the works of our machinists are understood on the continent, when they
have any thing to recommend them; there are a dozen closely printed
pages devoted to a minute description of Bramah’s invention, with all
the separate parts illustrated by copper-plate engravings. After this
comes a more general account of the details and manufacture of locks,
similarly illustrated by engravings.

Whatever may be the merits of the different articles relating to locks
in the various English cyclopædias, there are none approaching in length
to the article in Prechtl’s work. But when we consider that Prechtl
devotes twenty large volumes to technological or manufacturing subjects,
he is of course able to devote a larger space to each article than is
given in English works. Both in England and in America, men are more
disposed to do the work than to describe it when done. In the
_Encyclopædia Britannica_, in Rees’ _Cyclopædia_, in Hebert’s
_Engineers’ and Mechanics’ Cyclopædia_, in the _Encyclopædia
Metropolitana_, in the _Penny Cyclopædia_, and in other similar works,
locks are described as well as can be expected within the limits
assigned to the articles. Mr. Bramah’s essay on locks, and on his own
lock in particular, is one of the few English pamphlets devoted
expressly to this subject. An excerpt from the proceedings of the
Institute of Civil Engineers, in 1851, gives an interesting paper on
locks by Mr. Chubb; and shorter reports of papers and lectures have been
published in various ways. Perhaps the best account of locks which we
have, considering the limited space within which a great deal of
information is given in a very clear style, is that contained in Mr.
Tomlinson’s _Cyclopædia of Useful Arts_.




CHAPTER II.

ANCIENT LOCKS: GRECIAN, ROMAN, EGYPTIAN.


Locks and door-fastenings have not, until modern times, been susceptible
of any classified arrangement according to their principles of
construction. They have been too simple to require it, and too little
varied to permit it. That some such fastenings must be employed wherever
doors of any kind are used is sufficiently apparent; and there is a
little (though only a little) information obtainable, which shews the
nature of the fastenings adopted in early times. The bolt, the hasp, the
chain, the bar, the latch, the lock, all were known, in one or other of
their various forms, in those ages which we are accustomed to consider
classical. Travellers, generally speaking, do not descend to locks, or
rather they do not think about them; otherwise they might have collected
much that would have been novel and applicable to the present work; and,
indeed, there is some ground for the assertion, that a notice of the
door-fastenings of all nations would reveal to us something of the
social and domestic habits of various members of the great human family.
Be this as it may, however, we may profitably make a little inquiry into
the locks of ancient times.

In the volumes of Lardner’s _Cyclopædia_ relating to the “Manners and
Customs of the ancient Greeks and Romans,” we do not find any mention of
the kinds of locks used by those nations; but the author, while
describing the houses, says:--“Doors turned anciently upon large pivots
in the centre, let into sockets in the lintel and threshold, so that one
of the sides opened inwards, the other outwards; and Plutarch gives the
following curious reason why persons were to knock and alarm the
porter, viz. lest the visitor entering unawares should surprise the
mistress or daughter of the family busy or undressed, or servants under
correction, or the maids quarreling.” As the visitors had thus the power
(if permitted so to do) to open the outer door of a house, it would
appear that very little in the nature of a lock was employed under
ordinary circumstances, unless indeed it were a mere latch. In respect
to Roman houses it is stated, that “the doors revolved upon pivots,
which worked in a socket below, and were fastened by bolts which hung
from chains.” There is no mention of locks here. Mr. St. John, in his
work on the same subject, says: “The street-door of a Grecian house,
usually, when single, opened outwards; but when there were folding-doors
they opened inwards, as with us. In the former case it was customary,
when any one happened to be going forth, to knock, or call, or ring a
bell, in order to warn passengers to make way.” After describing the
various kinds of wood of which the doors were made, he proceeds: “The
doors at first were fastened by long bars passing into the wall on both
sides; and by degrees smaller bolts, hasps, latches, and locks and keys,
succeeded. For example, the outer door of the thalamos in Homer was
secured by a silver hasp, and a leathern thong passed round the handle,
and tied, perhaps, in a curious knot.”

Mr. Yates, in a learned article on this subject in Smith’s _Dictionary
of Greek and Roman Antiquities_, collects numerous details scattered
through various early writers. We will string together a few of these
details, so far as they have any relation to the fastenings of doors.
The outer door of a Roman house was generally called _janua_; whereas
the inner doors were called _ostia_. The doorway, when complete,
consisted of four indispensable parts--the threshold or sill, the
lintel, and the two jambs. The threshold, on which the feet trod, was
often regarded with a kind of superstitious reverence; the lintel, which
crossed the doorway at the top, having a considerable superincumbent
weight to bear, was usually made of one piece of timber or stone of
great strength; the jambs, or side uprights, were also made in one
piece each. The doorway, in every building of the least importance,
contained two doors folding together; even the internal doors had their
bivalve construction. But in every case each of the two valves was wide
enough to allow persons to pass through without opening the other; in
some cases even each valve was double, so as to fold like our
window-shutters. These doors, or valves, were not hinged to the
side-posts, as with us, but were, as has already been stated, pivoted to
the lintel above and the threshold below. The fastening usually
consisted of a bolt placed at the base of each valve or half-door, so as
to admit of being pushed into a socket made in the sill to receive it.
The doorways in some of the houses at Pompeii still shew two holes in
the sill, corresponding to the bolts in the two valves. At night, the
front door of the house was further secured by means of a wooden and
sometimes an iron bar placed across it, and inserted into sockets on
each side of the doorway; hence it was necessary to remove the bar in
order to open the door. Chamber-doors were often secured in the same
manner. In the _Odyssey_ there is mention of a contrivance (adverted to
by Mr. St. John) for bolting or unbolting a door from the outside; it
consisted of a leather thong inserted through a hole in the door, and by
means of a loop, ring, or hook, capable of taking hold of the bolt so as
to move it in the manner required. We have here evidently the elements
of a more complete mechanism; for the bolt was a rude lock in the same
degree that the thong was a rude key. That the Romans afterwards had
real locks and keys is clear; for the keys found at Herculaneum and
Pompeii, and those attached to rings, prove that a kind of warded lock
must have been well known.[2] There are the remains of a tomb at
Pompeii, the door of which is made of a single piece of marble,
including the pivots, which were encased in bronze, and turned in
sockets of the same metal; it is three feet high, two feet nine inches
wide, and four and a quarter inches thick; it is cut in front to
resemble panels, and thus approaches nearer in appearance to a modern
wooden door; and it was fastened by some kind of lock, traces of which
still remain.

  [2] An examination of the Roman keys in the British Museum
  sufficiently attests this fact.

The same facts frequently become more clear when described in different
words by different writers. We shall make use of this circumstance. Mr.
Donaldson, in his _Essay on Ancient Doorways_, presents us with details
which illustrate many of the foregoing remarks. “Homer describes the
treasures and other valuable objects (mentioned in the _Odyssey_) as
being kept in the citadel, secured merely by a cord intricately knotted.
This, of course, was soon found to be a very insufficient protection,
and therefore a wooden bar was adopted inside the doors of houses, to
which it was attached by an iron latch, fastened or removed by a key
adapted to it; this key was easily applied from within; but in order to
get at it from without, a large hole was made in the door, allowing the
introduction of the hand, so as to reach the latch and apply the key.
The lock called the Lacedæmonian, much celebrated by ancient writers,
was invented subsequently; it was especially fitted for the inner
chambers of houses, the bar fastenings continuing to be employed for
closing the outer doors of dwellings and the entrance-gates to cities.
The Lacedæmonian lock did not require a hole to be made in the door, for
it consisted of a bolt placed on that side of the entrance-door which
opened, and on the inside of a chamber-door. When a person who was
outside wished to enter, it was necessary for him to insert the key in a
little hole and to raise the bolt; and in time this species of fastening
was improved by the insertion of the bolt in an iron frame or rim
permanently attached to the door by a chain, and fastening the door by
the insertion of the hasp, through the eye of which was forced the bolt
inside the lock by applying the key.” After quoting a Latin sentence
from Varro in elucidation of his subject, Mr. Donaldson proceeds to
observe, that for the most part the locks of the ancients were different
in principle from those of modern days, not being inserted or mortised
into the doors, nor even attached except by a chain; they were, in fact,
padlocks.

One of the passages in the _Odyssey_ alluding to the primitive mode of
fastening the valves or folding-doors of a house runs thus:--

  “Whilst to his couch himself the prince addressed,
   The duteous nurse received the purple vest:
   The purple vest with decent care disposed,
   The silver ring she pulled, the door reclosed;
   The bolt, obedient to the silken cord,
   To the strong staple’s inmost depth restored,
   Secured the valves.”

Most of the other great nations of antiquity resembled either the
Egyptians or the Greeks and Romans, more or less closely, in their
domestic and domiciliary arrangements; or, at any rate, so far as such
humble matters as locks and keys are concerned, we need not seek far
from those nations for examples. The Nineveh and other Assyrian
explorations have, however, revealed many curious and unexpected facts;
from the temples and the palaces we may by and by penetrate into the
houses and rooms of the citizens sufficiently to know how their doors
were fastened. In the mean time ancient Egypt awaits our notice.

Sir J. Gardner Wilkinson, in his _Manners and Customs of the Ancient
Egyptians_, gives the following information concerning the doors and
door-fastenings of that remarkable people, on the authority of models,
sculptures, and paintings, still existing. The doors were frequently
stained so as to imitate foreign and rare woods. They were either of one
or two valves, turning on pieces of metal, and were secured within by a
bar or by bolts. Some of these bronze pins have been discovered in the
tombs of Thebes; they were fastened to the wood with nails of the same
metal, the round heads of which served also as ornaments. In the stone
lintels and floors behind the thresholds of the tombs and temples are
still frequently to be seen the holes in which the pivot-pins turned, as
well as those of the bolts and bars, and the recess for receiving the
opened valves. The folding-doors had bolts in the centre, sometimes
above as well as below; a bar was placed across from one wall to the
other.

In many of the ancient Egyptian doors there were wooden locks fixed so
as to fasten across the centre at the junction where the two folds of
the door met. It is difficult, by mere inspection of the bas-reliefs and
paintings, to decide whether these locks were opened by a key, or were
merely drawn backwards and forwards like a bolt; but if they were really
locks, it is probable that they were on the same principle as the
Egyptian lock still in use. For greater security, these modern locks are
occasionally sealed with a mass of clay; and there is satisfactory
evidence that the same custom was frequently observed among the ancient
inhabitants of that country. Sir J. G. Wilkinson gives a representation
of an iron key, now in his possession, which he procured among the tombs
at Thebes, and which looks very much like a modern burglar’s picklock.
In relation to keys generally, and after mentioning the use of bronze
for their manufacture, he says: “At a later period, when iron came into
general use, keys were made of that metal, and consisted of a straight
shank about five inches in length, and a bar at right angles with it, on
which were three or more projecting teeth. The ring at the upper
extremity was intended for the same purpose as that of our modern keys;
but we are ignorant of the exact time when they were brought into use;
and the first invention of locks distinct from both is equally
uncertain; nor do I know of any positive mention of a key, which, like
our own, could be taken out of the lock, previous to the year 1336
before our era; and this is stated to have been used to fasten the door
of the summer parlour of Eglon, the king of Moab. The description here
adverted to is that contained in Judges iii. 23-25: ‘Ehud went forth
through the porch, and shut the doors of the parlour upon him, and
locked them ... his servants ... took a key, and opened them.’”

The curious and ingenious wooden lock of ancient Egypt is still in use
in Egypt and Turkey. In Eton’s _Survey of the Turkish Empire_, published
towards the close of the last century, the locks then and there in use
are thus described: “Nothing can be more clumsy than the door-locks in
Turkey; but their mechanism to prevent picking is admirable. It is a
curious thing to see wooden locks upon iron doors, particularly in Asia,
and on their caravanserais and other great buildings, as well as upon
house-doors. The key goes into the back part of the bolt, and is
composed of a square stick with five or six iron or wooden pins, about
half an inch long, towards the end of it, placed at irregular distances,
and answering to holes in the upper part of the bolt, which is pierced
with a square hole to receive the key. The key being put in as far as it
will go, is then lifted up; and the pins, entering the corresponding
holes, raise other pins which had dropped into these holes from the part
of the lock immediately above, and which have heads to prevent them
falling lower than is necessary. The bolt, being thus freed from the
upper pins, is drawn back by means of the key; the key is then lowered,
and may be drawn out of the bolt. To lock it again, the bolt is only
pushed in, and the upper pins fall into the holes in the bolt by their
own weight.” Mr. Eton, probably seeing how well the tumbler-principle is
here understood, says: “This idea might be improved on; but the Turks
never think of improving.” The locks on the doors of modern houses in
Cairo seem to be of this long-established form, except where iron locks
have been imported from Europe.

A letter was inserted in the _Journal of Design_ for July 1850 from Mr.
W. C. Trevelyan; in which, after adverting to the Egyptian lock, he
says: “It is remarkable that the locks which have been in use in the
Faröe Islands, probably for centuries, are identical in their
construction with the Egyptian. They are, lock and key, in all their
parts made of _wood_; of which material, if I mistake not, they have
also been found in Egyptian catacombs; and so identical with the
Faröese in structure and appearance, that it would not be easy to
distinguish one from the other.”

[Illustration: fig. 1.]

[Illustration: fig. 2.]

[Illustration: fig. 3.]

[Illustration: fig. 4.]

The construction of this remarkable Egyptian or pin-lock will be
understood from the accompanying engravings. The quadrangular portion,
_a a_ fig. 1, is the case of the lock, screwed or otherwise fastened to
the door, having a wooden bolt, _b b_, passing horizontally through a
cavity in it. In the part of the case above the bolt are several small
cells containing headed pins, arranged in any desired form; and in the
top of the bolt itself are an equal number of holes similarly arranged.
The effect of this arrangement is such that, when brought into the right
positions, the lower ends of the headed pins drop into the corresponding
holes in the bolt, thereby fastening the bolt in the lock-case. A large
hollow, or cavity, is made at the exposed end of the bolt, the cavity
extending as far as and beyond the holes occupied by the pins. The key
consists of a piece of wood (shewn in two positions, figs. 3 and 4,)
having pins arranged like those in the lock, and projecting upwards just
to a sufficient distance to reach the upper surface of the bolt. This
being the arrangement, whenever the key is introduced and pressed
upwards, its pins exactly fill the holes in the bolt, and by so doing
dislodge those which had fallen from the upper part of the case. The
bolt may, under these circumstances, be withdrawn (as shewn in fig. 2),
leaving the headed pins elevated in their cells, instead of occupying
the position shewn by the dotted lines in fig. 1. The cavity in the bolt
must of course be high enough to receive the thickness of the key, and
also the length of the pins protruding from the key.

This primitive lock comprises many of the best features of the tumbler
or lever-locks of later days, as will be seen in a future chapter. There
will also be opportunities of shewing how the pin-action has been
applied in other ways in some of the modern locks.




CHAPTER III.

LOCK CLASSIFICATION. THE PUZZLE-LOCK AND THE DIAL-LOCK.


In approaching the subject of modern locks it becomes necessary to
decide upon some method of treating the widely-scattered and diverse
materials which are presented to our notice. One plan would be to trace
the subject chronologically, by describing, in the order of their
invention, the most important locks which have been presented to public
notice. But this would be attended with some disadvantages: the peculiar
characters of the several locks would not be brought out with sufficient
distinctness; and the result, so far as the reader is concerned, would
rather tend to confusion than to a clear appreciation of the subject.
There are more advantages belonging to a classification of locks under
certain headings, according to some marked peculiarities in their modes
of action. This is a convenient plan, but it is not an easy one to put
in execution; for inventors have not sought to place their locks in any
particular class, but rather to call attention to their merits.
Moreover, many locks embody two or three distinct principles so
equally, that it will often be difficult to decide in which class to
place them. This, nevertheless, may be done with an approach to
correctness. It is necessary first, however, to explain certain
technical terms by which locks are distinguished one from another.

Locks, in truth, admit of an immense variety, which, however important
to be known to locksmiths, carpenters, and others employed on them, need
only be glanced at very cursorily by the general reader. Some locks are
named according to the purposes to which they are to be applied; others
according to their shape, or the principles of their construction. In
the first place, there is the distinction between _in-door_ and
_out-door_ locks. Of in-door locks, one principal kind is the
_draw-back_ lock, for street-doors, in which the bolt is capable of
maintaining any one of three positions: it may be locked by the key, or
left half-way out by the pressure of a spring, or be drawn back by a
handle. In the first position, it can only be withdrawn by the key; in
the second, it closes the door, but can easily be withdrawn by the
handle; and in the third, it leaves the door unfastened. If these locks
are made of iron and carefully finished, they are further called
_iron-rim_; but if made of wood, suitable for back-doors and inferior
purposes, they are _spring-stock_. For the doors of rooms, there are the
_iron-rim_, the _brass-case_, and the _mortise_ lock; the second
supplants the first, and the third the second, as we advance in the
elegance of the door-fittings. Other designations for room-locks depend
on the number of the bolts: thus, if there be only one bolt, it is a
_dead lock_ or _closet lock_; if there be a second bolt, urged by a
spring and drawn back by a handle, it is a _two-bolt lock_; and if there
be also a third, a private bolt acting only on one side of the door, it
is a _three-bolt lock_. Again, according to the kind of handle employed,
it may be a _knob lock_ or a _ring lock_. According to which edge of the
door it is to be fixed, it becomes a _right-hand_ or a _left-hand_ lock.
If the wards of the lock are of somewhat superior quality, and bend
round nearly to a circle, the lock is _one-ward round_, _two-ward
round_, and so forth. If the lock has no wards at all, it is _plain_; if
the wards are of common character, they are often called _wheels_, and
then the lock becomes _one-wheel_, _two-wheel_, &c. Sometimes the lock
is named from certain fancied resemblances in the shape of the ward, as
the L-_ward_, T-_ward_, or Z-_ward_. If the wards are cast in brass,
instead of being made of slips of iron or copper, the lock is termed
_solid ward_.

Of the numerous but smaller varieties known by the collective name of
_cabinet locks_, there are the _cupboard_, the _bookcase_, the _desk_,
the _portable desk_, the _table_, the _drawer_, the _box_, the _caddy_,
the _chest_, the _carpet-bag_, and many other locks. All these locks are
further called _straight_, when the plate is to be screwed flat against
the wood-work; _cut_, when the wood is to be so cut away as to let in
the lock flush with the surface; and _mortise_, when a cavity is
excavated in the edge of the door for the reception of the lock.

Out-door locks are usually _wooden stock locks_, for stables, gates,
&c.; comprising many varieties of _Banbury_, _bastard_, _fine_, &c.
There are D _locks_ and P _locks_, for gates, designated from their
shapes; and there are the numerous kinds of _padlocks_.

The above terms are employed chiefly between the makers of the locks and
the persons who fix them in their places; but there are other terms and
names, more familiarly known, which will come under notice in future
pages.

It is scarcely worth while to descant upon the “middle age” of
lock-making--to impart to the subject so much of dignity as to be
susceptible of regular historical treatment. True, we know that _wards_
were employed before _tumblers_ (unless, indeed, the pins of the
Egyptian lock be considered as tumblers--a character to which they
present considerable claim), and that wards may be taken as the
representative of the medieval period of lock-making; but it may be more
profitable to proceed in our notice of the different kinds of locks in
an order which will in itself partake somewhat of the historical
character.

Apart from all the warded and tumbler locks are the very curious
_puzzle_ or _letter-locks_; a construction which we propose to dismiss
out of hand in the present chapter, before treating of those which have
more commercial importance.

The puzzle-lock is generally in the form of a padlock, which is opened
and closed without the use of a key, and which has certain difficulties
thrown in the way of its being opened by any one who is not in the
secret of the person who closed it. It is, in fact, one of the locks in
which the doctrine of permutation is made to contribute to the means of
security. The key to open it is a _mnemonic_ or _mental_ one, instead of
one of steel or iron. Two centuries ago, the puzzle-lock attracted far
more attention than any other. It has always certain movable parts, the
movement of which constitutes the enigma. Some of these very curious and
out-of-the-way locks are so formed as to receive the name of
_dial-locks_; but the chief among them are _ring-locks_--a name the
meaning of which will be presently understood.

The puzzle or letter-lock of the ring kind, then, consists essentially
of a spindle; a barrel, encompassing the spindle; two end-pieces, to
keep the spindle and barrel in their places; and the shackle, hinged to
one of these end-pieces. To unfasten the lock, one of the end-pieces
must be drawn out a little, to allow the shackle or horse-shoe to be
turned on its hinge; and the question arises, therefore, how this
end-piece is to be acted upon. This is effected in a very ingenious way:
there are four studs or projections in a row on the spindle, and as the
spindle fits pretty closely in the barrel, the former cannot be drawn
out of the latter unless there be a groove in the interior of the
barrel, as a counterpart to the studs on the exterior of the spindle;
four rings fit on the barrel, on the interior of each of which there is
a groove; and unless all these four grooves coincide in direction, and
even lie in the same plane as the groove in the barrel, the studs will
not be able to pass, and the spindle cannot be drawn out. Each ring may
be easily made to work round the barrel by means of the fingers, and to
maintain any position which may be given to it. There are outer rings,
one over each of the rings just described, with the letters of the
alphabet (or a considerable number of them) inscribed on each; and these
outer rings, by means of notches on the inside, govern the movements of
the inner rings.

The action is, therefore, as follows: when the padlock is to be locked,
the rings are so adjusted that all the grooves shall be in a right line;
the spindle is thrust in, the end-piece is fixed on, and the shackle is
shut down. The padlock is now fastened; but a reverse order of
proceeding would as easily open it again, and therefore the “safety” or
“puzzle” principle is brought into requisition. The outer rings are
moved with the finger, so as to throw the various interior grooves out
of a right line, and thus prevent the withdrawal of the spindle. As each
ring may be turned round through a large or a small arc, and all turned
in different degrees, the variations of relative position may be almost
infinite. The letters on the outer rings are to assist the owner to
remember the particular combination which he had adopted in the act of
locking; for no other combination than this will suffice to open the
lock. There may, for instance, be the four letters L O C K in a line,
which line is brought to coincide with two notches or marks at the ends
of the apparatus; and until all the four outer rings are again brought
into such relative position as to place the letters in a line, the lock
cannot be opened.

There are many allusions to locks, apparently belonging to the letter or
puzzle principle, in authors who flourished two or three centuries ago.
Thus, in Beaumont and Fletcher’s play of the _Noble Gentleman_, written
in the early part of the seventeenth century, one of the characters
speaks of

  “A cap-case for your linen and your plate,
   With a strange lock that opens with A·M·E·N.”

And in some verses by Carew, written about the same time, there is
an analogy drawn, in which one of the things compared is--

                                         “A lock
  That goes with letters; for till every one be known,
  The lock’s as fast as if you had found none.”

In the _Memorabilia_ of Vanhagen von Ense, written about the middle of
the seventeenth century, a commendatory notice is given of a
letter-lock, or combination-lock, invented by M. Regnier, Director of
the _Musée d’Artillerie_ at Paris. “Regnier,” we are told, “was a man of
some invention, and had taken out a patent for a sort of lock, which
made some noise at the time. Every body praised his invention, and
bought his locks. These consisted of broad steel rings, four, five, or
eight deep, upon each of which the alphabet was engraved; these turned
round on a cylinder of steel, and only separated when the letters
forming a particular word were in a straight line with one another. The
word was selected from among a thousand, and the choice was the secret
of the purchaser. Any one not knowing the word might turn the ring round
for years without succeeding in finding the right one. The workmanship
was excellent, and Regnier was prouder of this than of the invention
itself. The latter point might be contested. I had a vague recollection
of having seen something of the sort before; but when I ventured to say
so, my suspicions were treated with scorn and indignation, and I was not
able to prove my assertion; but many years afterwards, when a book,
which as a boy I had often diligently read, fell into my hands,
Regnier’s lock was suddenly displayed. The book was called _Silvestri a
Petrasancta Symbola Heroica_, printed at Amsterdam in 1682. There was an
explanation at p. 254, attached to a picture; these were the
words:--_Honorius de Bellis, serulæ innexæ orbibus volubilibus ac
literatis circumscripsit hoc lemma--Sorte aut labore_.[3] However,
neither luck nor labour would have done much more towards discovering
the secret of opening Regnier’s locks, from the variety of their
combinations; and their security seemed so great, that the couriers’
despatch-boxes were generally fastened with them.”

  [3] “Honorius de Bellis wrote this inscription,--_By chance or by
  labour_,--round a lock composed of revolving rings graven with
  letters.”

This curious extract, which was brought forward by Mr. Chubb, in a paper
on locks and keys (read before the Institution of Civil Engineers in
1850), seems to take away the credit from one (Regnier) with whose name
the letter-lock has been most intimately associated. We shall presently
explain, however, what it was that Regnier effected towards perfecting
the letter-lock. In the meantime it may be interesting to note that the
British Museum contains a copy of the work mentioned by Vanhagen. At the
page indicated there is an engraving (a fac-simile of which is given in
fig. 5) containing a drawing of a veritable puzzle or letter-lock; the
lock consists of a cylinder or barrel, on which seven rings work; each
of these rings is inscribed with letters, and the ends of the cylinder
are grasped by a kind of shackle.

[Illustration: fig. 5. Puzzle-lock of the seventeenth century.]

It was a natural result of the arrangement of the letter-lock, as
invented (conjecturally) by Cardan, that only one particular word or
cipher or key could be used in each lock; and it was to increase the
puzzle-power of the lock that Regnier doubled all the rings, making
each pair concentric, and enabling the user to vary the cipher at
pleasure.

The principle of the letter-lock, when applied to doors, requires that
sort of modification which renders it what is termed a _dial-lock_.
There are to such a lock one or more dials, with a series of letters or
figures stamped on them; there is to each dial a hand or pointer
connected by a spindle with a wheel inside the lock; on the wheel is a
notch which has to be brought to a certain position before the bolt can
be moved. There are false notches, to add to the difficulty of finding
the true notch in each wheel. To adjust the notches to their proper
position, a nut on the back of the wheel is loosened, and the pointer is
set at any letter or figure chosen by the user. The pointers and the
dials perform the part of the outer rings, the wheels that of the inner
rings; and it is easy to see that the same leading features prevail in
the two kinds of lock, however they may differ in detail.

These dial-locks have not been numerous; they require wheel and pinion
work within the body of the lock, which gives delicacy and complication
to the mechanism. The letter padlock, be its merits great or small, is
strong and durable, not liable to get out of order; and in so far as it
requires no key or key-hole, it occupies rather a special position among
locks. One of our great “merchant-princes” has been a letter-lock
inventor, as the following will shew.

Early in 1852, Mr. William Brown, the distinguished member for South
Lancashire, read a paper before the Architectural and Archæological
Society of Liverpool, of much interest in relation to our present
subject. His object was to describe a letter-lock which he had invented,
and which had up to that time given high satisfaction. We cannot do
better than transcribe the paper, as reported in one of the Liverpool
Journals, with a few abridgments.

“As your society are desirous of seeing any improvements or attempts at
them, I send you a stock-lock for inspection. The idea for its
construction I took from a letter-padlock. I had a lock of this
description made by Mr. Pooley twenty-five years ago, which has been in
use ever since on Brown, Shipley, and Co.’s safe....

“Its advantages I conceive to be--First, it cannot be picked, for there
is no key-hole. Second, it cannot be blown up by gunpowder, for the same
reason. Third, you cannot drill through the door so as to reach the
lock, for you are intercepted by a steel plate on which your tools will
not act: thus you cannot introduce gunpowder that way to force the lock
off. Fourth, you cannot bounce off the wheels in the interior with a
muffled hammer, for vulcanised India-rubber springs resist this. Fifth,
you cannot drill the spindles out, as their heads are case-hardened.
Sixth, you cannot drive them in, for they are countersunk in the door
about half-way through....

“Now let us set the lock to the word W O O D (any other four letters
might be used). When you set the lock, make a private record of them, so
that you may not forget them. If parties do not know your letters,
nothing but violence, applied by some means or other, can enable them to
get into your safe; for the lock will not open to any thing but its
talisman. Take off all the large wheels and open the lock: you will see
that the large wheels have a number of false chambers; if you get the
spurs of the bolt into three real chambers and one false, you are as
fast as ever, for all four must be right.

“Having placed your key and pointer outside the door to point to W on
brass-plate No. 1, the small wheel inside obeys the same impulse; then
maintain your small wheel steadily on this point, and the large wheel
No. 1 will only fit on at the right place, the true opening compartment
being opposite the spur of the bolt. It being necessary at the time you
set your lock that it should be open, proceed with Nos. 2 and 3 in the
same way, your pointer standing steadily at O. No. 4 is the same, the
pointer being held steadily at D. You should then shoot your lock two or
three times, to be sure you have made no mistake. Every time you shoot
your bolts out, turn your wheels away from the true chamber, and see
when you again turn your pointers to W O O D that your lock opens
freely; it is the proof that you have made no mistake, and you may now
venture to lock your safe. When you unlock the door, and find it
necessary to leave it open for a time, you should shoot the bolts as if
locked, and turn the wheels, so that no one may find what your real
letters are; and again adjust them to their proper places, in order that
the bolt may go back and enable you to re-lock. Once having locked the
door and turned the wheels from your real letters, you need not trouble
yourself with carrying the key, but leave it in any place beside the
lock.

“I believe two wheels would make a perfectly safe lock; three would be
quite so. I adopted four to make security doubly sure, as it would be
impossible in any given time to work the changes. On two wheels by
chance the lock might open; you can, however, calculate the chances
against this; and also three or four, the false compartment on the outer
rim being taken into calculation.    *   *   *

“If this lock is of any value, it should be known; if it has weak
points, let them be pointed out, and they may admit of a remedy; for we
ought not to be led to believe a lock is safe which is not so.”

In relation to the “first advantage” which Mr. Brown not unreasonably
supposed to be possessed by his lock--viz. that “it cannot be picked,
because it has no keyhole”--we shall have something to say in a future
page, where certain fallacies on this subject will be noticed. In the
meantime we may remark, that it is not a little creditable that a
leading Liverpool merchant should have invented a lock worthy of
occupying a position on his own safe for a quarter of a century; for we
may be quite certain that he would not have allowed the lock to maintain
that post of honour unless it had really (so far as experience had then
gone) served worthily as a safeguard to his treasures. And if it were
possible to collect all the by-gone specimens of lock-oddities, we
should probably find among them many highly-ingenious letter-locks; for
supposing a man to have a mechanical turn of mind, a lock is by no means
an unworthy medium for displaying it; the pieces of metal are so small
as to be easily manageable at a small work-bench in a small room. The
fondness for this sort of employment evinced by the unfortunate Louis
XVI. of France led to the common remark, “He is a capital locksmith, but
a very bad king.”

In an amusing article in the _Observer_, during the progress of the
“lock controversy,” was the following paragraph relating to
combination-locks of the letter or puzzle kind: “The French, in their
exposition of 1844, availing themselves of the permutation principle,
produced some marvels in the art; but the principle has not been adopted
in this country. The _Charivari_ had an amusing quiz upon these locks
when they first came out. It said the proprietor of such a lock must
have an excellent memory: forget the letters, and you are clearly shut
out from your own house. For instance, a gentleman gets to his door with
his family, after a country excursion, at eleven o’clock at night, in
the midst of a perfect deluge of rain. He hunts out his alphabetical
key, and thrusts it into his alphabetical lock, and says A Z B X. The
lock remains as firm as ever. ‘Plague take it!’ says the worthy citizen,
as the blinding rain drives in his eyes. He then recollects that that
was his combination for the previous day. He scratches his head to
facilitate the movement of his intellectual faculties, and makes a
random guess B C L O; but he has no better success. In addition to his
being well wet, his chances of hitting on the right combinations and
permutations are but small, seeing that the number is somewhere about
three millions five hundred and fifty-three thousand five hundred and
seventy-eight. Accordingly, when he comes to the three-hundredth he
loses all patience, and begins to kick and batter the door; but a patrol
of the National Guard passes by, and the disturber of the streets is
marched off to the watch-house.”




CHAPTER IV.

WARDED LOCKS, WITH THEIR VARIED APPENDAGES.


The more ordinary locks are of an oblong quadrangular shape. In nearly
all of them, either a bolt shoots out from the lock, to catch into some
kind of staple or box, or a staple enters a hole in the edge of the
lock, and is there acted upon by the bolt. A common room-door lock will
illustrate the first of these kinds, a tea-caddy lock the second. The
key, as is well known, enters a receptacle made for it; and the shaft of
the key generally serves as a pivot or axis around which the web or flat
part of the key may move in a circular course. During this movement the
web acts directly or indirectly on the bolt, driving it in or out
according to the direction in which the key is turned; the key impels
the bolt one way, certain springs act upon it in another, and the
balance between these two forces determines the locking and unlocking of
the bolt. _Wards_, or _wheels_, are contrivances for rendering the
opening difficult without the proper key; and it is of warded locks that
we shall chiefly treat in this chapter.

[Illustration: fig. 6. Interior of a back-spring warded lock.]

The annexed cut, fig. 6, represents the interior of an ordinary
back-spring lock, without tumblers. Such a lock may usually be known
from a tumbler-lock by this simple circumstance, that it emits a smart
snapping noise during the process of locking, occasioned by the pressure
of the spring when the bolt is in a particular position. In the woodcut
the bolt is represented half out, or half shot. At _a a_ are two notches
on the under side of the bolt connected by a curved part; _b_ is the
back spring, which becomes compressed by the passage of the curve
through a limited aperture in the rim _c c_ of the lock. When the bolt
is wholly withdrawn, one of the notches _a_ rests upon the rim _c c_;
and the force with which the notch falls into this position, urged by
the spring _b_, gives rise to the snapping or clicking noise. When the
bolt is wholly shot, the other notch rests in like manner upon the edge
of the aperture in the rim.

It must be obvious at a glance, that this back-spring lock is
objectionable on the score of security, on account of the facility with
which the bolt may be forced back by any pressure applied to its end, a
pressure which may often easily be brought to bear. At the centre of the
lock is seen the end of the key acting on a notch in the bolt, and
surrounded by wards.

[Illustration: fig. 7. Section to shew the action of wards.]

It is not at a first glance that the relation between the clefts in a
key and the wards of a lock can be duly appreciated; because the wards
present themselves to view as portions of circles to which nothing in
the key seems to correspond; but if it be borne in mind that the key has
a rotary motion within the key-hole around the pipe or barrel as an
axis, the circular form of the wards will be accounted for, and their
_section_ will be regarded as exhibiting the looked-for relation to the
wards of the key. In the annexed cut, for example (fig. 7), which
represents a portion of the interior of a warded lock, the curved pieces
of metal are the wards (two in this case); and there are two clefts in
the bitt of the key to enable the latter to take its circular course
without interruption from the wards. If the clefts were other than they
are, either in number, position, or size, this freedom of the key’s
movement could not be obtained.

[Illustration: fig. 8. End sections of keys.]

When once the opinion became established that a lock is rendered secure
by virtue of its wards, (a theory which we shall have to discuss in a
later page,) much ingenuity was displayed in varying the wards of the
lock, the clefts of the key, and the shape of the keyhole. Even if the
two former were unchanged, a change in the latter might add to the
puzzlement of the arrangement. For instance, in the annexed cut (fig.
8), all the six keys represented may have clefts or cuts exactly alike,
all alike adapted to the wards of one particular lock; yet the
differences in the _thickness_ of the web are such, that if the keyholes
were shaped in conformity therewith, each keyhole would be entered by
one of these keys; _b_ and _c_ differing from _a_ in the relative
thickness at different points, and _d_, _e_, and _f_ having certain
curvatures and cavities not to be found in the other three.

[Illustration: fig. 9. Examples to shew the action of “master,” or
“skeleton keys.”]

But without waiting for the detailed examination of the relative
security and insecurity of locks, we may at once shew how simple is the
principle which renders the warded system fallacious. In fig. 9 we
shall be able to illustrate this. Numbers 1, 2, and 3, all appear very
different keys, and it is quite true that neither one would open a lock
adapted for either of the other two; and yet the very simple arrangement
No. 4 would open all three. This No. 4 is called a _skeleton-key_; and
the relation which it bears to the others may be expressed in the form
of a proposition thus: at any point where there is solid metal in _all_
the keys, there must (or may) be solid metal in the corresponding part
of the skeleton-key; but at any point where there is a vacancy or cavity
in _any_ of the keys, there must be a cavity in the corresponding part
of the skeleton-key. If Nos. 1, 2, 3, 4, be examined, this proposition
will be found to be borne out; there is so much cavity in No. 4 that it
avoids the wards in all the three locks, nothing being required but the
tongue of metal to move the bolt. Sometimes, to add to the safety, wards
are attached to the front as well as the back plate of the lock; and
then there may be a double series of notches required in the key, such
as in No. 5; but if this be compared with Nos. 9, 10, 11, it will be
found that although no one of the four would open a lock adapted for
either of the other three, yet the skeleton-key No. 12 would master them
all, having cavities wherever any of the others have cavities. This is
the theory of the _master-key_, by which one key may be made to command
many locks. Nos. 6 and 7 have complicated wards; but the key is so much
cut up as to be weakened more than is desirable. No. 8 enables us to
point out the difference between two distinct classes of keys. Keys with
pipes or barrels fitting on a pin or pipe-shaft can only open a lock on
one side of the door or box; but a key with a solid stem, as No. 8, has
the clefts so cut as to open the lock from either side, as in a
street-door lock: it is, in fact, two warded keys fixed end to end, only
half of which is employed at one time in opening the lock.

[Illustration: fig. 10. Wards of an old French lock.]

Some of the warded locks of the last century are curious. While the idea
prevailed that a complicated ward gave security, there was room for the
exercise of ingenuity in varying the shape of the wards. Fig. 10 is
copied from the great French work. It represents the cuts in the key,
and also (seen perspectively) the complicated forms of the pieces of
metal which constitute the wards corresponding with those cuts. The
aperture in the key at 16 fits upon the metal surrounding the keyhole at
18; and the M-shaped cuts at 17 fit in like manner upon the
similarly-shaped metal pieces at 19.

Another example of a similar kind is shewn in fig. 11, where an anchor
appears to have been the favourite form. The anchor cuts in the key are
shewn at 26; while in the wards the bottom of the anchor is near the
keyhole at 28, and the top at 29.

[Illustration: fig. 11. Wards of an old French lock.]

[Illustration: fig. 12. Wards of an old French lock.]

A similar illustration occurs in fig. 12, where the star-like cuts at 34
on the key correspond with the star-like wards at 33.

[Illustration: fig. 13. Exterior of an old secret lock.]

[Illustration: fig. 14. The same, with a portion of the front let down,
shewing the key-hole.]

From the fifteenth to the eighteenth centuries locks were made in
France, on which a vast amount of care and expense was bestowed. They
were, in an especial degree, decorative appendages as well as
fastenings. They were of three kinds: room-locks, buffet-locks, and
chest-locks; they were fixed on the outside of the door or lid, so as to
be fully visible. The key had a multitude of perforations which bore no
particular relation to the wards of the lock, but which were regarded as
tests of the workman’s skill. The honorary distinctions awarded to
apprentices and aspirants in the art depended very much on the number
and fine execution of these perforated keys. The locks, considered as
fastenings, had slender merit; although usually throwing four bolts,
they were not very secure. Fig. 13 represents the exterior of a lock
made about the year 1730, by Bridou, a celebrated Parisian locksmith. It
was a lock belonging to a coffer or strong chest; all the works being
sunk below the level of a carved architectural moulding or ornament.
There is a secret opening near the part C, forming a portion of the
ornamental design; it allows a bolt, shewn at D, fig. 14, acted on by
the spring E, to be touched, by which a doorway opens upon the hinges at
B B. A A are a sort of pilasters, which aid in forming a hold for the
bolts. The little ornament at C is drawn down by the hand, opening the
secret door and revealing the key-hole G. S S, O O, Z Z, are ornaments
fastened on at _b c d_, fig. 14, by nuts and screws, intended to display
the skill of the workman. The lock itself, access to the keyhole of
which is obtained within the secret door, has nothing very remarkable
about it.

[Illustration: fig. 15. Examples of true and false keys.]

Mr. Chubb, in his paper read before the Institute of Civil Engineers,
illustrated the insecurity of the warded lock by the example of one
which had actually been placed in the strong-room of a banking house,
and which is represented in the annexed cut (fig. 15). The wards are
here shewn, surrounding the central key-pin; and from the appearance of
the key, shewn at _a_, it is evident that these wards must have been
rather complex. But the uselessness of the wards was proved by the
result. A burglar employed an instrument, shaped like that at _b_,
having on one of its faces, or sides, a layer of wax and yellow soap;
this instrument, being introduced through the keyhole and turned a
little way round, brought the soft composition in contact with the ends
of the wards, and these ends thus left their impress on the composition.
A false key was then made, as at _c_, which, however clumsy it may
appear, has a cavity, or vacuity, where there is a cavity in the true
key; and by such a surreptitious instrument was the lock opened. Even so
rude an instrument as _d_, by passing round the wards, might open such a
lock.

We are somewhat anticipating the full consideration of this subject;
but it is desirable at once to explain how and why an improvement on the
warded lock was sought for.

In connexion with the fanciful eighteenth-century locks, lately adverted
to, we may remark, that no less a man than Louis XVI. was an amateur
workman in this department of mechanical art--or at least in smith’s
work, which in France is generally considered to include lock-making.
Sir Archibald Alison says, in his _History of Europe_:--“He had an
extraordinary fondness for athletic occupation and mechanical labour;
insomuch that he frequently worked several hours a-day with a blacksmith
of the name of Gamin, who taught him the art of wielding the hammer and
managing the forge. He took the greatest interest in this occupation,
and loaded his preceptor in the art with kindness; who returned it by
betraying to the Convention a secret iron recess which they had together
worked out in the walls of the cabinet in the Tuileries, wherein to
deposit his secret papers during the storms of the Revolution.” There
are not wanting indications that the unfortunate monarch wrought upon
locks, as well as upon safes and strong-rooms.

Besides wards, there have been numerous other contrivances for adding to
the security of locks--including screws, escutcheons, spiral springs,
wheel-and-pinion work, alarums, and multiple bolts. As these are not of
sufficient importance to be treated in separate chapters, we shall here
give just so much notice of them as will illustrate their general
character. Some of them are found combined with the “tumbler” principle,
presently to be described; but all of them, it is now well known, were
employed in various, ways when the tumbler lock was but little
understood, and when the warded lock was held in esteem.

The Marquis of Worcester, whose curious _Century of Inventions_, written
nearly two hundred years ago, contains so many suggestions which
ingenuity has since developed into practical completeness, gives four of
his inventions in the following words:--

69. “A way how a little triangle screwed key, not weighing a shilling,
shall be capable and strong enough to bolt and unbolt, round about a
great chest, an hundred bolts, through fifty staples, two in each, with
a direct contrary motion; and as many more from both sides and ends;
and, at the self-same time, shall fasten it to the place beyond a man’s
natural strength to take it away; and in one and the same turn both
locketh and openeth it.

70. “A key with a rose-turning pipe and two roses pierced through
endwise the bit thereof, with several handsomely contrived wards, which
may likewise do the same effects.

71. “A key, perfectly square, with a screw turning within it, and more
conceited than any of the rest, and no heavier than the triangle screwed
key, and doth the same effects.

72. “An escutcheon, to be placed before any of these locks, with these
properties: First, the owner, though a woman, may with her delicate hand
vary the ways of causing to open the lock ten millions of times beyond
the knowledge of the smith that made it, or of me that invented it.
Second, if a stranger open it, it setteth an alarum a-going, which the
stranger cannot stop from running out; and besides, though none shall be
within hearing, yet it catcheth his hand as a trap doth a fox; and
though far from maiming him, yet it leaveth such a mark behind it as
will discover him if suspected; the escutcheon or lock plainly shewing
what money he hath taken out of the box to a farthing, and how many
times opened since the owner had been at it.”

Mr. Partington, in his edition of the marquis’s singular work, makes a
few comments on these lock-and-key contrivances. He says that the lock
is evidently intended to operate on the principle of applying a _screw_
for the purpose of moving the bolt, instead of using a key as a lever
for this purpose. That such a plan might be applied to locks generally,
he observes, there can be no doubt; and by a similar contrivance the
large keys at present in use for outer doors, iron chests, &c. might be
advantageously reduced by this means. By employing the escutcheon
mentioned by the marquis, much additional security would be obtained. It
must be confessed, however, that many of the marquis’s statements are
difficult to credit.

The escutcheon has been a favourite resource with lock-makers. Mr.
Mordan’s escutcheon, for instance, introduced before the Society of Arts
in 1830, is a contrivance to be placed temporarily over the keyhole of a
door, to prevent the picking of the lock during the owner’s absence. The
escutcheon, or “protector,” has a short pipe which, after the door has
been locked, is thrust into the keyhole; attached to the pipe is a small
lock, on Bramah’s or any other convenient principle, so contrived that,
on turning its key, two lancet-shaped pieces fly out laterally and bury
themselves in the wood. The escutcheon cannot be removed until the small
key has reacted upon the small lock; and until this removal has taken
place, the large key cannot reach the keyhole.

A curious application of the escutcheon principle attracted some
attention among locksmiths about seventy years ago. One of the first
premiums awarded by the Society of Arts, after the commencement of their
“Transactions,” was to Mr. Marshall, for a “secret escutcheon,” in 1784.
In his description of his new invention, he adverts to the marquis of
Worcester’s wonderful escutcheon, and to the many attempts which have
since been made to produce an apparatus which should realise the
marquis’s description. He supposes that the letter padlock originated as
one among many varieties of these imitative inventions; but this may be
doubted. Mr. Marshall’s contrivance, however, was in effect an endeavour
to improve upon the letter-lock. He considered it an objection that, in
ordinary locks of this kind, the letter-rings admit of no variation of
place; and he sought to remedy this defect. It is not so much a new
lock, as an escutcheon for a lock, which he produced. There is a studded
bar passing through a barrel; there are five rings which work
concentrically on this barrel; there are letters on the outer surfaces
of the rings, and notches on the inner surface; but when, by the usual
puzzle-action of the rings, the notches in them have been brought into a
right line with the studs of the bar, the result is, not that the hasp
of a padlock is raised, but that the escutcheon is removed from the
keyhole of an ordinary lock. Mr. Marshall’s contrivance, therefore, is
not so much a ring padlock, as a puzzle-ring security for the escutcheon
of a fixed lock.

Some locks work by a screw and a spiral spring, instead of an ordinary
key. Mr. W. Russell received a silver medal from the Society of Arts,
about thirty years ago, for a new mode of locking the cocks of
liquor-casks. Under ordinary circumstances, as is well known, the cock
of a barrel or cask is in no way secure from the action of any one who
can approach near enough to touch it; and different methods have been
adopted of obtaining this security or secrecy. One plan is to employ a
perforated cap, soft-soldered to the barrel of the cock, immediately
over the grooved plug, the top of which plug is formed to the shape of
the perforation, and a socket-key of the same form is introduced to turn
the plug or open the lock. Another plan is to employ an iron saddle or
staple, passing over the plug and below the bottom of the cock, through
which a bolt is put, and a pendent padlock attached. The first method is
very inefficient; the second is much superior, and has been largely
adopted for locking the cocks of coppers, stills, vats, and other large
vessels. But Mr. Russell thought some further improvement wanted. He
caused a hole to be bored through the barrel, and to some depth into the
plug when the latter is in the position for closing the cock. A stud
works into this hole in such a way, that when the stud is driven home,
the plug cannot be turned or the lock opened. The stud is attached at
its other end to a spiral spring connected with a screw; a key is
employed, the hollow pipe of which has an internal screw; and when this
key is inserted in the cock-barrel and turned twice round, it draws back
the stud, and allows the plug to be turned round in the proper way for
opening the cock.

It is not often that wheel-and-pinion work is introduced into locks; the
delicacy, the costliness, the weakness, and the tendency to get out of
order, would all militate against the frequent adoption of such a
course. It is, however, adopted occasionally. Mr. Friend’s secret-lock,
introduced to the notice of the Society of Arts in 1825, had a train of
wheels which acted upon the bolt, driving it out whenever the circular
arcs of three wheels moved against it, but allowing a spring to force it
back again whenever a deep cleft in each of the wheels locked into a
stud on the bolt. There were certain numbers on a guide-plate, and a
power of combining these numbers in great variety; and a provision that
the bolt could be unlocked only by the same combination of numbers which
had locked it. The guide-plate was a separate piece of apparatus,
carried in the pocket of the user as a companion to the key. The key was
of no use without the guide-plate, nor the guide-plate without the key.
The user ‘set’ the numbers on the guide-plate, then applied it to the
face of the lock, then introduced the key into the key-hole, and turned
the key partially round; the bolt was now shot, and the guide-plate
removed. If the key were used without the guide-plate, the bolt might be
locked, but it was always unlocked again by the time the key had made a
complete circuit. There was considerable ingenuity in the idea of this
lock; but we believe it never went further than a model. Indeed many of
the locks elaborately described in books have never had an existence as
acting working locks.

A very ingenious principle has been occasionally introduced, in which
clock-work regulates the interval of time which must elapse before a
lock can be opened, even with its proper key. The object is, to ensure
the safety of the lock during a journey, or until a particular person be
present, or until the locked article is conveyed to a particular room. A
patent was taken out in 1831 for a lock on this principle by Mr.
Rutherford, a bank agent at Jedburgh. Against the end of the bolt of the
lock is placed a circular stop-plate, so adjusted that the bolt cannot
be withdrawn until a particular notch in the rim of the circular plate
is opposite the end of the bolt. The plate is put in rotation by
clock-work. As the notch can be set at pleasure to any required distance
from the end of the bolt, the lock may be secured against being opened,
either by its own or any other key, until any assigned number of minutes
or hours after it has been locked; for the plate may be made to revolve
either slowly or quickly, by varying the number of wheels in the
clockwork. When the lock is used for boxes or portable packages, the
clockwork must be moved and regulated by a spring; but when it is
applied to closets or safes, a descending weight and a pendulum may be
employed. It is manifest that this system is susceptible of being
greatly varied in its mode of application; and it has many points of
interest about it. That a man cannot open his own lock with his own
proper key, until the lock gives permission by assuming a particular
state or condition, certainly strikes one as being susceptible of many
useful applications, where _time_ is an element taken into the account.

A curious alarum-lock was invented by Mr. Meighan, in 1836, in which the
bell or alarum is not placed behind a door, as in many alarum
contrivances, but within the lock itself. Two or more studs are placed
on the bolt, which press against the lower end of a small tumbler; the
movement of the tumbler elevates a hammer; but as soon as the point of
the tumbler becomes released from the stud, a spring presses the hammer
down forcibly, and causes it to strike against a small bell placed near
it. This sounding of the bell will be repeated, during the shutting of
the bolt, as many times as there are studs to act upon the point of the
tumbler.

Much of the ingenuity which has been displayed in locks depends on the
employment of multiple bolts, there being all the additional strength
which results from the use of two or more bolts instead of simply one.
Ordinary doors seldom afford us examples of these double bolts; but they
may be frequently seen in cabinets and desks, where two staples fixed
to the lid fall into two holes in the lock, and are retained by two
bolts. The most remarkable and complicated varieties, however, are those
in which the bolts, instead of shooting parallel and nearly together,
shoot in wholly different ways; one up, one down, one to the right, one
to the left, and so on. It is on safes, strong boxes, and the doors of
strong rooms containing valuable treasures, that such locks are usually
placed. The mechanism is such that the key acts upon all the bolts at
once, through the intervention of levers and springs of various kinds.

[Illustration: fig. 16. Multiple bolts of an old chest-lock.]

The above woodcut represents a very curious specimen of these
multiple-bolt locks. It is copied from the great French work; and the
ponderous chest to which it is attached is, we are told by Réaumur,
“known at Paris by the name of the strong German coffer.” He further
says, “nothing is wanting in these coffers on the score of solidity.
They are made entirely of iron; or if of wood, they are banded both
within and without with iron; and can only be broken open by very great
violence. Their locks are almost as large as the top of the coffer, and
close with a great number of bolts. The one which we have engraved has
twelve fastenings; they have been made with twenty-four, or more.” His
next remark on the subject is a sensible one: “Notwithstanding the large
size of these locks, and all the apparatus with which they are provided,
they correspond but ill with the solidity of the rest of the coffer. If
we have given a representation of one, it is chiefly to shew how little
confidence one could have in such a lock, and what are its defects, in
order that we may avoid them.” It is not difficult, by tracing the
action of the several levers, to see how one movement of the key, in the
centre of the lid, would act upon all the bolts. In the engraving (fig.
16) _a_, _f_, _h_, _c_, are the four corner bolts; six others, _a d e_,
_a d e_, are on the long sides, three on each; and two, _b g_, on the
short sides. Every bolt is provided with a spring, of which three or
four are shewn at Z Z Z. There is no staple or box to receive each bolt;
but all shoot or snap beneath the raised edge E running round the top of
the box just within the exterior at A A. The keyhole in the front of the
box at D is a deception or mask; the real keyhole is in the middle of
the lid concealed by a secret door opened by a spring. When the key has
moved the great central bolt, this acts upon the other bolts P Q R S T,
&c.; V V are studs which act upon two of the bolts; Y Y are staples
confining the great bolt; _k_, _l_, _c_, _p_, _x_, are small levers
which transmit the action to the corner bolts; _q_, _r_, _s_, _t_, _n_,
are the small levers which render a similar service to the side and end
bolts; L L within the chest, and M M on the lid, are contrivances for
limiting the movement of the latter; C H, H C are iron straps or bands
by which the interior of the chest is strengthened. After all, this is
not so much a lock as a series of spring latches.

If a lock can be picked, the picking is as effective whether the lock
has one bolt or twelve bolts. This fact led Mr. Duce, in 1824, to
construct, instead of a four-bolt lock, four distinct one-bolt locks,
fixed in the same frame and opened by the same key; the bolts to be
moved in succession instead of simultaneously. It would require four
times as long to pick this as a four-bolt lock of similar action.

There have been many other varieties of the multiple bolt, but we need
not stop to describe them.




CHAPTER V.

ON TUMBLER, OR LEVER LOCKS.


Security being the primary object in all locks, any considerations as to
mechanical ingenuity and graceful decoration give place to those which
relate to safety. A spring lock may be ingenious and even beautiful in
its construction, but an imitative key will easily open it. Hence arose
the invention of wheels or wards; and as wards failed in
trustworthiness, they in their turn yielded to something better. We have
already explained how the insecurity of mere warded locks arises; and we
shall have something more to say on the subject in a future chapter. It
is sufficient here to remark, that wards, springs, screws, alarums,
wheel-work, escutcheons,--all, however useful for particular purposes,
are wanting in the degree of surety which we require in a lock. Hence
the invention of _tumblers_, _levers_, or _latches_, which fall into the
bolt and prevent it from being shot until they have been raised or
released by the action of the key. We have been unable to ascertain at
what time, or in what country, or by whom, tumbler-locks were invented.
The invention has been claimed by or for persons subsequently to the
year 1767, when the celebrated French treatise (_Art du Serrurier_)
already referred to was published; and yet this treatise contains
numerous examples of simple tumbler locks of ingenious construction, as
will presently be shewn.

[Illustration: fig. 17. Simple tumbler lock.]

One of the most elementary forms of tumbler-lock is shewn in fig. 17. In
this case the bolt, instead of having two notches in the bottom edge,
like those in the back-spring lock, fig. 6, has two square notches or
slots in the upper edge; and as the key acts upon the bolt, these
notches must of course share in whatever movements the bolt is subjected
to. Behind the bolt is a kind of latch or tumbler (the lower part of
which is shewn by dotted lines), with a stump or projecting piece of
metal at _a_; the tumbler moves freely on a pivot at the other end, and
is made to rise through a small arc whenever the key acts upon the bolt.
When the bolt is wholly shot, the stump falls into one notch and
prevents the motion of the bolt; when wholly unshot or withdrawn, the
stump falls into the other notch, and equally prevents the motion of the
bolt. It is not, therefore, until the key, by elevating the tumbler, has
raised the stump out of the notch, that the bolt has freedom of
movement. If the shape of the key does not enable its web to effect this
elevation to a sufficient degree, the bolt remains immovable; and to
this extent a certain additional security is obtained by making the
shape of the key significant as well as the wards.

[Illustration: fig. 18.]

[Illustration: fig. 19. Old French lock.]

The tumbler-principle, as we have said, is difficult to trace to its
origin on account of the various aspects which it presents; but the
great French treatise proves that the locksmiths of France were familiar
with tumbler-locks a century ago. The plates of that work represent the
details of numerous locks, on the upper edge of the bolts of which were
notches called _encoches_, as at _o k_ fig. 18; into these notches sank
a small iron stud or stump called the _arrêt du pêne_, or bolt-stop,
shewn in fig. 19, attached to the upper portion of the _gâchette_ or
tumbler, which, for the sake of economy of metal, is made in the form of
a triangular spring in front of the bolt _k i_; and not until the key,
by its circular action, had raised this stud out of one or other of the
notches, could the bolt move to the right or left. The stud was
generally fixed to a spring which forced it down again into the notch as
soon as the action of the key had ceased. Sometimes, however, the stud
was fixed to the bolt, and the notches were in a separate tumbler or
_gâchette_ (see E E, fig. 21); and in other instances, again, the stump
was fixed to the case of the lock and caught into notches in the bolt.
It will be seen, when we come to treat of tumbler-locks of later date,
that there was much in these early locks to point out the way. Fig. 19,
copied from the French work, represents a lock of the box or casket
kind. Two staples, fixed into the cover, fall into two cavities or
receptacles at C _d_; and a short bolt in each receptacle catches into
each staple, one near _g_ and one near _h_. The small bolt _q_ is
attached to the upper extremity of the lever _q r s_, fig. 19, and shewn
separately in fig. 20; and by the pressure of a spring _a_ (fig. 19)
upon this lever, the bolt _q_ is kept locked in the staple. The
vertical portion of this spring presses at its lower end on another
spring _p_ (fig. 19) of singular curvature; and attached to the
horizontal part of this second spring is the stud, which falls into a
notch in the top of the bolt. The action of these parts, then, is as
follows: when the key is placed upon the key-pin at Z, and turned round
in the direction in which the hands of a watch move, the bitt presses
against the tail _s_ of the lever, moves it upon its centre Z, fig. 19,
_v_, fig. 20, to the left, and consequently moves the upper part _q_ to
the right, drawing it out of the receptacle and liberating the staple
within C. Thus it will be seen that the lever _q r s_, held in one
position by the spring _a_, forms in itself a simple kind of spring
catch-lock, and was, in fact, formerly used as such, without any other
appendages except the staple in the lever, into which the catch _q_
fitted on shutting down the lid. So also we may regard the other
portion, fig. 18, or _k i p h_ (fig. 19), as forming a separate lock;
for the key after having passed S comes in contact with the triangular
spring, which it raises thereby, lifting the stud out of the bolt, and
exerting pressure against the barbs of the bolt _n_. Fig. 18 shoots the
bolt _k_, and also the short bolt _l_, which passes through the staple
in the cavity _d_, fig. 19.

[Illustration: fig. 20.]

The lock represented in the four following figures is also from M. de
Réaumur’s chapter on locks in the work referred to. In this lock the
tumbler-principle is carried out in a very elaborate manner, for not
only is the stump or stud H (fig. 23) attached to a very strong spring
(best shewn at H, fig. 22), which holds it with considerable force in
one of the three notches of the principal bolt R S (fig. 24); but there
is also a second set of notches E E in the _gâchette_ G O (fig. 21), and
a pin attached to one of the plates of the lock fits into one of these
notches, thereby preventing the bolt from being moved until the
_gâchette_ is lowered by the revolution of the key; so that in
attempting to pick this lock, not only must the spring H be raised so as
to release the stud from the notches of the great bolt, but the
_gâchette_ must be lowered to disengage the fixed pin from the notches.
There is yet a third source of security. Attached to the large bolt are
short projecting pins F (fig. 21), against which an arm or detent, G F,
of the _gâchette_ projects, thus preventing the bolt from being shot
back by any pressure applied to its extremity S.

[Illustration: fig. 21. Details of an old French lock.]

[Illustration: fig. 22. Another view of the same.]

[Illustration: fig. 23. Another view of the same.]

[Illustration: fig. 24. The two bolts detached.]

There are a few details relating to this remarkable lock, which may as
well be introduced here in order to complete the description. The
principal bolt can be shot twice, or be _double-locked_; hence it is
furnished with three barbs for the key to act against, and with three
notches for the spring-stud. The lower bolt I K can be shot by the
horizontal pressure of the button P (figs. 22, 23), which is situated on
the inner side of the door to which this lock is attached, so that a
person inside the room can secure the door against any one on the
outside who is not furnished with the proper key, for it must be
remarked that the small bolt as well as the large one is acted on by the
key. Now supposing the small bolt to be shot or locked, it is kept so by
the pressure of the coiled spring Q (figs. 21, 22). But this small bolt
is connected with the large one by means of the bent lever O N M (figs.
21, 24), which turns on a pin N attached to the main bolt. Now, when
both bolts are either fully shot or unshot, the arm O N lies flat
against and parallel with the main bolt; but when the large bolt is
unshot and the small one not moved, the arms O N, N M, fall into an
inclined position, and the arm O N passing a little below the main bolt
comes within the range of the web of the key, which in its revolution
causes the bent lever to move upon its centre N, thereby restoring O N
to its horizontal position, and at the same time causing the arm N M to
move from right to left, or in the direction for unshooting the small
bolt; the end of this arm thus catches into a mortise V (figs. 21, 24)
in the small bolt, and immediately unlocks it.

But to return to the subject of tumbler-locks. About the year 1778, Mr.
Barron introduced that species of double-action (as it may perhaps be
termed) which so greatly increases the security of the simple tumbler,
fig. 17. In the tumbler-locks previously made, if the tumbler were
raised sufficiently high, the lock could be opened: there was no such
possibility as raising it _too_ high; but Mr. Barron, by his invention,
patented 31st October, 1778, rendered it absolutely necessary that a
limit should be put to the height to which the tumbler should be raised,
by rendering the bolt equally immovable whether the tumbler were too
much or too little raised. Another important improvement was the
introduction of two tumblers instead of one. The bolt has in its middle
a slot or gating notched on both edges, the notches being fitted for the
reception of studs fixed to the tumblers. Supposing the studs or stumps
of the tumblers to be resting in the lower notches, they require to be
elevated to the general level of the gating before the bolt can be
moved; whereas, on the other hand, if the tumblers were raised ever so
little too high, the studs will enter the upper notches, and prevent the
shooting of the bolt. The lower edge, or belly, of each tumbler is acted
on by the steps of the key during its circular movement; the leverage of
the key being so exactly adjusted as to raise the tumbler to the desired
height and no further. The tumblers are made unequally wide, so that
steps or inequalities in the bit of the key are requisite to lift them
both to the proper height. There are thus two improvements introduced:
there are two tumblers instead of one, and each tumbler has a double
instead of a single action.

This ingenious and very useful lock is represented, so far as regards
its governing principle, in fig. 25. The bolt is here seen to have a
peculiar slot or hole cut in it, consisting of a narrow horizontal
passage or gating, with three notches above it and three below it. These
double notches might be available even for one tumbler only; but Barron
used two or more for the sake of additional security. In fig. 25 there
are two tumblers shewn, expressed by dotted lines; both are hinged to
one pivot, both are raised by the same action of the key, but the stump
on the one tumbler does not coincide in position with that on the other.
It will be seen that if the studs of the tumblers rested in the lower
notches, they would require to be elevated to the level of the gating
before the bolt could be moved; while, on the other hand, if lifted too
high, the stumps would be caught in the upper notches, and would equally
prevent the passage of the bolt, The tumblers are unequally wide; and
the bitt of the key is stepped or notched in a corresponding way, that
there may be one step fitted to act upon each tumbler. Mr. Barron also
adopted the reverse arrangement of having the stump on the bolt, and the
openings in the tumblers; so that the principle of his patent may be
concisely expressed as being “an arrangement to allow a stump on the
tumbler to pass through an opening in the bolt, or a stump on the bolt
to pass through an opening in the tumbler.”

[Illustration: fig. 25. Action of Barron’s tumbler-lock.]

A very elaborate tumbler-lock, patented 23d February, 1790, by Mr.
Rowntree, contrasts remarkably with the simplicity of Barron’s lock. Mr.
Rowntree’s lock consisted of tumblers combined with revolving discs or
wheels. Its mechanism may be understood from the following description
and engravings. The same letters refer to the same parts in the several
figures.

[Illustration: fig. 26.

fig. 27.

fig. 28.

fig. 29.

fig. 30.

Details of Rowntree’s tumbler-lock.]

A A is the plate which encloses the whole mechanism of the lock, and
fastens it to the door; B B is the bolt, guided in its motion by sliding
under the bridges C D; E E are pillars which support a plate covering
the works; F are the circular wards surrounding the centre or key-pin;
and _a_ shews the position of the key, which, in turning round, acts in
a notch _r_ in the bolt, and propels it; G, the tumbler, is a plate
situated beneath the bolt, and moving on a centre-pin at _d_; it has a
catch or stump _e_ projecting upwards, which enters the notches _s_ or
_g_ in the bolt, and thereby retains the latter for backward or forward
motion, as the case may be; H is a spring which presses the tumbler
forward. The key _a_, in turning round, acts first against the part _c
c_ of the tumbler, and raises it so as to remove the stump from the
notches; it can then enter the notch _r_ in the bolt, and move it. So
far there is no particular security; but Mr. Rowntree sought to obtain
it by the following means. There is a piece of metal _h_ fixed to the
lower side of the tumbler, called the _pin_; when the tumbler is caught
in either notch of the bolt, the pin applies itself to a cluster of
small wheels I, fitted on one centre-pin beneath the tumbler; the edges
of these wheels stop the pin, and prevent the tumbler from being raised.
But each wheel has a notch cut in its circumference I; and it is only
when the wheels are so placed that all their notches lie in a right
line, that the pin can enter this compound notch and allow the tumbler
to rise. The wheels must therefore be all adjusted to position; and this
is effected by a number of levers K centred on one pin at _k_; at the
opposite end each lever has a tooth _m_ entering a notch in the wheel
belonging to it; so that when any lever is pressed outward, it turns its
wheel round. Now this pressure of the levers is brought about by a
spring _n_ applied to each; and when so pressed, the levers rest against
a pin _o_ fixed in the plate. The key is so cut as to determine the
extent to which the levers shall act upon the wheels. The key first
operates from the curved part _p p_ of the levers K, and raising them,
turns all the wheels I at once into the proper positions; in turning
further round, it then operates on the part _c c_ of the tumbler,
causing the latter to rise and to release the bolt; and in turning still
further round, it (the key) seizes the notch _r_ of the bolt, and shoots
it. The key is cut into steps of different lengths, as shewn at V V;
each step operates on its respective lever K in a different degree from
the others; the notch at _s_ acts upon the tumbler, and the plain part
_t_ moves the bolt.

We now proceed to notice the modern tumbler-lock. This was arranged by
Bird, whose patent, bearing date 29th October, 1790, was for a series of
four double-acting tumblers, differing in no respect from those patented
by Barron, and closely resembling those in use at the present time in
the best tumbler-locks. We will describe the modern tumbler-lock more
particularly when we have gone through a few historical details on the
subject.

Messrs. Mitchell and Lawton obtained a patent bearing date 7th March,
1815, for a lock in which were combined with the bolt and double-acting
tumblers, a series of movable wards, and a revolving curtain for closing
the key-hole. The action of the wards was peculiar. On introducing any
key or instrument, and passing it round, a number of movable wards or
pieces were thrown out so as to prevent the key from being turned back
or withdrawn. It was necessary therefore to pass round the key so as to
unlock the lock, and if that were not possible, as in the case of a
false key being used, it was held permanently, and could only be
released by destroying the lock, When the bolt was once shot, the wards
were carried up so as to leave a clear passage for the key. This lock
does not appear ever to have come into use, on account of the violence
required in case a wrong key should be used either by accident or
design.

The detention of a wrong key in this lock appears to have suggested the
contrivance of a _detector_. This was first made by Ruxton, whose patent
is dated 14th May, 1816. His detectors were of various kinds, the object
of each kind being to give information to the owner in case any one of
the tumblers should be overlifted in an attempt to pick the lock, which
fact would be discovered on the next application of the true key. This
is precisely the object of the detector in tumbler-locks at the present
day, and Ruxton accomplished it by somewhat similar means. He also had a
contrivance for holding a false key, as in Mitchell and Lawton’s lock;
and he recommended this form of detector in the following words: “It is
true that in this case the lock will have to be destroyed in order to
open the door: the result is frightful; but we think the more terrible
the result, the less likely would any one be to tamper with it.”

We now come to Chubb’s lock, patented 3d February, 1818, which consisted
of double-acting tumblers and a peculiar kind of detector. This lock has
been made the subject of various patents obtained in the years 1824,
1833, 1846, and 1847. This lock[4] consists of six separate and distinct
double-acting tumblers, all of which must be raised to a particular
height, neither more nor less, in order that the bolt may pass. It also
comprises a _detector_, by which, should any one of the tumblers be
lifted too high in an attempt to pick or open the lock by a false key,
it would be immediately detected on the next application of the proper
key. The tumblers are flat pieces of iron or steel, with the plane of
the surface vertical, and pivoted at one end; and the following is the
mode in which the key, the tumblers, and the bolt, are brought into
mutual action.

  [4] The lock about to be described is the latest and most complete
  form of Chubb lock up to the date of the Great Exhibition. The various
  additions and alterations which have been made in the lock since that
  date will be noticed in a subsequent chapter.

The bolt shoots in and out of the lock in the usual way. It has a square
stud or stump riveted on one surface; and it is to furnish obstructions
to the passage of this stud that the tumblers are provided. All the six
tumblers are pivoted to one pin at the end, giving to each of them a
small leverage, each independent of the others. There are six springs
which press these tumblers downwards, one to each tumbler. There is a
longitudinal slot or gating in each tumbler, large enough to receive the
stud of the bolt; and unless all the six slots (supposing there to be
six tumblers) coincide in height or position, the stud will not have a
clear passage for moving to and fro. Now the slots are purposely made
nearer the upper edge in some of the tumblers than in others, all the
six being different in this respect; so that if they are all lifted
_equally_, the slots do not coincide, and the bolt and its stud will not
pass. The tumblers must then be raised _unequally_, those to be most
raised which have the slot nearest to the lower edge. To effect this,
the bit of the key is cut into six steps or inequalities, each to act
upon one particular tumbler, and each cut or stepped to the exact depth
which will suffice for the proper raising of the tumbler. The key is
inserted in the keyhole, and is turned; the six steps raise the six
tumblers all to the proper height, to leave a clear passage along the
slots; and the extreme end of the key then acts upon the bolt itself,
and shoots it. To unlock it again, the same or a duplicate key must be
used; for if another key be employed, differing by ever so little from
the proper one, some one or more of the tumblers will be lifted either
a little too much or not quite enough; and in either case the stud of
the bolt will catch above or below the slot, instead of having a clear
line of movement along the slot itself. After both locking and
unlocking, the springs force the tumblers down as far as they can go,
burying the stud in the recesses above the slot; so that the tumblers
must be raised by the key both for locking and unlocking.

The doctrine of chances has wide play in determining the relative
position of the six tumblers. In Mr. Chubb’s essay this part of the
subject is treated in the following way: “The number of changes which
may be effected on the keys of a three-inch drawer-lock is 1 × 2 × 3 × 4
× 5 × 6 = 720, the number of different combinations which may be made on
the six steps of unequal lengths (on a six-tumbler lock), without
altering the length of either step. The height of the shortest step is,
however, capable of being reduced 20 times; and each time of being
reduced, the 720 combinations may be repeated; therefore 720 × 20 =
14,400 changes. The same process, after reducing the shortest step as
much as possible, may be gone through with each of the other five steps;
therefore 14,400 × 6 = 86,400, which is the number of changes that can
be produced on the six steps. If, however, the seventh step, which
throws the bolt, be taken into account, the reduction of it only ten
times would give 86,400 × 10 = 864,000, as the number of changes on
locks with the keys all of one size (that is, with one key of definite
size in all save the lengths of the steps). Moreover, the drill pins of
the locks and the pipes of the keys may be easily made of three
different sizes; and the number of changes will then be 864,000 × 3 =
2,592,000, as the whole series of changes which may be gone through with
this key. In smaller keys, the steps of which are capable of being
reduced only ten times, and the bolt-step only five times, the number of
combinations will be 720 × 10 × 6 × 5 × 3 = 648,000. On the other hand,
in larger keys, the steps of which can be reduced thirty times, and the
bolt-step twenty times, the total number of combinations will be 720 ×
30 × 6 × 20 × 3 = 7,776,000.”

These enormous numbers have been the cause of much of the wonderment
which the six-tumbler locks have excited; and, as we shall see further
on, the Bramah lock presents still more of the marvellous in respect to
this ringing of the changes.

[Illustration: fig. 31. Chubb lock, with detector and six tumblers.]

The construction and action of the Chubb lock may be further illustrated
by means of an engraving, fig. 31, in which _b_ is the bolt of the lock,
with a stump riveted to it marked _s_. The six tumblers are shewn
perspectively, the front or anterior one being marked _t_; they all move
on the centre-pin _a_, but are nevertheless perfectly distinct and
separate, to allow of being elevated to different heights. At _d_ is
shewn one end of a divided spring, the divisions being equal to the
number of tumblers, one to each, and so bent that each spring may press
upon its particular tumbler. At _e_ is the detector-spring, so placed
that a projecting piece in the hindmost tumbler shall be near it; this
tumbler having also fixed into it a stud or pin _p_. This being the
arrangement, especially in relation to the stump _s_ and the tumblers,
it follows that all the tumblers must be lifted to exact and regulated
heights in order that the stump may pass through the longitudinal slits
of the tumblers; unless it can do so, the bolt cannot be withdrawn. As
there are gaps or notches in each tumbler both above and below the
proper line of passage, and as there are no ordinary means of
ascertaining when any one tumbler is lifted too high or not high enough,
the safety of the lock is greatly increased by this uncertainty;
especially when it is considered that this uncertainty is multiplied
sixfold by the different modes in which the six tumblers are slotted.
If, through the insertion of a false key, or by any other cause, any one
of the tumblers be raised above its proper position, the detector spring
_e_ will catch the hindmost tumbler, and retain it so as to prevent the
bolt from passing; and thus, upon the next application of the true key,
it will be instantly felt that some one of the tumblers has been
overlifted, because the true key will not unlock it. To relieve the bolt
from this temporary imprisonment, the key must be turned the reverse
way, as for locking; all the tumblers will thus be brought to their
proper position, and allow the stump to enter the notches _n n´_; the
bevelled part of the bolt will then lift up the detector-spring, and
allow the hindmost tumbler to fall down into its proper place; and all
this being effected, the lock may be opened and shut in the ordinary
way. The pin _p_ is so adjusted that if any one of the tumblers--front,
back, or intermediate--be lifted too high, the pin will be lifted with
it, and will catch into the detector-spring, thus producing the result
just described.

[Illustration: fig. 32.

Key to Chubb’s lock.]

The key is represented in fig. 32. It has six steps, besides a terminal
step to act upon the bolt. The height of each step, or the distance to
which it extends from the pipe of the key, depends of course on the
height to which its corresponding tumbler is to be lifted; and it
matters not whether the steps of the key are adjusted to the slots of
the tumblers, or the slots to the steps, provided the agreement be
brought about. It is simply a matter of manufacturing convenience that
the key-steps are cut first and the tumbler-slots afterwards. We may
here remark that _bit_, or _bitt_, is the name given, somewhat
indefinitely, either to the whole flat part of a key, or to the small
stepped portions of it. The flat part was formerly termed the _web_ of
the key, probably from the _webbed_ appearance of the keys to complex
warded locks.

After the reading of Mr. Chubb’s paper before the Institution of Civil
Engineers, Mr. Owen narrated one or two circumstances connected with the
early history of Chubb’s lock. A convict on board one of the
prison-ships at Portsmouth dockyard, who was by profession a lock-maker,
and who had been employed in London in making and repairing locks for
several years, and subsequently had been notorious for picking locks,
asserted that he had picked with ease one of the best of Bramah’s locks,
and that he could pick Chubb’s locks with equal facility. One of the
latter was secured by the seals of the late Sir George Grey, the
Commissioner, and some of the principal officers of the dockyard, and
given to the convict, together with files and all the tools which he
stated were necessary for preparing false instruments for the purpose,
as also blank keys to fit the pin of the lock. A lock exactly the same
in principle was placed in his hands, that he might examine it and make
himself master of its construction. If he succeeded in opening the lock,
he was to receive a free pardon from the Government, and a reward of
100_l._ from Messrs. Chubb. After trying for two or three months to pick
the sealed lock--during which time, by his repeated efforts, he
frequently over-lifted the detector, which was as often re-adjusted for
his subsequent trials--he gave up the attempt. He stated that Chubb’s
were the most secure locks he had ever met with, and that it was
impossible for any man to pick or to open them with false instruments.

Mr. Owen further stated, that in order to compare the merits of Bramah’s
and Chubb’s locks, he had suggested a mechanical contrivance, which was
applied to one of Bramah’s six-spring padlocks belonging to the Excise.
It was hung upon a nail, in a vertical position, secure from lateral
oscillation. A self-acting apparatus was then applied, consisting of a
pipe with hexagonal grooves, and a stud or bit corresponding with the
division of the lock, and secured to it by a spring. In the grooves of
this pipe small slides were inserted, which pressed against the spring
keys of the lock; to these slides were attached levers, acted upon by
eccentrics, moved by a combination of wheels, whose teeth differed in
number so as to perform the permutation required for the different
depths of the spring keys, corresponding with those of the proper key to
the lock. The automaton machine was set in motion by a line working over
a barrel, and acted upon by a weight; and was thus left acting upon the
mechanism for a considerable time. At right angles to the pipe or false
key was attached a rod and weight; and when the notches in the spring
keys were brought in a line with the plane of the plate or diaphragm of
the lock, the rod and weight turned the false key, opened the lock, and
stopped the further motion of the automaton. In that state the slides
indicated the exact depth of the grooves in the proper key, and gave the
form of a matrix by which to make a key similar to the original one. The
automaton worked during a period varying from half an hour to three
hours, according to the state of permutation of the apparatus at the
moment of being applied, compared with that of the slides in the lock.
We confess that it is difficult to understand the action of this
automaton from Mr. Owen’s description. We imagine that the false notches
would effectually prevent the operation of the instrument, and openings
would be required on each slide to bring it back, so as to meet the
motions of the machine.

Mr. Owen did not state whether his apparatus had been successful with
one only of Bramah’s locks or with several; nor did he describe any
apparatus invented with the view to the picking of Chubb’s locks. He
stated, however, that in order to ascertain the effect of friction on
one of these last-named locks, it was subjected to the alternate
rectilinear motion of a steam-engine in Portsmouth dockyard, and was
locked and unlocked upwards of 460,000 times consecutively, without any
appreciable wear being indicated by a gauge applied to the levers and
the key, both before and after this alternate action. Mr. Owen concluded
by expressing his individual opinion that Chubb’s lock had never been
picked. “The detector was the main feature of its excellence; and
additional precaution, therefore, was only departing from its
simplicity, and adding to the expense, without any commensurate
advantage.”

In a subsequent chapter the degree of security afforded by various
descriptions of locks, and the obstacles which they present of being
picked, will come under notice; we therefore now proceed to describe
briefly a few other tumbler-locks, or application of the
tumbler-principle.

In Mr. Somerford’s lock, for which the Society of Arts gave a premium in
1818, an attempt was made to improve upon the ordinary action of
tumblers. In most such locks, all the tumblers must ascend, although to
different heights, before the stud of the bolt can pass through the
slots; “which arrangement,” says Mr. Somerford, “gives an opportunity of
introducing a nail, or a piece of stout wire, into the lock, and thus
raising the tumblers without the necessity of using the key.” In his new
lock, however, he made one lever to ascend while the other descended, by
a somewhat complicated arrangement of slotted plates above and below the
bolt. The key was so perforated as to be much endangered in respect to
strength.

In Davis’s lock there is a double chamber with wards on the side of the
key-hole. The key is inserted into the first chamber and turned a
quarter round; it is then pushed forward into the inner chamber, where
there is a rotating plate containing a series of small pins or studs,
which are laid hold of by the key. By turning the key, the plate is
moved round, the tumbler is raised, and the bolt is shot backwards and
forwards. This lock, which is somewhat expensive, is used to some extent
on Cabinet despatch-boxes.

The lock invented by Mr. Nettlefold is so constructed, that when the
bolt is shot out by the key, two teeth or quadrants are projected from
the sides of the bolt, which take a firm hold of the plate fixed on the
door-post or edge. This construction is said to answer well for
sliding-doors.

Mr. Alfred Ainger, in 1820, received a silver medal from the Society of
Arts for a draw-back spring latch, in which the objects proposed were
the two following--to render the lock more difficult of violation by a
pick than those ordinarily in use; and to apply to it a key of which no
ordinary person could take an impress, and which would be difficult of
access even in a workman’s hand. The key is very peculiar; its pipe
consists of three divisions, the section of the upper and lower
divisions being circular, and that of the middle division triangular;
the triangular portion is intended to give motion to some part of the
interior of the lock during the rotation of the key. There are collars
fixed on the extremity of the key, to act each on one tumbler; and there
are modes, by varying the arrangement of these collars on an octagonal
stem, to give something like a permutation to the number of variations
to which the action of the key may be subject. The notches or slots are
rather in the bolt than in the tumblers; and there are many
peculiarities in the general arrangement.

In a lock invented and patented by Mr. Parsons, the tumblers are of a
particular form, being hinged on a pivot at their centres, and working
into and out of two notches cut in the under side of the bolt. It must
be obvious that many variations in the adjustment of the tumblers of
locks might be made, without vitiating the principle on which the action
depends.

Many inventors have tried the use of an expanding web to the key, so
planned that if the step of the web be long enough to reach the tumbler,
it would be too long to pass through the key-hole; and therefore a
principle of safety would operate by enabling the key to adjust itself
at one moment to the size of the key-hole, and at another to the height
of the tumbler. Mr. Machin of Wolverhampton invented such a key in 1827.
The web of the key is movable on a countersunk pin, on which it can so
far slide as to be drawn one-eighth of an inch from the barrel. The
key-hole is of such a size as to admit the key only when the web is
pressed close up to the barrel. When the key in this state is
introduced, and is begun to be turned round, one of the notches in the
web works into a raised circular edge of steel, placed eccentrically
with regard to the lock-pin; so that as the key is turned, the web
becomes drawn out, and is at its greatest elongation when it arrives at
the tumblers: in the second half of its circular movement, the key
becomes contracted to its original dimensions, and can then be removed
from the lock.

Another mode of modifying the key has been introduced by Mr. Mackinnon,
the object being to enable any person to change at will the pattern or
arrangement of the movable parts of a lock and key; or to keep the key,
when not actually in use, in such a state as to render it unavailing to
any one but himself. It was a complex arrangement, which does not seem
to have come much into use.

The lock invented by Mr. Williams, in 1839, may be designated a
pin-lock, involving a principle analogous in many points to that of the
Egyptian lock. This lock has a series of pins which reach through the
cap, and are pressed to their places with a key like a comb or a
rake-head. On the inner end of each pin is a flat piece of steel, in
which is cut a notch for the passage of the bolt; but this passage is
not clear until the notches in all the pieces of steel are in a right
line. The pins are movable, and can be pushed either too far or not far
enough to bring about the coincidence of position in the notches; and on
this ground they are “double-acting.” Now the teeth of the key are of
irregular lengths, each having a length just suited for pushing the pin
to the proper depth: any other lengths of teeth would fail to open the
lock. There is a mechanism of springs and levers to shoot the bolt when
the pins in the plate are rightly adjusted. The arrangements in respect
to the key are singular and somewhat awkward. The teeth which lock the
bolt are not the same as those which unlock it, the user having to
change ends and adjust the bit to a socket-handle. This is one among
many examples in which a lock embodies several principles, the inventor
having set himself the task of combining the excellences of many diverse
locks.

In respect to the tumbler-locks generally, the simplicity of action, the
strength of construction, and the non-liability of disarrangement, have
given them a high place among safety-locks. The only danger seemed to
be, that any person once obtaining possession of the key could take an
impression from it, and thence form a key which would command the lock.
Attempts have been occasionally made to obviate this danger, by
supplying the key with movable bits which could be changed at pleasure,
so as to constitute any number of effectively different bits in
succession. But the locks being so constructed that the bolt could only
be moved when the tumblers were in a certain position, the owner was
placed in this predicament: that it was useless to alter the arrangement
of the bits in the key, unless the tumblers were altered in a
corresponding manner; and this would entail the removal of the lock from
the door, and the re-arrangement of the interior mechanism.

One of the great defects of tumbler-locks made previously to the last
ten years was, that the tumblers, when lying at rest in the lock,
presented at their _bellies_ or lower edges precisely the same
arrangement as the steps of the key. Indeed, in many locks of the
present day, a good idea of the form of the key may be gained by feeling
the bellies of the tumblers. The bellies are in fact cut out so as to
compensate for the circular motion of the key, to allow them to remain
at rest while the stump is passing through the gating. Even in
tumbler-locks of the best construction the tumblers will vibrate more or
less during the motion of the key; a defect which must be provided
against in adjusting the lock, or the stump will be caught in its
passage through the gating. Mr. Hobbs provides a simple remedy by
enlarging the back part of the gating, the effect of which is as
follows: when, in shooting back the bolt, as in unlocking, the key has
got to its highest point, the stump enters the narrow end of the gating;
but in shooting the bolt forward, as in locking, the stump enters the
gating before the key has got to its highest point, and to allow for the
slight vibratory motion of the tumblers during the passage of the stump,
the gating is widened. The usual method of adjustment is to alter the
forms of the bellies of the tumblers, thus greatly risking the security
of the lock, a defect which was clearly perceived by Bramah [see pp.
67-70], and was one of the reasons which induced him to construct locks
with slides instead of tumblers.

American locks on the tumbler-principle, and the relation which all such
locks bear to the Bramah lock, will be better understood after the
details of the following chapter.




CHAPTER VI.

THE BRAMAH LOCK.


The lock which was invented by the late Mr. Bramah deservedly occupies a
high place among this class of contrivances. It differs very materially
from all which has gone before it; its mechanical construction is
accurate and beautiful; its key is remarkable for smallness of size; and
the invention was introduced by the publication of an essay containing
much sensible observation on locks generally. The full title of this
essay runs thus: “A dissertation on the Construction of Locks.
Containing, first, reasons and observations, demonstrating all locks
which depend upon fixed wards to be erroneous in principle, and
defective in point of security. Secondly, a specification of a lock,
constructed on a new and infallible principle, which, possessing all the
properties essential to security, will prevent the most ruinous
consequences of house-robberies, and be a certain protection against
thieves of all descriptions.” A second edition of this _Dissertation_
was published in 1815; but the work is now extremely scarce, and hardly
attainable.

It is remarkable to observe the boldness and self-relying confidence
with which Mr. Bramah, some sixty years ago, declared that _all_ locks
were, up to that time, violable; he felt that this was strictly true,
and he hesitated not to give expression to his conviction. The following
is from his _Dissertation_:--

“It is observable that those who are taken in the desperate occupation
of house-breaking are always furnished with a number and variety of keys
or other instruments adapted to the purpose of picking or opening locks;
and it needs no argument to prove that these implements must be
essential to the execution of their intentions. For unless they can
secure access to the portable and most valuable part of the effects,
which in most families are deposited under the imaginary security of
locks, the plunder would seldom recompense the difficulty and hazard of
the enterprise; and till some method of security be adopted by which
such keys and instruments may be rendered useless, no effectual check or
opposition can be given to the excessive and alarming practice of
house-breaking.

“Being confident that I have contrived a security which no instrument
but its proper key can reach; and which may be so applied as not only to
defy the art and ingenuity of the most skilful workman, but to render
the utmost force ineffectual, and thereby to secure what is most valued
as well from dishonest servants as from the midnight ruffian, I think
myself at liberty to declare (what nothing but the discovery of an
infallible remedy would justify my disclosing), that all dependence on
the inviolable security of locks, even of those which are constructed on
the best principle of any in general use, is fallacious. To demonstrate
this bold and alarming proposition, I shall first state the common
principles which are applied in the art of lock-making; and by
describing their operation in instruments differently constructed, prove
to my intelligent readers that the best-constructed locks are liable to
be secretly opened with great facility; and that the locks in common use
are calculated only to induce a false confidence in their effect, and to
throw temptation to dishonesty in the way of those who are acquainted
with their imperfections, and know their inefficacy to the purpose of
security” (p. 5).

Tumblers had been so little thought of and used at the time Bramah
wrote, that his attention was almost exclusively directed to _warded_
locks. The mysterious clefts in a key, connected with some kind of
secret mechanism in the lock, had given the warded locks a great hold on
the public mind, as models of puzzlement and security; and it was to
shew that this confidence rested on a false basis, that he to a great
extent laboured. The following is his exposition of the principle and
the defects of the warded lock.

“Locks have been constructed, and are at present much used and held in
great esteem, from which the picklock is effectually excluded; but the
admission of false keys is an imperfection for which no locksmith has
ever found a corrective; nor can this imperfection be remedied whilst
the protection of the bolt is wholly confided to fixed wards. For if a
lock of any given size be furnished with wards in as curious and
complete a manner as it can be, those wards being necessarily expressed
on what is termed by locksmiths the bit or web of the key, do not admit
of a greater number of variations than can be expressed on that bit or
web; when, therefore, as many locks have been completed of the given
size as will include all the variations which the surface of the bit
will contain, every future lock must be the counterpart of some former
one, and the same key which opens the one will of course unlock the
other. It hence follows that every lock which shall be fabricated on
this given scale, beyond the number at which the capability of variation
ends, must be as subject to the key of some other lock as to its own;
and both become less secure as their counterparts become more numerous.
This objection is confirmed by a reference to the locks commonly fixed
on drawers and bureaus, in which the variations are few, and these so
frequently repeated, from the infinite demand for such locks, that, even
if it were formed to resist the picklock, they would be liable to be
opened by ten thousand correspondent keys. And the same observation
applies in a greater or less degree to every lock in which the
variations are not endless.

“But if the variation of locks in which the bolt is guarded only by
fixed wards could be multiplied to infinity, they would afford no
security against the efforts of an ingenious locksmith; for though an
artful and judicious arrangement of the wards, or other impediments, may
render the passage to the bolt so intricate and perplexed as to exclude
every instrument but its proper key, a skilful workman having access to
the entrance will be at no loss to fabricate a key which shall tally as
perfectly with the wards as if the lock had been open to his inspection.
And this operation may not only be performed to the highest degree of
certainty and exactness, but is conducted likewise with the utmost ease.
For the block or bit, which is intended to receive the impression of the
wards, being fitted to the keyhole, and the shank of the key bored to a
sufficient depth to receive the pipe, nothing remains but to cover the
bit with a preparation which, by a gentle pressure against the
introductory ward, may receive its impression, and thus furnish a
certain direction for the application of the file. The block or bit
being thus prepared with a tally to the first ward, gains admission to
the second; and a repetition of the means by which the first impression
was obtained, enables the workman to proceed, till by the dexterous use
of his file he has effected a free passage to the bolt. And in this
operation he is directed by an infallible guide; for, the pipe being a
fixed centre on which the key revolves without any variation, and the
wards being fixed likewise, their position must be accurately described
on the surface of the bit which is prepared to receive their impression.
The key therefore may be formed and perfectly fitted to the lock without
any extraordinary degree of genius or mechanical skill. It is from hence
evident that endless variations in the disposition of fixed wards are
not alone sufficient to the purpose of perfect security. I do not mean
to subtract from the merit of such inventions, nor to dispute their
utility or importance. Every approach towards perfection in the art of
lock-making may be productive of much good, and is at least deserving of
commendation; for if no higher benefit were to result from it, than the
rendering difficult or impossible to many that which is still
practicable and easy to a few, it furnishes a material security against
those from whom the greatest mischiefs and dangers are to be
apprehended.”

There can be little doubt, in the present day, that Bramah did not
over-rate the fallacies embodied in the system of wards for locks. He
was sufficiently a machinist to detect the weak points in the ordinary
locks; and, whatever may have been his over-estimate of his own lock
(presently to be described), he was certainly guilty of no injustice to
those who had preceded him; for their locks were substantially as he has
described them. To understand the true bearings of his Dissertation too,
we must remember that housebreaking had risen to a most daring height in
London at the time he wrote (about the middle of the reign of George
III.); and men’s minds were more than usually absorbed by considerations
relating to their doors and locks.

Mr. Bramah, after doing due justice to the ingenuity of Barron’s lock,
in which, if the tumbler be either _over_ lifted or _under_ lifted the
lock cannot be opened, pointed out very clearly the defective principle
which still governed the lock. “Greatly as the art is indebted to the
ingenuity of Mr. Barron, he has not yet attained that point of
excellence in the construction of his lock which is essential to perfect
security. His improvement has greatly increased the difficulty but not
precluded the possibility of opening his lock by a key made and
obtained as above described (by a wax impression on a blank key); for an
impression of the tumblers may be taken by the same method, and the key
be made to act upon them as accurately as it may be made to tally with
the wards. Nor will the practicability of obtaining such a key be
prevented, however complicated the principle or construction of the lock
may be, whilst the disposition of its parts may be ascertained and their
impression correctly taken from without. I apprehend the use of
additional tumblers to have been applied by Mr. Barron as a remedy for
this imperfection.” Mr. Bramah thought that Barron had a perception of a
higher degree of security, but had failed to realise it; because, by
giving a uniform motion to the tumblers, and presenting them with a face
which tallies exactly with the key, they still partake in a very great
degree of the nature of fixed wards, and the security of the lock is
thereby rendered in a proportionate degree defective and liable to
doubt.

To shew how this insecurity arises, Mr. Bramah illustrates the matter in
the following way: “Suppose the key with which the workman is making his
way to the bolt to have passed the wards, and to be in contact with the
most prominent of the tumblers. The impression, which the slightest
touch will leave on the key, will direct the application of the file
till sufficient space is prepared to give it a free passage. This being
accomplished, the key will of course bear upon the tumbler which is most
remote; and being formed by this process to tally with the face which
the tumblers present, will acquire as perfect a command of the lock as
if it had been originally made for the purpose. And the key, being thus
brought to a bearing on all the tumblers at once, the benefit arising
from the increase of their number, if multiplied by fifty, must
inevitably be lost; for, having but one motion, they act only with the
effect of one instrument.”

It is worthy of notice, that even while thus shewing the weak points of
the Barron lock, Mr. Bramah seems to have had in his mind some
conception of infallibility or inviolability attainable by the lock in
question. After speaking of the defect arising from the bad arrangement
of the tumblers, he says: “But nothing is more easy than to remove this
objection, and to obtain perfect security from the application of Mr.
Barron’s principle. If the tumblers, which project unequally and form a
fixed tally to the key, were made to present a plane surface, it would
require a separate and unequal motion to disengage them from the bolt;
and consequently no impression could be obtained from without that would
give any idea of their positions with respect to each other, or be of
any use even to the most skilful and experienced workman in the
formation of a false key. The correction of this defect would rescue the
principle of Mr. Barron’s lock, as far as I am capable of judging, from
every imputation of error or imperfection; and, as long as it could be
kept unimpaired, would be a perfect security. But the tumblers, on which
its security depends, being of slight substance, exposed to perpetual
friction--as well from the application of the key as from their own
proper motion--and their office being such as to render the most
trifling loss of metal fatal to their operation, they would need a
further exertion of Mr. Barron’s ingenuity to make them durable.”

It may perhaps be doubted whether the principle of Bramah’s lock is not
more clearly shewn in the original constructed by him than in that of
later date. In appearance it is totally different, but the same
pervading principle is observable in both; and the cylinder lock can
certainly be better understood when this original flat lock has been
studied. The annexed woodcut is taken from the first and very scarce
edition of Mr. Bramah’s _Dissertation_; the description is somewhat more
condensed, but perhaps sufficient for the purpose.

[Illustration: fig. 33. Bramah’s first model.]

The lock is supposed to be lying flat, with the bolt B half-shot. Ranged
somewhat diagonally are six levers, turning on a horizontal joint or
pivot at A, each lever having a slight extent of vertical motion
independent of the others. Each lever rests on a separate spring of
sufficient strength to sustain its weight, or, if depressed by a
superior force, to restore it to its proper position when the force is
withdrawn. F is a curved piece of metal, pierced with six grooves or
passages; these grooves are exactly equal in width to the thickness of
the levers, but are of sufficient depth to allow the levers a free
motion in a perpendicular direction. The ends of the levers are inserted
in these grooves, and have this freedom of motion, whether lifted by the
elastic power of the springs or depressed by a weight from above. In the
bolt B is a notch to receive a peculiarly-shaped lever, which shoots or
withdraws the bolt according as it traverses to the right or the left.
This lever, the six long levers, the springs beneath them, the bent
piece F, and the pivot, all alike are fixed to a circular platform P,
which turns on a centre; so that if any force can make this platform
turn partially round, the bolt must be shot or unshot by the lever which
works in the notch. The six long levers are the contrivances whereby
the platform shall _not_ be allowed to turn until the proper moving
agent (the key) shall have been applied, the plate _p_ being one of the
assistants in this obstruction. This plate, which is hollow underneath,
has six notches in one of its edges; the points of the levers catch into
these notches; and while so caught, the levers cannot move horizontally,
and all the machinery is at a stand-still. To enable the key to set the
mechanism in action, other contrivances are necessary. Each lever has a
notch at its extreme end, and the six are notched very irregularly in
respect one to another. These notches must be brought all into one
plane, to enable the levers to pass horizontally out of the notches in
the plate, in the same way as the two prongs of a fork might traverse
one above and the other below the blade of a knife; and when the
lever-notches are in this position, all in one plane and in the plane of
the plate, the levers can be moved, and with it the stump which shoots
the bolt. To ensure this due pressing down of the levers, a key is used
such as is shewn in the cut, having six steps or bits to correspond with
the six levers; this key, put upon the pin K, presses down all the
levers to the exact distance necessary for bringing their notches into
one plane, viz. the plane of the plate; the key then being turned round
turns the movable platform P, and shoots the bolt. It is evident at a
glance, that unless the various steps of the key are so cut, that each
shall press down its own lever to the proper extent, the ends of the
levers cannot pass the notches in the plate, and the bolt can neither be
locked nor unlocked.

It may be well to give Bramah’s own words in relation to this lock: “I
may safely assert that it is not in art to produce a key or other
instrument by which a lock constructed on this principle can be opened.
It will be a task, indeed, of great difficulty, even to a skilful
workman, to fit a key to this species of lock, though its interior face
were open to his inspection; for the levers being raised by the
subjacent springs to an equal height present a _plane_ surface, and
consequently convey no direction that can be of any use in forming a
tally to the _irregular_ surface which they present when acting in
subjection to the proper key. Unless, therefore, a method be contrived
to bring the notches on the ends of the levers in a direct line with
each other, and _to retain them in that position till an exact
impression of the irregular surface which the levers will then exhibit
can be taken_, the workman will in vain attempt to fit a key to the
lock, or by any effort of art to move the bolt. And when it is
considered that this process will be greatly impeded, and may perhaps be
entirely frustrated, by the action of the springs, it must appear that
great patience and perseverance, as well as great ingenuity, will be
required to give any chance of succeeding in the attempt. I do not state
this circumstance as a point essential or of any importance to the
purpose of the lock, but to prove more clearly what I have before
observed upon its principle and properties; for if such difficulties
occur to a skilled workman, as to render it almost, if not altogether
impracticable to form a key when the lock is open to his inspection and
its parts accessible to his hand, it pretty clearly demonstrates the
impossibility of accomplishing it when no part of the movement can be
touched or seen.”

It is evident that Mr. Bramah had his thoughts directed to that mode of
picking locks which depends on taking impressions of the moving parts,
rather than to the _mechanical_ or _pressure_ method which has been
developed in later times. There can be little doubt that a lock was, to
his mind, a beautiful and admirable machine, far elevated above the
level of mere blacksmith’s work; and his name will ever be associated
with what may be termed the philosophy of lock-making.

After the model-lock, which has just been described, was constructed,
and found to corroborate the idea which was working in Mr. Bramah’s
mind, he proceeded to the construction of his barrel or cylinder-lock,
embracing similar elements placed in more convenient juxta-position. In
his Essay he gives an engraving to illustrate the principle on which his
lock acts, rather in the manner of a diagram than as depicting any lock
actually made; his main object being to impart a clear notion of the
action of the slides which form such a distinguishing feature in his
lock.

[Illustration: fig. 34. Diagram to illustrate the Bramah lock.]

Viewed in this sense, therefore, simply as an illustrative diagram, the
annexed cut may represent the action of the safety slides. B is a
sliding bar or bolt, having a power of longitudinal motion in the frame
F. This frame has six notches cut on each of its long sides, the two
series being exactly opposite each other; and there are six similar
notches cut in the bolt B. The concurrent effect of all these eighteen
notches is, that the six slides _a b c d e f_ can move freely up and
down across the bolt. When the slides are thus placed, the bolt cannot
move, and may in this case be considered to be locked. There are six
clefts or notches in the six slides, one to each (1, 2, 3, 4, 5, 6); and
until all these are brought in a right line, the bolt cannot move
through them. If a tally or key be prepared, as shewn at T in the lower
part of the cut, with six projections, and if these projections thrust
up the six slides till their clefts rise to the plane of the bolt, then
can the bolt be withdrawn or the lock opened. This serves to illustrate
the relation between the slides and the key, as carried out in the way
now to be described.

One peculiarity of the Bramah lock is, that from the essential part of
the apparatus being a barrel or cylinder, much of the working can be
conducted in the lathe; and this has given a beauty to the details
generally and deservedly admired. Mr. Bramah, when he worked out the
theory of his lock, resolved to discard altogether the use of fixed
wards, and also the use of tumblers working on a pivot at one end;
substituting in their stead a system of slides, working in a very novel
way. The body of a Bramah lock may be considered as formed of two
concentric brass barrels, the outer one fixed, and the inner rotating
within it. The inner barrel has a projecting stud, which, while the
barrel is rotating, comes in contact with the bolt in such a way as to
shoot or lock it; and thus the stud serves the same purpose as the bit
of an ordinary key, rendering the construction of a bit to the Bramah
key unnecessary. If the barrel can be made to rotate to the right or
left, the bolt can be locked or unlocked; and the problem is, therefore,
how to ensure the rotation of the barrel. The key, which has a pipe or
hollow shaft, is inserted in the keyhole upon the pin, and is then
turned round; but there must be a very nice adjustment of the mechanism
of the barrel before this turning round of the key and the barrel can be
ensured. The barrel has an external circular groove at right angles to
the axis, penetrating to a certain depth; and it has also several
_internal_ longitudinal grooves, from end to end. In these internal
grooves thin pieces of steel are able to slide, in a direction parallel
with the axis of the barrel. A thin plate of steel, called the
locking-plate, is screwed in two portions to the outer barrel,
concentric with the inner barrel; and at the same time occupying the
external circular groove of the inner barrel; this plate has notches,
fitted in number and size to receive the edges of the slides which work
in the internal longitudinal grooves of the barrel. If this were all,
the barrel could not revolve, because the slides are catching in the
grooves of the locking-plate; but each slide has also a groove,
corresponding in depth to the extent of this entanglement; and if this
groove be brought to the plane of the locking-plate, the barrel can be
turned, so far as respects that individual slide. All the slides must,
however, be so adjusted that their grooves shall come to the same plane;
but as the notch is cut at different points in the lengths of the
several slides, the slides have to be pushed in to different distances
in the barrel, in order that this juxta-position of notches may be
ensured. This is effected by the key, which has notches or clefts at the
end of the pipe equal in number to the slides, and made to fit the ends
of the slides when the key is inserted; the key presses each slide, and
pushes it so far as the depth of its cleft will permit; and all these
depths are such that all the slides are pushed to the exact position
where their notches all lie in the same plane; this is the plane of the
locking-plate, and the barrel can be then turned.

[Illustration: fig. 35. Exterior of a Bramah lock.]

This is the principle which Mr. Bramah adopted; and we have now to trace
it, step by step, by means of illustrative details. Fig. 35 represents
the exterior of a box or desk lock, one among many varieties which the
Bramah lock presents. A A shews the bolt, formed something like two
hooks rising out of a bar of metal, which bar has a backward and forward
motion upon the plate B B. The upper edge of this plate is turned over
at right angles, forming a small horizontal surface through which two
openings are cut to receive the two hooked portions of the bolt. The
movements of the bolt are otherwise guided by the edges of square holes
through which it works; the holes being made in the edge-pieces of the
lock, riveted to the main plate. The bolt is further prevented from
rising out of its place by means of a plate of metal C, which is secured
to the edge-pieces by two screws 1, 1, and by two steadying pieces. This
plate has on its surface a cylindrical projection D, which contains in
effect all the working mechanism of the lock. The pins 4 4 are employed
for securing a plate, which we shall have to describe presently. When
such a lock is fixed upon a desk or box, the portion _D_ projects to a
small distance through a hole in the wood-work, forming in itself a very
neat escutcheon, with a key-hole in the centre.

[Illustration: fig. 36. Details of the Bramah lock.]

[Illustration: fig. 37. The slides.]

So much for the exterior. We must now proceed to examine the interior of
the lock, especially the part contained within the cylinder. In fig. 36,
for convenience of arrangement, the several parts are exhibited
separately, and as if the plane of the lock were horizontal, with the
key acting vertically. The essential part of the mechanism is a barrel
or cylinder _E_, pierced or bored with a cylindrical hole down its
centre. The inside of the bore has six narrow grooves, cut parallel with
the axis, and in the direction of radii; the grooves are not cut through
the thickness of the cylinder, but leave sufficient substance of metal
for strength. In every groove is fitted a steel slide of peculiar form,
such as is shewn at _a´ a´_ in fig. 37. Each slide is split in its
thickness (seen in section), so that it may move up and down in its
groove with a slight friction, and thereby not fall simply by its own
weight. Each slide has three small notches (3, 2, 3´), the use of which
will presently appear. Reverting to fig. 36, the lower part of the
opening through the cylinder _E_ is closed by a circular plate of metal,
fixed to it by two screws; this plate is represented at _F_, in the
lower part of the figure. This plate has a vertical pin rising from its
centre (also seen at _b_, fig. 39), and serving as a key-pin on which
the pipe of the key may work or slide; and it has also a short circular
stud _c_ projecting from its under side, and fitted to enter into a
curved opening in the bolt presently to be described.

The point to be now borne in mind is this, that if the cylinder _E_
turns round, the plate _F_ will also turn round, and with it the stud
_c_; and as this stud works into the peculiarly formed cavity _d_ in a
portion of the bolt (fig. 38), it causes the bolt to be shot backwards
or forwards. Now, in order to prevent this rotating of the cylinder
unless the proper key be employed, the following mechanism is
introduced: the cylinder has a groove cut round its circumference at _e
e_, extending sufficiently near to the internal bore to produce the
desired effect without too much weakening the metal. Into this notch is
introduced the thin circular plate of metal _f f_, it being divided into
two halves for this purpose; and when so placed, it occupies the
position shewn by the dotted portion _e e_. When this plate is screwed
to the case of the lock by the screws 4, 4, it cannot of course turn
round; but the cylinder itself will or will not turn round according to
the position of the slides. The plate _f f_ has six notches, 5, 5, 5,
&c. in the inner edge or circle; so adjusted that, when the plate is in
its place, the slides _a a_ can move up and down. The cylinder cannot
move round in a circle without carrying the slides with it; and these
cannot so move unless they are all depressed to such exact distances in
their respective grooves, that the deep notch of each slider (shewn at 2
in fig. 37) shall come into the plane of the circular plate: when all
are so brought, the cylinder can be turned. If any one of the slides be
pressed down either too low or not low enough, this turning of the
cylinder cannot be effected, because the slides will be intersected by
the edges of the notches 5, 5; and it is the office of the key,
therefore, to press all the six slides down to the exact distances
required. When the slides are not pressed upon by the key, they are
forced upwards to the top of the cylinder by a spiral spring 6, coiled
loosely round the pin _b_; this pressure forces up a small collet, 7, on
which the upper part of the slides rest by a sort of step.

[Illustration: fig. 38. The bolt.]

The first locks were made with a separate and independent spring to each
slide; but it is a very great improvement, the introduction of one
common spring to raise up the whole number; because if a person attempts
to pick the lock by depressing the slides separately by means of any
small pointed instruments, and by chance brings two or more of them to
the proper depth for turning round, should he press any one too low, it
is difficult to raise it again without relieving the spring 6, which
immediately throws the whole number of slides up to the top, and
destroys all that had been done towards picking the lock. Another
improvement of this lock, and one which very much increased the
difficulty of picking, and its consequent security, was the introduction
of false and deceptive notches cut in the sliders, as seen at 3, 3. It
was found that in the attempt to pick this lock, an instrument was
introduced by the keyhole to force the cylinder round. At the same time
that the slides were depressed by separate instruments, those slides
which were not at the proper level for moving round were held fast by
the notches 5, 5 in the plate _f f_ bearing against their sides; but
when pressed down to the proper level, or till the notch 2 came opposite
_f f_, they were not held fast, but were relieved. This furnished the
depredator with the means of ascertaining which slides were pressed low
enough, or to the point for unlocking. The notches 3, 3 in the slides
are sometimes cut above the true notch 2, sometimes below, and at other
times one on each side (one above and one below); they are not of
sufficient depth to allow the cylinder to turn round, but are intended
to mislead any one who attempts to pick, by his not knowing whether it
is the true notch or otherwise, or even whether the slider be higher or
lower than the true notch.

We have not yet sufficiently described the key of the Bramah lock. One
merit of the lock is the remarkable smallness of the key, which renders
it so conveniently portable. The key, as shewn in the upper part of the
figure, has six notches or clefts at the end of its pipe or barrel;
these clefts are cut to different depths, to accord with the proper
extent of movement in the slides. There is a small projection, 10, near
the end of the pipe, fitted to enter the notch D in the cylinder; this
forces the cylinder round when the parts are all properly adjusted. The
bolt of the lock, when properly shot or locked, is prevented from being
forced back by the stud _c_ on the bottom, F, of the cylinder coming
into a direct line with its centre of motion, as shewn in fig. 39; in
this position no force, applied to drive the bolt back, would have any
tendency to turn the cylinder round.

[Illustration: fig. 39. Section of the Bramah cylinder.]

To facilitate the comprehension of this very curious and beautiful
mechanism, the cylinder is shewn in section in the annexed fig. 39, the
same letters and figures of reference being used as before. In the whole
of this description we have spoken of six slides, and six only; but
Bramah locks may be, and have been, constructed with a much larger
number.

There have been several attempts made to modify the action of Bramah’s
lock, or to combine this action with that of some other inventor. It
will suffice to describe one of these. The lock invented by Mr. Kemp of
Cork, and for which a patent was obtained in 1816, is called by him the
_Union_ lock, as combining the principles of Barron’s and Bramah’s
locks. It contains two, three, or more sliders or tumblers, operated
upon by two, three, or more concentric tubes. These concentric tubes are
of different lengths, and are placed inside the barrel of the key; so
that the barrel may, in fact, be conceived to consist of a series of
concentric tubes. These tubes are made of such respective lengths as to
push back the tumblers, sliders, or pins which detain the bolt; and this
to the precise extent that will bring certain notches in all the sliders
to the position which will allow the bolt to pass. The inventor gives
this lock its distinctive appellation because it combines something of
the pushing motion which Bramah gives to his key, with something of the
tumbler-motion observable in Barron’s locks. The principle of safety is
considered here to rest chiefly on the extreme difficulty of imitating
the key.

Mr. Bramah calculates the number of changes of position which the slides
of his lock are capable of assuming before the right one would be
attained. “Let us suppose the number of levers, slides, or other
movables by which the lock is kept shut, to consist of twelve, all of
which must receive a different and distinct change in their position or
situation by the application of the key, and each of them likewise
capable of receiving more or less than its due, either of which would be
sufficient to prevent the intended effect. It remains, therefore, to
estimate the number producible, which maybe thus attempted. Let the
denomination of these slides be represented by twelve arithmetical
progressionals; we find that the ultimate number of changes that may be
made in their place or situation is 479,001,600; and by adding one more
to that number of slides, they would then be capable of receiving a
number of changes equal to 6,227,020,800; and so on progressively, by
the addition of others in like manner to infinity. From this it appears
that one lock, consisting of thirteen of the above-mentioned sliders,
may (by changing their places only, without any difference in motion or
size,) be made to require the said immense number of keys, by which the
lock could only be opened under all its variations.”




CHAPTER VII.

AMERICAN LOCKS.


The lock-manufacture in America has undergone some such changes as in
England. The insufficiency of wards to the attainment of security has
been for many years known; and the unfitness of even tumblers to attain
this end, without auxiliary contrivances, has been fully recognised for
a dozen years back. In this, and in other mechanical arts, the American
machinists depended primarily on the invention of the artisans in the
mother country, rather than on those of any continental European state.
But the development of the art in the United States has not been wanting
in originality; the varieties of locks have been very numerous, and many
of them exceedingly ingenious. It is not necessary, however, to describe
or depict any of those of simple form. The warded locks of different
countries very much resemble each other; the intricate warded locks
made in France in the last century have long fallen into disuse, in
consequence of the general conviction that no arrangement of wards,
however intricate, can afford the degree of security required in a good
lock. It will be more to the purpose, therefore, to proceed at once to a
notice of those American locks which, during the last few years, have
acquired some celebrity; first, however, noticing one of older date.

Stansbury’s lock, invented in the United States about forty years ago,
may be regarded as a modification of the Egyptian lock. It had a bolt,
case, and key-hole somewhat similar to those of modern locks; but there
were peculiarities of construction in other respects. There was a
revolving plate, pierced with a series of holes, and having a bit or pin
which moved the bolt. On the lock-case were a series of springs, each
having a pin at one end; and the arrangement was such that, when the
bolt was locked or unlocked, each pin would be pressed into some one of
the holes. Like as in the Egyptian lock (figs. 1 to 4), each pin had to
be pushed out, and all of them simultaneously, to allow the plate to
turn and move the bolt. The key was made with a barrel and bit; and on
the front end of the bit was a series of pins corresponding in position
with the holes in the plate. The mode of locking or unlocking was as
follows: the key was inserted in the key-hole, and turned to a certain
position; it was then pressed in with some force, until the pins on the
key met those in the plate; when the latter, yielding to the pressure,
left the plate free to turn and move the bolt. Modifications of the
Egyptian lock, more or less resembling this, have been brought out in
some variety on both sides of the Atlantic; but scarcely any have
equalled in simplicity the curious wooden relic of by-gone ingenuity in
the art of lock-making.

A lock made a few years ago by Mr. Yale, in the United States, somewhat
resembles the Bramah lock in having a cylinder or barrel, or rather two
concentric cylinders, one working within the other. These cylinders are
held together by pins which pass through them both into the key-hole. On
the back of the inner cylinder is a pin that fits into a slot in the
bolt, and moves it whenever the cylinder is turned. The pins that hold
the cylinders together are each cut in two; the pieces of the various
pins differing in lengths as irregularly as possible. The key is so
peculiarly formed, that, on inserting it in the key-hole, it thrusts the
pins radially outwards; each pin being pushed just so far that the joint
of the pin shall coincide with the joint between the two cylinders. The
inner cylinder can then be turned, by which the bolt is locked or
unlocked. If, by the use of a false key, any pin be pushed in too far,
it will be as ineffectual in opening the lock as if it were not thrust
in far enough; and some of these locks having been made with as many as
forty pins, the chances are very numerous against the right combination
being hit upon. There is a combination of something like the Egyptian
with something like the Bramah lock, here attempted.

One of the principal constructions adopted in America a few years back
for bank-locks is that of Dr. Andrews of Perth Amboy, in New Jersey. It
was up to that time (1841) believed that the best locks, both of England
and America, were proof against any attempts at picking derived from
knowledge obtained by inspection through the key-hole; but there still
remained the danger that the sight of the true key, or the possession
thereof, for only a few minutes, would enable a dishonest person to
produce a duplicate. It was to contend against this difficulty that Dr.
Andrews directed his attention; and he sought to obtain the desired
object by constructing a lock, the interior mechanism of which could be
changed at pleasure. The lock of his invention is furnished with a
series of tumblers and a detector. The tumblers are susceptible of being
arranged in any desired order; and the key has movable bits which can be
arranged so as to correspond with the tumblers. When the lock is fixed
in its place, no change can be made in the tumblers, and consequently
only one arrangement of the bits of the key will suit for the shooting
and withdrawing of the bolt. The owner can, however, before the fixing
of the bolt, adopt any arrangement of tumblers and bits which he may
choose. But though the tumblers cannot be actually re-arranged in any
new order within the lock while the latter is fixed, yet by an ingenious
contrivance the tumblers can be so acted upon as to render the lock
practically different from its former self. The purchaser receives with
his lock a series of small steel rings, each ring corresponds in
thickness with the thickness of some one of the bits of the key; so
that, by suitable adjustment, any one of the bits may be removed from
the key, and a ring be substituted in its place. The effect of this
substitution is, that the particular tumbler which corresponds with the
ring is not raised by it; it is drawn out with the bolt, as if it were
part of the bolt itself. Supposing the lock to be locked by this means,
the original key would not now unlock it; for one of the tumblers has
now been displaced, and can only be re-adjusted by the same ring which
displaced it. If an attempt be made to open the lock by the original
key, or by the key in its original adjustment, a detector is set in
action, which indicates that a false key or other instrument has been
put into the lock. One, or more than one, of the bits may be removed
from the key, and rings be substituted, and consequently one or more of
the tumblers may be disturbed in this peculiar way; so that the lock may
change its character in all those permutating varieties which are so
observable in most “safety-locks.” The shape of the tumblers is, of
course, such as to facilitate this action; they have each an elongated
slot, and also two notches; when a tumbler is raised by one of the bits
of the key, one of the notches closes around a stump fitted into the
case of the lock, and prevents the tumbler from being moved onward with
the bolt; but when a ring has been substituted for a bit on the key, the
tumbler cannot be raised at all; it is carried onward by a stump on the
bolt.

Dr. Andrews is also the inventor of a lock which he terms the
_snail-wheel lock_. In this lock a series of revolving discs, or wheels,
taking the place of the tumblers, are mounted on a central pin, on which
the pipe of the key is inserted. Each disc has a piece cut out of it,
into which the bit of the key enters, and in turning round moves the
discs according to the various lengths of the steps on the key. On the
outer edge of each disc is a notch, and by the turning of the key all
these notches are brought into a line, so that a moveable tongue, or
_toggle_, attached to the bolt, falls into the notches; the key is then
turned the reverse way, by which means the bolt is projected.

About the time when Dr. Andrews invented his first lock, Mr. Newell, of
the firm of Day and Newell of New York, constructed a lock which
possessed the same distinctive peculiarity as that of Andrews, viz. that
the key might be altered any number of times without rendering it
necessary to remove the lock or change its internal mechanism. This was
brought about, however, in a different manner. Instead of having, as in
the Andrews lock, a two-fold movement to every tumbler, Mr. Newell
employed two sets of tumblers, the one set to receive motion from the
other, and having different offices to fill, to be acted upon by the key
in respect to the first series, and to act upon the bolt in respect to
the second. Calling these two sets _primary_ and _secondary_, the action
of the lock may be briefly described as follows. A primary tumbler being
raised to the proper height by the proper bit in the key, raises the
corresponding secondary tumbler; the secondary tumbler is held up in a
given position during the locking, while the primary becomes pressed by
a spring into its original position. It results from this arrangement
that the bolt cannot be unlocked until the primary tumbler has been
raised to the same height as before, so as to receive the tongue of the
secondary tumbler. And as this is the case in respect to any one primary
and its accompanying secondary tumblers, so is it the case whether each
set comprises four, five, or any other number. The key may be altered at
pleasure, and will in any form equally well shoot the bolt; but the lock
can only be unfastened by that arrangement of key which fastened it.

It is, however, desirable to trace the course of improvements more in
detail, because every successive change illustrates one or other of the
several properties required in a good lock. Messrs. Day and Newell’s
lock was not finally brought to an efficient form without many attempts
more or less abortive. Mr. Newell conceived the idea of applying a
second series of tumblers, so placed as to be acted on by the first
series. Each of these secondary tumblers had an elongated slot, such
that a screw could pass through all of them; the screw having a clamp to
overlap the tumblers on the inside of the lock. The head of the screw
rested in a small round hole on the back of the lock, so placed as to
form a secondary key-hole, to which a small key was fitted. There was
thus a double system of locking, effected in the following way: when the
large key had been applied, and had begun to act on the primary
tumblers, the small key was used to operate on the clamp-screw, and thus
bind all of the secondary tumblers together, ensuring their position at
the exact heights or distances to which the primary key had caused them
to be lifted. The bolt was then free to be shot, and the first series of
tumblers reverted to their original position.

But such an arrangement has obvious inconveniences. Few persons would
incur the trouble of using two keys; and besides this, there were not
wanting certain defects in the action and reaction of the several parts;
for if the clamp-screw were to be left unreleased, the first series of
tumblers would be upheld by the second series in such a way that the
exact impression of the lengths of the several bits of the key could be
obtained through the key-hole while the lock was unlocked or the bolt
unshot. To remedy one or both of these evils was the next object of Mr.
Newell’s attention. He made a series of notches or teeth in each of the
secondary tumblers, corresponding in mutual distance with the steps or
bits of the key; and opposite these notched edges he placed a dog or
lever, with a projecting tooth suitable to fall into the notches when
adjusted properly in relation to each other. When the key was used, the
primary tumblers were raised in the usual way, and acted on the
secondary tumblers; these latter were so thrown that the dog-tooth
caught in the notches and held them fast, thereby rendering the same
service as the clamp-screw and the small key in the former arrangement.
No other relative position of the bits of the key could now unlock the
lock.

Still, improvement as it was, this change was not enough; Mr. Newell
found that his lock, like all the locks that had preceded it, was
capable of being picked by a clever practitioner; and candidly admitting
the fact, he sought to obtain some new means of security. He tried what
a series of complicated wards would do, in aid of the former mechanism;
but the result proved unsatisfactory. His next principle was to provide
a number of false notches on the abutting parts of the primary and
secondary tumblers, with alterations in other parts of the apparatus.
The theory now depended upon was this, that if the bolt were subjected
to pressure, the tumblers would be held fast by false notches, and could
not be raised by any lock-picking instrument. To increase the security,
a steel-curtain was so adjusted as to cover, or at least protect, the
key-hole. Great anticipations were entertained of this lock, but they
were destined to be negatived. A clever American machinist, Mr. Pettit,
accepted Messrs. Day and Newell’s challenge (500 dollars to any one who
could pick this lock); he succeeded in picking the lock, and thus won
the prize.

Once again disappointed, Mr. Newell re-examined the whole affair, and
sought for some new principle of security that had not before occurred
to him. He had found that, modify his lock how he might, the sharp-eyed
and neat-fingered mechanician could still explore the interior of the
lock in such a way as to find out the relative positions of the
tumblers, and thus adapt their means to the desired end. How, therefore,
to shut out this exploration altogether became the problem; how to make
a lock, the works of which should be _parautoptic_--to coin a word from
the Greek, which should signify _concealed from view_. The result of his
labours was the production of the American bank-lock now known by that
name. The details of this lock may now conveniently be given.

[Illustration: fig. 40. The American Parautoptic lock; bolt unshot.]

[Illustration: fig. 41. The same with the bolt shot.]

In fig. 40 the lock is represented in its unlocked state, with the cover
or top-plate removed; the auxiliary tumbler and the detector-plate are
also removed. In fig. 41 it is represented as locked, with the cover and
the detector-plate also removed, and the auxiliary tumbler in its place.
In these two figures, the same letters of reference apply to the same
parts, unless otherwise stated. B B is the bolt; T¹ are the first series
of movable slides or tumblers; _s_ shews the tumbler-springs; T² the
secondary series of tumblers; and T³ the third or intermediate
series--these latter coming between the first and secondary series; P P
are the separating plates between the several members of the first
series of tumblers; _s_¹ are the springs for lifting the intermediate
tumblers. On each of the secondary tumblers T² is a series of notches,
corresponding in mutual distance with the difference in the lengths of
the movable bits of the key. It thence happens that, when the key is
turned in the lock to lock it, each bit raises its proper tumbler, so
that some one of these notches shall present itself in front of the
tooth _t_ in the dog or lever L L. When the bolt B is projected by the
action of the key, it carries with it the secondary tumblers T², and
presses the tooth _t_ into the notches; in so doing, it withdraws the
tongues _d_ from between the jaws _j j_ of the intermediate tumblers T³,
and allows the first and intermediate tumblers to fall to their original
position. By the same movement, the secondary tumblers T² become held in
the position given to them by the key, by means of the tooth _t_ being
pressed into the several notches, as shewn in the closed state of the
lock (fig. 41). Now let us see what results if any attempt be made to
open the lock with any arrangement of key but that by which it has been
locked. In such case, the tongues _d_ will abut against the jaws _j j_,
preventing the bolt from being withdrawn; and should an attempt be made
to ascertain which tumbler binds and requires to be moved, the
intermediate tumbler T³ (which receives the pressure), being behind the
iron wall I I, which is fixed completely across the lock, prevents the
possibility of its being reached through the key-hole; and the first
tumblers T are quite detached at the time, thereby making it impossible
to ascertain the position of the parts in the inner chamber behind the
wall I I. K is the drill-pin, on which the key fits; and C is a
revolving ring or curtain, which turns round with the key, and prevents
the possibility of inspecting the interior of the lock through the
key-hole. Should, however, this ring be turned to bring the opening
upwards, a detector-plate D, fig. 42, is immediately carried over the
key-hole by the motion of a pin _p_¹ upon the auxiliary tumbler T⁴,
which is lifted by the revolution of the ring C, thereby effectually
closing the key-hole. As an additional protection, the bolt is held from
being unlocked by the stud or stump S bearing against the
detector-plate; and, moreover, the lever _l l_ holds the bolt, when
locked, until it is released by the tail of the detector-plate pressing
the pin _p_¹; _l_¹ is a lever which holds the bolt on the upper side,
when locked, until it is lifted by the tumblers acting on the pin _p_¹;
X are separating-plates between the intermediate tumblers T³; _u u_¹ are
the studs for preserving the parallel motion of the different tumblers.

[Illustration: fig. 42. The detector plate of the Parautoptic lock.]

Fig. 43 represents the key in two different forms, or with the bits
differently arranged. Either form will lock the lock, but the other will
not then unlock it. The end of the key is represented in fig. 44,
shewing the screw which fixes the bits in their places. The bits for a
six-bitted key are shewn separately in fig. 45.

[Illustration: fig. 43. Key of the Parautoptic lock.]

[Illustration: fig. 44. End view of the key.]

[Illustration: fig. 45. Separate bits of the key.]

In 1847 the parautoptic lock was exhibited at Vienna before the National
Mechanics’ Institute of Lower Austria; and towards the close of the year
Mr. Belmont, consul-general of Austria at New York, placed in the hands
of Messrs. Day and Newell a letter, a diploma, and a gold medal,
forwarded by the Institute. The letter was from the president of the
Institute to Mr. Newell, and was couched in the following terms:

“The Institute of Lower Austria, at its last monthly session, has passed
the unanimous resolution to award to you its gold medal, as an
acknowledgment of the uncommon superiority of the combination-lock of
your invention; and this resolution was ratified in its general
convention held on the 10th instant.

“Whilst I, as president of this Institute, rejoice in seeing the
services which by this invention you have rendered to the locksmith’s
art thus appreciated and recognised, I transmit to you, enclosed, the
said medal, together with the documents relating to it; at the same
time availing myself of this opportunity to assure you of my esteem.

  “COLLOREDO MANNSFELD.

  “Vienna, May 31st, 1847.”

The diploma and the medal were similar to other honorary distinctions of
the same class, and need not be described here; but the report of the
special committee may be given, as it expresses the opinions of the
Viennese machinists on the relative principles by which safety is sought
to be obtained in different kinds of locks.

REPORT

  _Of a Special Committee on the new Parautoptic Permutation Lock of the
  American Newell, made known to the Lower Austrian Institute by the
  Councillor, Professor Reuter, and on the motions relating to it made
  by the same and accepted by the Institute. Presented at the monthly
  meeting, April 6th, 1847, by Mr. Paul Sprenger, Aulic Councillor on
  Public Works, &c. &c._

  GENTLEMEN:--At our last monthly meeting, Mr. Reuter, Aulic Councillor
  and Secretary of the Institute, directed your attention to a newly
  invented lock of Mr. Newell, of North America, which was represented
  as excelling all other changeable combination-locks hitherto known,
  and as being without a rival.

  The Special Committee which was intrusted with the examination of this
  lock, and of the motions made by the said Secretary, and accepted by
  the Institute, has conferred on me the honour of making you acquainted
  with the results of its investigations.

  The attention of your committee was chiefly occupied with the three
  questions proposed by the said Aulic Councillor in relation to the
  lock in question:

  First: Whether the idea of Mr. Newell was of any practical value for
  already existing and still-to-be-invented combination-locks;

  Secondly: Whether the idea was of sufficient importance to be
  published and minutely described in the transactions of the said
  Institute; and

  Thirdly: Whether the merits of the inventor were of sufficient
  importance to entitle him to a distinction from the said Institute.

  The deliberations on the first question, viz. the newness of the idea,
  and of its practical value, would of necessity enlist the particular
  attention of your committee, especially since by far the greater
  number of its members are by their avocation called upon to be
  interested in the execution of all kinds of locks.

  It is therefore the unanimous opinion of your committee, that the
  idea of the American Parautoptic Combination-Lock is entirely new and
  without example.

  The combination-locks with keys have, with few exceptions, such an
  arrangement that a determinate number of movable parts (the so-called
  combination-parts) must by the turning of the key be raised or lifted
  into a certain position, if it is desired to project the bolt, or,
  what is the same thing, to lock it out; consequently these parts, or,
  as they are technically termed, tumblers, could not be transposed or
  changed, from the circumstance that the key-bit was one solid piece,
  with various steps or notches adapted to the several tumblers, and one
  impression from it destroyed the security of the lock.

  In order, however, to add more security to such a combination-lock,
  and to make the key, in case it should be lost, or any counterfeit
  made from a wax impression, useless for an unlawful opening of the
  lock, another step was taken: the key-bit was made to consist of
  several bits or movable parts, in such a manner that the owner of the
  lock was enabled to change the bits, and to form, _as it were_, new
  keys different from the former. But since the bolt of the lock can
  only be projected whilst the combination parts or tumblers are in a
  certain position, which position depends upon the order of the bits in
  the key, it is evident that the owner, when changing the key, must at
  the same time make a corresponding change in the position of the
  tumblers in the lock itself, before the lock can be of any use for the
  newly changed shape of the key, which rendered it troublesome, and
  impracticable for the purpose designed, from the fact that no positive
  change could be made in the lock, without taking it from the door, and
  then taking the tumblers out of the case, to change them in a suitable
  form for the key.

  This principle of changing the lock is rarely adhered to, as few men
  understand the machinery of a lock sufficiently to undertake the task;
  and this circumstance rendered the lock quite as insecure as the
  former one described.

  Another step toward the perfection of combination-locks consisted in
  this, that the key remains unaltered whilst the combination parts of
  the lock can, before it is locked, be brought into different positions
  by means of movable plates on the frame of the lock. These plates were
  arranged by hand to certain figures, and depended on the memory for
  adjustment at each time the bolt was to be locked out or in, the key
  operating only on the bolt, to move it back and forth when the plates
  were set in proper positions for the purpose; and should the owner
  forget the arrangement of the plates, after projecting the bolt, his
  key is of no use to him, and he must resort to the skill of the
  locksmith to gain access.

  The same case may occur in the far less perfect ring-lock of Reynier,
  which is operated without keys, and is opened by means of the rings
  being turned in a particular position; on these rings are usually
  stamped letters, which, by introducing some word readily suggested to
  the memory, thus point out the relative position of the rings.

  But although in case of these ring-locks the owner is enabled to
  produce a change in the rings in such a manner that the opening of
  the lock can, as it were, only become possible by rightly arranging
  the altered position of the letters, still this lock of Reynier’s does
  not possess that safety and perfection which could have insured it
  universal application.

  M. Crivelli, formerly professor at Milan, has given a minute
  description of the imperfection of ring-locks generally, in the annals
  of the Imperial Royal Polytechnic Institute.

  It is the unanimous conviction of your committee that the American
  Lock of Newell surpasses, in the ingenuity displayed in its
  construction, all other locks heretofore known, and more especially in
  this, that the owner can, with the greatest facility, change at
  pleasure the interior arrangement of his lock to a new and more
  complex one, at every moment of his life, simply by altering the
  arrangement of the bits in the key, and this is accomplished without
  removing the lock or any part of it from its position on the door.

  Its operation is as follows:--At the closing or locking of the lock,
  whilst the bolt is projecting, the movable combination parts assume
  precisely the position prescribed to them by the key, according to the
  particular arrangement of its bits at the time the key is turned.

  The combination parts do not consist in one set of tumblers only, such
  as are found in all other locks, but there are three distinct sets or
  component parts fitting into each other. When the bolt is projected,
  it dissolves the mutual connexion of the constituent pieces, and
  carries along with it such as are designedly attached to it, and which
  assume the particular positions given them by the key in its
  revolution. These parts are rendered permanent in their given form by
  means of a lever adapted for the purpose, while the parts not united
  with the bolt are pressed down by their springs to their original
  places.

  If now the bolt is to be returned again, _i. e._ if the lock is to be
  unlocked, then the constituent pieces or tumblers which are in the
  original state must, by means of the key, be again raised into that
  position in which they were when the lock was closed, as otherwise the
  constituent parts attached to the bolt would not lock in with the
  former, and the bolt could not be returned. Nothing, therefore, but
  the precise key which had locked the lock can effect the object.

  This idea in itself, considered by your committee, is as ingenious as
  it is new, and is accompanied by a perfection in its execution which
  reflects the highest honour on Mr. Newell, the inventor and
  manufacturer of the lock.

  The lock is built strong and solid, and the several parts are
  admirably adapted to the functions which they are designed to perform.
  The walls of steel or iron which separate the security parts from the
  tumblers, and the cylinder which revolves with the key, present
  formidable barriers to all descriptions of pick-locks, and render the
  lock a most positive and reliable security. The tumblers consist of
  rolled very smooth steel plates, in which the fire-crust has not been
  filed away, partly in order that the lock might not need oiling, as
  all these parts are very smooth, and partly that the combination
  pieces might not easily rust, a thing to which the adhering fire-crust
  is not favourable. The springs, which by the turning of the key must
  be raised together with the tumblers, are attached to levers, and
  press upon the latter at their centre of gravity, in consequence of
  which all crowding towards either side is prevented, and the key can
  be turned with facility, in spite of the many combination parts which
  it has to raise; and the springs themselves are by their positions so
  little called into action, that their strength can never be impaired
  by use.

  The lock has also another very complete arrangement in the
  detector-tumbler, which is attached to the cap or covering of the
  lock. This tumbler, on turning the key either way, closes the
  key-hole, and not only prevents the use of false instruments in the
  lock, but detects all attempts at mutilating its interior parts.

  This lock is especially useful for locking bank-vaults, magazines,
  counting-houses, and iron-safes, in which valuable effects, money, or
  goods are to be deposited for safe keeping. When it is considered that
  the bits of the key belonging to this lock can be transferred into
  every possible form within its limits, and since the construction of
  the lock admits of every combination of the slides resulting from the
  changes of the key, therefore the lock in question is, in every
  respect, deserving of the appellation given to it by the Secretary of
  the Institute, namely, the Universal Combination Lock; and justly so,
  when we consider that the ten bits attached to the key admit of three
  millions of permutations, and upward; consequently forming that number
  of different kinds of keys and locks.

  If we consider further, that we need not be limited to the given bit,
  but that others can be applied, differing in their dimensions from the
  former; and again, if we consider that from every system arising from
  a difference in their relative dimensions, a large number of new keys
  differing from each other will result, and that this can be effected
  in a space scarcely occupying a square inch,--then we cannot refrain
  from confessing that the human mind, within this small space, has
  shewn itself to be infinitely great.

  After this preliminary and general exposition, your committee can
  answer the three questions propounded to them the more briefly, as the
  locks heretofore known have all been noticed.

  To question first.--On the practical value of the invention of Mr.
  Newell, your committee were unanimous and positive that the principle
  on which it is based should be preserved.

  To question second.--For this reason the committee deemed it desirable
  that a drawing and description of the American lock in question should
  be published in the Transactions of the Institute of Lower Austria.

  To question third.--With regard to the claims of the inventor, Mr.
  Newell, to an honorary distinction from the Institute of Lower
  Austria, the committee recommend that he be presented with a Diploma
  of honourable mention and a Gold Medal.

  The members of your committee, consisting mostly of fellow-tradesmen
  of Mr. Newell, experience great satisfaction in the fact that it has
  fallen to their lot to vote to their colleague on the other side of
  the ocean an acknowledgment of his successful ingenuity, and they
  close the Report with the request that the Institute will transmit to
  Mr. Newell of New York, in North America, the Diploma and Gold Medal,
  together with a copy of this Report, according to the motion of the
  Aulic Councillor and Professor Reuter.

  [An exact copy of the original Report as preserved in the archives of
  the National Mechanics’ Institute of Lower Austria.]

  DR. SCHWARTZ,

  _Assistant Secretary of the Institute_.

There are other circumstances connected with the American bank-lock, in
relation to events both in the United States and in England, to which
attention will be directed in a subsequent chapter.

The English patent for Messrs. Day and Newell’s lock, dated April 15,
1851, runs as follows: “The object of the present improvements is the
constructing of locks in such manner that the interior arrangements, or
the combination of the internal movable parts, may be changed at
pleasure according to the form given to, or change made in, the key,
without the necessity of arranging the movable parts of the lock by
hand, or removing the lock or any part thereof from the door. In locks
constructed on this plan the key may be altered at pleasure; and the act
of locking, or throwing out the bolt of the lock, produces the
particular arrangement of the internal parts which corresponds to that
of the key for the time being. While the same is locked, this form is
retained until the lock is unlocked or the bolt withdrawn, upon which
the internal movable parts return to their original position with
reference to each other; but these parts cannot be made to assume or be
brought back to their original position, except by a key of the precise
form and dimensions as the key by which they were made to assume such
arrangement in the act of locking. The key is changeable at pleasure,
and the lock receives a special form in the act of locking according to
the key employed, and retains that form until in the act of unlocking by
the same key it resumes its original or unlocked state. The lock is
again changeable at pleasure, simply by altering the arrangement of the
movable bits of the key; and the key may be changed to any one of the
forms within the number of permutations of which the parts are
susceptible.”

The “claims” put forth under this patent are the following:--

“1. The constructing, by means of a first and secondary series of slides
or tumblers, of a changeable lock, in which the particular form or
arrangement of parts of the lock, imparted by the key to the first and
secondary series of slides or tumblers, is retained by a cramp-plate.

“2. The constructing, by means of a first and secondary series of slides
or tumblers, of a changeable lock, in which the peculiar form or
arrangement of parts of the lock, imparted by the key, is retained by
means of a tooth or teeth, and notches on the secondary series of slides
or tumblers.

“3. The application to locks of a third or intermediate series of slides
or tumblers.

“4. The application of a dog with a pin over-lapping the slide or
tumblers, for the purpose of holding-in the bolt when the lock is locked
or unlocked.

“5. The application of a dog operated on by the cap or detector-tumbler
for holding the bolt.

“6. The application of a dog for the purpose of holding the internal
slide or tumbler.

“7. The application to locks of curtains or rings, turning and working
eccentrically to the motion of the key, for preventing access to the
internal parts of the lock.

“8. The application to locks of a safety-plug or yielding-plate, at the
back of the chamber formed by such eccentric revolving curtain or ring.

“9. The application to locks of a strong metallic wall or plate, for the
purpose of separating the safety and other parts of the lock from each
other, and preventing access to such parts by means of the key-hole.

“10. The application to locks of a cap or detective tumbler, for the
purpose of closing the key-hole as the key is turned.

“11. The constructing a key by a combination of bits or movable pieces,
with tongues fitted into a groove and held by a screw.

“12. The constructing a key having a groove in its shank to receive the
detector tumbler.”

[Illustration: fig. 46. Movable stump.]

When the American locks became known in England, Mr. Hobbs undertook the
superintendence of their manufacture, and their introduction into the
commercial world. Such a lock as that just described must necessarily be
a complex piece of mechanism; it is intended for use in the doors of
receptacles containing property of great value; and the aim has been to
baffle all the methods at present known of picking locks, by a
combination of mechanism necessarily elaborate. Such a lock must of
necessity be costly; but in order to supply the demand for a small lock
at moderate price, Mr. Hobbs has introduced what he calls a _protector
lock_. This is a modification of the ordinary six-tumbler lock. It bears
an affinity to the lock of Messrs. Day and Newell, inasmuch as it is an
attempt to introduce the same principle of security against picking,
while avoiding the complexity of the changeable lock. The distinction
which Mr. Hobbs has made between secure and insecure locks will be
understood from the following proposition, viz. “that whenever the parts
of a lock which come in contact with the key are so affected by any
pressure applied to the bolt, or to that portion of the lock by which
the bolt is withdrawn, as to indicate the points of resistance to the
withdrawal of the bolt, such a lock can be picked.” Fig. 47 exhibits the
internal mechanism of this new patent lock. It contains the usual
contrivances of tumblers and springs, with a key cut into steps to suit
the different heights to which the tumblers must be raised. The key is
shewn separately in fig. 48. But there is a small additional piece of
mechanism, in which the _tumbler stump_ shewn at _s_ in figs. 46 and 47
is attached; which piece is intended to work under or behind the bolt of
the lock. In fig. 47, _b_ is the bolt; _t t_ is the front or foremost of
the range of six tumblers, each of which has the usual slot and notches.
In other tumbler-locks the stump or stud which moves along these slots
is riveted to the bolt, in such manner that, if any pressure be applied
in an attempt to withdraw the bolt, the stump becomes pressed against
the edges of the tumblers, and bites or binds against them. How far
their biting facilitates the picking of a lock will be shewn further on;
but it will suffice here to say, that the movable action given to the
stump in the Hobbs lock transfers the pressure to another quarter. The
stump _s_ is riveted to a peculiarly-shaped piece of metal _h h_ (fig.
46), the hole in the centre of which fits upon a centre or pin in a
recess formed at the back of the bolt; the piece moves easily on its
centre, but is prevented from so doing spontaneously by a small binding
spring. The mode in which this small movable piece takes part in the
action of the lock is as follows: when the proper key is applied in the
usual way, the tumblers are all raised to the proper heights for
allowing the stump to pass horizontally through the gating; but should
there be an attempt made, either by a false key or by any other
instrument, to withdraw the bolt before the tumblers are properly
raised, the stump becomes an obstacle. Meeting with an obstruction to
its passage, the stump turns the piece to which it is attached on its
centre, and moves the arm of the piece _p_ so that it shall come into
contact with a stud riveted into the case of the lock; and in this
position there is a firm resistance against the withdrawal of the bolt.
The tumblers are at the same moment released from the pressure of the
stump. There is a dog or lever _d_, which catches into the top of the
bolt, and thereby serves as an additional security against its being
forced back. At _k_ is the drill-pin on which the pipe of the key works;
and _r_ is a metal piece on which the tumblers rest when the key is not
operating upon them.

[Illustration: fig. 47. Hobbs’s Protector Lock.]

[Illustration: fig. 48. The key.]

Another lock, patented by Mr. Hobbs in 1852, has for its object the
absolute closing of the key-hole during the process of locking. The key
does not work or turn on its own centre, but occupies a small cell or
chamber in a revolving cylinder, which is turned by a fixed handle. The
bit of the movable key is entirely separable from the shaft or stem,
into which it is screwed, and may be detached by turning round a small
milled headed thumb-screw. The key is placed in the key-hole in the
usual way, but it cannot turn; its circular movement round the stem as
an axis is prevented by the internal mechanism of the lock; it is left
in the key-hole, and the stem is detached from it by unscrewing. By
turning the handle, the key-bit, which is left in the chamber of the
cylinder, is brought into contact with the works of the lock, so as to
shoot and withdraw the bolt. This revolution may take place whether the
bit of the movable key occupy its little cell in the plate or not; only
with this difference--that if the bit be _not_ in the lock, the plate
revolves without acting upon any of the tumblers; but if the bit be in
its place, it raises the tumblers in the proper way for shooting or
withdrawing the bolt. It will be understood that there is only one
key-hole, namely, that through which the divisible key is inserted; the
other handle or fixed key working through a hole in the cover of the
lock only just large enough to receive it, and not being removable from
the lock. As soon as the plate turns round so far as to enable the
key-bit to act upon the tumblers, the key-hole becomes entirely closed
by the plate itself, so that the actual locking is effected at the very
time when all access to the interior through the key-hole is cut off.
When the bolt has been shot, the plate comes round to its original
position, it uncovers the key-hole, and exhibits the key-bit occupying
the little cell into which it had been dropped; the stem is then to be
screwed into the bit, and the latter withdrawn. It is one consequence of
this arrangement, that the key has to be screwed and unscrewed when
used; but through this arrangement the key-hole becomes a sealed book to
one who has not the right key. Nothing can be moved, provided the bit
and stem of the key be both left in; but by leaving in the lock the
former without the latter, the plate can rotate, the tumblers can be
lifted, and the bolt can be shot.




CHAPTER VIII.

THE LOCK CONTROVERSY: PREVIOUS TO THE DATE OF THE GREAT EXHIBITION.


It must be evident, even on a cursory glance at the past history of the
lock-manufacture, that the prime motive for the introduction of
novelties and improvements in construction is the desirability of
producing a lock which no one can open without the proper key. From the
earliest and simplest lock, down to the latest and most complex, this
object has been constantly held in view; and every clear proof or
evidence that this object has not been attained has led to the invention
of some new contrivance. It has been a succession of struggles--to
attain security--to shew that this security has not been attained--to
make a further and more ingenious attempt--to detect the weak point in
this renewed attempt--and so on. We need not repeat here, what was
stated in an early chapter, that benefit must ultimately result from a
candid discussion of this question. When M. Réaumur proposed to explain
how the locks of his day could be picked or opened without the true key,
his object was to shew to persons who were not locksmiths how far they
could depend upon the principle of security offered by locks. But before
proceeding on his inquiry, the illustrious naturalist asks, “Ne
craindra-t-on pas que nous ne donnions en même tems des leçons aux
voleurs?” And he replies, “Il n’y a pas grande apparence qu’ils viennent
les chercher ici, et qu’ils en aient besoin; ils sont plus grands
maîtres que nous dans l’art d’ouvrir les portes. Apprenons donc l’art
d’ouvrir les portes fermées, afin d’apprendre celui de les fermer d’une
manière qui ne laisse rien ou qui laisse peu à craindre.”[5]

  [5] “But is there not this danger, that at the same time we shall be
  giving lessons to the thieves? It is not very probable that they will
  seek instruction of us, or that they have any need of it; they are
  greater masters in the art of opening doors than we can pretend to be.
  Let us then learn the art of opening locked doors, in order that we
  may acquire that of securing them in such a way as to leave little or
  nothing to be feared on account of their security.”

Before treating of lock controversies and lock violability in England,
it will be desirable first to refer to America, where this subject
attracted much attention some years earlier than the Great
Exhibition--an Exhibition which will always be associated in a
remarkable manner with the history of locks.

Soon after the inventions by Dr. Andrews and Mr. Newell, in 1841
(described in a former chapter), the rivalry between the two locks ran
high; each lock being ‘unpickable,’ according to the estimate of its
inventor. Mr. Newell thought the best mode of shewing the superiority of
his own lock would be by picking that of his competitor; and after
several trials, he succeeded in bringing into practical application that
system of picking which we may designate the _mechanical_, as
contra-distinguished from the _arithmetical_. Mr. Newell not only picked
Dr. Andrews’ lock, but he wound up the enterprise by picking his own! He
was probably the first person who honestly confessed to having picked
his own unpickable lock. This discovery led Mr. Newell, as has been
noticed in a former page, to the invention of the triple-action or
parautoptic lock.

The mechanical principle, as applied to the picking of a tumbler lock,
is nearly the same whatever form of construction be made the medium of
experiment. When a pressure is applied to the bolt sufficient to unlock
it if the tumbler-obstructions were removed, the edges of the tumbler
bite or bind against the stump of the bolt, so as not to move up and
down with such facility as under ordinary circumstances. By carefully
trying with a small instrument each tumbler, and moving it until the
bite ceases, the gating of that particular tumbler may be brought to the
exact position for allowing the stump of the bolt to pass through it.
(See page 118.)

This violability is observable in the tumbler-locks under very varied
forms of construction. Mr. Newell, after he had picked his own lock,
devised a series of complicated wards, to add to the difficulty of
reaching the tumblers; but he could not thereby get rid of the
importance of this fact, that wherever a key can go, instruments of a
suitable size and form could follow: his wards did not render his lock
inviolable. His next contrivance was to notch the abutting parts of the
primary and secondary tumblers, or the face of the stump and the ends of
the tumblers; but this failed also. Mr. H. C. Jones, of Newark, N. J.,
added to all this a revolving pipe and curtain, to close as much of the
key-hole as possible. But so far were all these precautions from being
successful, that a lock provided with all these appendages, and affixed
to the door of the United States Treasury at Washington, was picked. The
makers of locks have, each one for himself, contended against such
difficulties as were known to them at the time of inventing their locks;
and, mortifying as failure may be, it would be cowardly to yield up the
enterprise whenever any new difficulty presented itself. Difficulties,
in locks as in other matters, are made to be conquered.

To shew how numerous are the sources of insecurity which have to be
guarded against, to meet the skill often brought to bear upon this
lock, we may adduce the reasons which led Mr. Newell to apply a curtain
to the key-hole of his lock. Supposing the interior arrangement of the
triple set of tumblers, and the metallic shielding wall, to be perfect,
still, _if the first set of tumblers can be seen through the key-hole_,
the following plan may be put in operation. The under-side of the
tumblers may be _smoked_, by inserting a flame through the key-hole; and
the key will then leave a distinct mark upon each tumbler the next time
it is used, shewing where it began to touch each tumbler in lifting it.
This may be seen by inserting a small mirror hinged into the lock
through the key-hole. There may even be an electric light used from a
small portable battery, to illumine the interior of the lock. By these
and other means the exact length of each bit of the key may be
determined; and from these data a false key may be made. It is to
prevent this inspection of the works, or any other examination of an
analogous kind, that the revolving curtain was applied; but, as stated
in the last paragraph, even this did not suffice: ingenuity devised a
mode of baffling the contrivance of curtains as well as that of the
wards and false notches in the tumblers.

When the parautoptic lock was completed, it was keenly criticised in
America, owing to the long discussions respecting the merits of previous
locks. In a matter of this kind, where a commercial motive would lead
bankers and companies to apply a very severe test to the security of
locks and similar fastenings to strong-rooms and receptacles, any
experiments made with their sanction became important. Mere letters or
certificates emanating from individuals, expressive of opinions
concerning a particular lock, would be out of place in a volume relating
to locks generally; but it is quite within the limits of the subject,
and has indeed become part of the history of locks, to notice
experiments and attempts of a more public character. We may therefore
introduce a few paragraphs of this description, relating to the career
of the American lock in America itself.

The principal bankers at Boston (U.S.) held a meeting to take into
consideration measures for testing the security of bank locks.
Consequent on this meeting, Messrs. Day and Newell deposited five
hundred dollars with the cashier of the State Bank at Boston, to be by
him paid to any one who could pick the parautoptic lock: the trial was
to be conducted under the auspices of the bank. One of the locks was
brought to the bank, and was minutely examined by two machinists on two
afternoons, after which it was secured to an iron chest, and locked by a
committee appointed by the bank. The key was to remain in the hands of
the committee during the trial; and it was to be used at their
discretion, in unlocking and locking the door, without the knowledge of
either of the other parties--provided that in so doing no alteration was
made in the combination-parts of the key. Ten days were allowed to the
operators for the examination and the trial; if they succeeded they were
to have five hundred dollars; but if they injured the lock they agreed
to forfeit two hundred, as a purchase price. At the end of the period
the lock remained unopened and uninjured; and the two deposited sums
were accordingly returned to the respective parties.

Messrs. Page and Bacon, of St. Louis, had a strong-room lock made by one
of the chief locksmiths of that city. To test its security, the
proprietors requested Mr. Hobbs to attempt to pick it; he did so, and
succeeded. Whereupon the proprietors, having purchased one of the
parautoptic locks, deemed it no more than fair play to subject this lock
to a similar ordeal, an additional zest being given by a reward of five
hundred dollars offered by Day and Newell to the successful picker. The
maker of the former lock accepted the challenge; he was allowed to
examine the new lock piecemeal, and was then allowed thirty days for his
operations in picking. He failed in the enterprise. Of course, in this,
as in all similar cases, the operator had not access to the true key.

It follows from the nature of this lock, as noticed in a former chapter,
that when the bolt has been shot, if the bits of the key be re-arranged
in any other form, the lock becomes to all intents and purposes a new
lock, so far as that key is concerned, and cannot be unlocked unless the
key revert to its original arrangement. To test this principle, a box
with a parautoptic lock was placed in the room of the American Institute
in 1845; it was locked; the bits of the key (12 in number) were then
re-arranged, and the key was placed in the hands of any one who chose to
try to open the lock--with the offer of a reward of five hundred dollars
in the event of the lock being opened. Here, instead of the operator
being called upon to devise new pick-lock implements, he had the actual
key placed in his hands, modified however in such a way that, though the
modifier could restore the original arrangement (provided he had kept
some kind of record), the operator had numerous chances against his
success. The lock remained unopened notwithstanding this challenge.

We shall have occasion to shew presently, that if the number of tumblers
(and consequently the number of bits in the key) be small--not exceeding
six, for instance--the possession of the _true_ key gives any one the
power of opening the lock, provided he has time and patience to go
through a few hundred changes of the bits of the key; for, as some one
arrangement must have been that by which the lock was locked, it must
again occur if the user takes care to make _all_ the arrangements in
turn, and tries the lock after each. Whether this constitutes picking a
lock, each lock-owner will decide for himself. All that it is at present
meant to state is, that _without_ access to the true key, the
parautoptic lock has not hitherto been opened; and that _with_ the true
but altered key the process of opening is possible, but is slow and
tedious.

In 1846 the American Institute appointed a committee to examine into the
merits of the parautoptic lock. On the 18th of September in that year
the Committee made their report, signed by Professor Renwick and Mr. T.
W. Harvey, as follows:--

“The Committee of the American Institute, to whom was referred the
examination of NEWELL’S PARAUTOPTIC BANK LOCK, report that they have
given the subject referred to them a careful and attentive examination,
and have received full and complete explanations from the inventor. They
have remarked in the lock a number of important advantages, and, in
particular, very great improvements upon the permutation-lock formerly
submitted by him to the American Institute. Thus, while it retains the
advantages of the permutation principle, combined with the property that
the act of locking sets the slides to the particular arrangement of the
bits in the skeleton key, the parts thus set are completely screened
from observation, from being reached by false instruments, or from being
injured by any violence not sufficient to break the lock to pieces.

“Having in the course of their inquiries examined the different existing
modes in which locks may be picked, forced, or opened by false keys, the
Committee have come to the conclusion that the parautoptic lock cannot
be opened by any of the methods now practised, unless by a person in
possession of the key by which it was locked, in the exact form of
combination in which it was used for the purpose, or in the almost
impossible case of the bits being adjusted to the skeleton key by
accident in that very form. As the chances of such accidental
combination range according to the number of movable bits, from several
thousands to several millions to one, the Committee do not conceive that
so small a chance of success would ever lead to an attempt to profit by
it.

“In conclusion, the Committee feel warranted in expressing the opinion,
that unless methods hitherto unknown or imagined should be contrived for
the specific object, the lock in question may be considered as affording
entire and absolute security.”

The latest form which Messrs. Day and Newell have given to their
challenge, after the experience of the last few years, is the following:

“First, a Committee of five gentlemen shall be appointed in the
following manner: viz. two by the parties proposing to operate, and two
by ourselves; and by the four thus appointed a fifth shall be selected.

“In the hands of this Committee shall be placed Two Thousand Dollars, as
a reward to the operator if successful in picking the lock by fair
means.

“We will place upon the inside of an iron door one of our best bank
locks. The operator shall then have the privilege of taking the lock
from the door, and have it in his possession for examination; it shall
then be returned to the Committee for our inspection, so that we may be
assured that it has not been mutilated or injured. The operator shall
then, in the presence of ourselves and the Committee, place the lock
upon the door in its original position; after which the Committee shall
place upon it their seals, so that it cannot be removed or altered
without their knowledge. The lock being thus secured to the door, we
shall then be allowed to lock it up ourselves, upon any change of which
it is susceptible.

“The time for operation to continue thirty days; and if at the end of
that time he shall consider that he has made any progress towards
picking the said lock, he shall have thirty days more in which to
continue operations.”

The Austrian report concerning the American lock was given in a former
page, to which we may here refer; and then direct attention to England,
and to the discussions which have lately been carried on respecting the
safety of locks.

It is of course natural that each inventor of a new lock should, while
describing the product of his ingenuity, point out what he conceives to
be the imperfections of locks which have preceded: use has sanctioned
the custom not only with regard to locks, but also in other important
matters. Hence there have been many “lock controversies” in England
during the last seventy years. We have seen how freely and justly the
late Mr. Bramah criticised all the locks that preceded his own; and he
was certainly not the man to shrink from criticism in his own case.
Twenty years ago the Bramah lock was itself made the subject of
criticism.

Mr. Ainger, in his lecture on the subject delivered at the Royal
Institution, London, and afterwards in his article “Lock” in the
_Encyclopædia Britannica_, thus narrates the circumstances which led to
the adoption of the false notches in the Bramah lock as a means of
security: “At length (after the original lock had acquired much
celebrity,) an advertisement appeared in the public papers, requesting
those who had lost keys of Bramah’s locks, not, as had hitherto been
done, to break open their doors or drawers, but to apply to the
advertiser, who would undertake to save this destructive process by
picking. And it appeared that an individual of great dexterity could
perform this operation almost with certainty. The effect of this
discovery on the demand for the locks may easily be imagined; but the
effect it had in stimulating ingenuity to provide a remedy is one of the
best illustrations of the proverb, that necessity is the mother of
invention. Within a few days or weeks, Mr. Russell, who was at that time
employed in Mr. Bramah’s establishment, devised an alteration which at
once, and without any expense, entirely overcame the difficulty, and
converted the lock into one of perfect security. This contrivance is the
most simple and extraordinary that ever effected so important an object;
but before we describe it, we will endeavour to explain what has been
called the _tentative_ process of lock-picking, and which had been so
successfully applied to Bramah’s locks.”

Mr. Ainger illustrates the subject by an engraving--not of an actual
lock, but of an hypothetical arrangement of bolts and notches; and he
then makes his reasoning apply to the actual process adopted by the
picker of the real lock. “A tendency to revolve was given with some
force to the barrel; then, by means of a pair of small forceps, the
tumblers (sliders) were tried, and it was ascertained which one was most
detained by the pressure against the locking-plate. That which offered
most resistance was gradually depressed till its notch was felt to hang
itself upon the locking-plate; and so on till the whole were depressed
in succession, exactly as they would have been depressed simultaneously
by the key.” Mr. Ainger then describes the contrivance which, in his
judgment, seemed to render any further attempts to pick the Bramah lock
hopeless. This consisted in cutting false notches in the sliders; so as
to render it impossible for the picker to tell when he has brought a
notch to the plane of the locking-plate, whether it is a true notch, or
one of shallower depth, unfitted to admit the movement of the plate.

This is a very interesting statement, for it shews that the mechanical
or tentative method of opening was known in England long ago, although
very little attention has been since paid to it. In a complex Bramah
lock, and in locks on the combination principle, the difficulty of
picking is almost insuperable, so long as what may be termed the
arithmetical method is adopted. It is perfectly true, as has been so
often stated, that the varied combinations in the arrangement of the
slides amount to millions and even billions, when the slides are in any
degree numerous; and if a person attempt to pick the lock by ringing the
changes on all these combinations, it would very likely require the
lives of a dozen Methuselahs to bring the enterprise to an end. But by
the mechanical method, sketched so clearly by Mr. Ainger, the exploit
puts on a different aspect. The experimenter passes through the keyhole
an instrument so arranged as to give a _tendency_ in the bolt to
withdraw in the wished-for direction; and a pressure produced in the
slides by this tendency gives information concerning the state of the
slides; and then comes the tentative process on the slides themselves.
Mr. Ainger was quite right in describing the false notches as an
admirable addition to the safety of the Bramah lock; but he was not
correct in stating that these notches rendered any further attempts on
the lock hopeless. The false notches are not so deep as the true; they
will permit the barrel to turn partially but not wholly round. But even
supposing that the false notch had been hit upon in nearly every slide
instead of the true, and that the barrel had been partially turned to
the extent which these notches permitted, there would then be a binding
action at the false notches different from that in the true, and this
would guide the operator in his search for the true notches. It would
not add a new principle different from the one before in action, but it
would add to the time during which the search would have to be carried
on.

We make these remarks in connection with Mr. Ainger’s article, which was
probably written twenty years ago. We now come to the year 1850.

At the meeting of the Institution of Civil Engineers, when Mr. Chubb’s
paper was read, many challenges and counter-challenges were made, as to
the possibility of picking certain locks. Mr. Chubb described, among
others, a lock on the patent of Mr. Davies, which, ingenious though it
be, he considers not safe. Captain D. O’Brien differed from Mr. Chubb in
this matter; he had had occasion to open from ten to twenty of Davies’s
cabinet-locks daily, during a period of two years, and he never once
observed the locks to be out of order; in fact, they always appeared to
afford great security. Mr. Chubb thereupon rejoined, that he was
prepared to produce a workman who would pick any number of Davies’
cabinet-locks, of different combinations, which he had never seen
before, taking only half an hour for each lock.

As another instance, Captain O’Brien stated that, in his capacity as
Inspector of Government Prisons, his attention had been much directed to
the subject of secure locks; and he produced, among others, specimens of
those in use at the Pentonville Prison; though not of first-rate
workmanship, he characterised them as being safe, strong, and cheap.
They were on Thomas’s principle. The locks had been in use eight years,
during which period not one had required to be replaced; and any
trifling derangements had been made good whilst the prisoners were at
exercise. Mr. Chubb, after making his offer concerning Davies’s lock,
stated that “he was willing to make the same offer with respect to the
locks from the Pentonville Prison; and he might state that, in point of
security, he considered them absolutely worthless;” in proof of which he
exhibited one of them, and a common burglar’s tool, by which the lock
could be opened with the greatest ease.

In respect to Bramah’s lock, there was no particular challenge
associated with the proceedings of the evening; but incidental
observations were made as to the degree of security pertaining to it.
Mr. Farey, after passing a high eulogium on the ingenuity of the
principle and the beauty of the workmanship, considered it nevertheless
objectionable that the sliders should be so completely exposed to view.
He then proceeded to make the following observations: “It had been
suggested, that a universal false key for Bramah’s locks might be made,
with the bottoms of its several notches formed by as many small steel
sliders, extending beyond the handle of the key, so as to receive
pressure from the fingers, for moving each one of the sliders within the
lock, with a sliding motion in its own groove, independently of the
other. During such sliding motion, a gentle force could be exerted,
tending to turn the barrel round. Under such circumstances, supposing
that the motion of the barrel was prevented by any one slider only; that
one, having to resist all the turning force, would be felt to slide more
stiffly endways in its groove, and therefore it could be felt when its
unlocking notch arrived opposite the steel plate, and left some other
slider to begin to resist the turning force. Such a circumstance
(continues Mr. Farey) presumes a palpable inaccuracy in the radiating
correspondence between the notches in the steel plate and the grooves
for the sliders in the barrel, which could not happen with Bramah’s
workmanship.”[6] He further remarked: “Unfortunately, if a Bramah’s key
fell into dishonest hands, even for a short time, an impression could be
easily taken, and a false key as easily made. A turkey-quill, notched
into the form of a key, had sufficed to open a Bramah’s lock; and an
efficient false key could be formed out of a pocket pencil-case. Such
facility of fabrication was an invitation to dishonesty; and as an
abortive attempt left no trace, the impunity was an encouragement to
repeat the attempt until success is attained.”

  [6] See also Mr. Owen’s suggestion, p. 59, _ante_.

With respect to Chubb’s locks, a discussion arose out of a statement
made by Mr. Hodge. Mr. Chubb had himself stated it to be a general
opinion that a skilful workman, furnished with impressions taken from
the true key, in wax or soap, could make a false key to open any lock;
and he considered that, in common locks, with the most elaborate wards,
but with only one tumbler, as also in Bramah’s locks, there was much
truth in the notion. In respect to his own lock, however, with six
double-acting tumblers, “a false key made ever so carefully from
impressions would not be likely to open the lock, for want of exactitude
in the lengths of the several steps; and if the key could not be made
exact from the impressions, there would be no chance of rectifying it by
trial in the lock, on account of the total uncertainty as to which part
required alteration.” Mr. Hodge stated that, in America, he had
repeatedly seen impressions taken of locks having twelve or fourteen
tumblers, in consequence of the bellies of the tumblers, when at rest,
coinciding with the form of the key (see page 63). He also suggested a
method of taking an impression of the bellies of the tumblers; but Mr.
Chubb, Mr. Farey, Mr. Stephenson, and Mr. Whitworth, all expressed a
disbelief that a Chubb’s lock could be opened by the means indicated by
Mr. Hodge. Mr. Hodge admitted that he was not aware of any lock actually
made by Messrs. Chubb having been picked in America; but that the locks
to which he had adverted were such exact imitations, that he had no
doubt of the Chubb lock yielding to similar treatment. He further stated
that there were persons in New York who would undertake to pick a real
Chubb lock.




CHAPTER IX.

THE LOCK CONTROVERSY: DURING AND SINCE THE TIME OF THE GREAT EXHIBITION.


We next come to the remarkable year 1851, which produced so many
unexpected results in connection with the industrial display in Hyde
Park, and conferred a lasting benefit on the useful arts and
manufactures of the United Kingdom, by bringing their products into
contrast and competition with those of other nations. It was to be
expected that such a trial as this would afford evidences of national
failure as well as of success; but probably no one suspected before the
trial, that English locks, so celebrated over the greater part of the
world for skilful mechanical design, beauty of workmanship, and perfect
inviolability, would readily yield to a well-arranged system of
lock-picking. Such, however, was the case; and we are bound to admit
that Mr. Hobbs, the author of this system, is a mechanician of great
skill, and with a profound knowledge of the art of the locksmith.

The first step in the celebrated _lock controversy_ of 1851 was taken by
Mr. Hobbs himself, who declared to a party of scientific men in the
Crystal Palace, that all the locks made in this country up to that date
admitted of being very easily picked; and in order to explain to these
gentlemen the principle upon which this was to be done, Mr. Hobbs picked
one of Chubb’s patent detector-locks in their presence in a few minutes.

The fairness of this experiment having been called in question by
certain persons who were not present at the time when it was made, Mr.
Hobbs, on July 21st, 1851, wrote a letter from the American department
of the Great Exhibition, to Messrs. Chubb, simply announcing that an
attempt would be made, on the next following day, to pick a lock
manufactured by them, and which was at that time on the door of a
strong room in a house named by Mr. Hobbs. Messrs. Chubb were invited to
be present at the operation; but no member of the firm attended. What
occurred on the day specified may best be given in the words of a letter
written by those who witnessed the operation.

  “London, July 22, 1851.

“We the undersigned hereby certify, that we attended, with the
permission of Mr. Bell, of No. 34 Great George-street, Westminster, an
invitation sent to us by A. C. Hobbs, of the City of New York, to
witness an attempt to open a lock throwing three bolts and having six
tumblers, affixed to the iron door of a strong-room or vault, built for
the depository of valuable papers, and formerly occupied by the agents
of the South-Eastern Railway; that we severally witnessed the operation,
which Mr. Hobbs commenced at 35 minutes past 11 o’clock A.M., and opened
the lock within 25 minutes. Mr. Hobbs having been requested to lock it
again with his instruments, accomplished it in the short space of 7
minutes, without the slightest injury to the lock or door. We minutely
examined the lock and door (having previously had the assurance of Mr.
Bell that the keys had never been accessible to Mr. Hobbs, he having had
permission to examine the key-hole only). We found a plate at the back
of the door with the following inscription: ‘Chubb’s New Patent (No.
261,461), St. Paul’s Churchyard, London, Maker to Her Majesty.’”

This letter was signed with the names and addresses of the following
gentlemen:--

  Mr. Handley.                Mr. T. Shanks.
   „  William Marshall.       Colonel W. Clifton.
   „  W. Armstead.            Mr. Elijah Galloway.
   „  G. R. Porter.[7]         „  Paul R. Hodge.
   „  F. W. Wenham.            „  Charles H. Peabody.
   „  A. Shanks.

  [7] Late Secretary to the Board of Trade.

Several of these names are well and publicly known in England and the
United States.

This event gave rise to much newspaper controversy; and attempts were
made to shew that, as this was not a _test_ lock, prepared expressly for
challenge, the picking proved nothing as regards the finest of the
manufacturers’ locks. Two circumstances, however, have to be
noticed--that the lock was of sufficient commercial importance to be
placed on a door enclosing valuable papers, and that the makers had an
opportunity to attend and witness, and comment on the trial, if they so
chose. We may here remark, that one of the ingenious contrivances of the
Chubb lock, the _detector_, excited some doubt no less than fifteen
years ago, as will be seen from the following. The writer of the article
“Lock” in Hebert’s _Engineers’ and Mechanics’ Encyclopædia_, while
speaking with much commendation of Chubb’s locks, points out a curious
feature, which seems to him to render somewhat doubtful the surety of
the _detector_ apparatus. “In Barron’s and Bramah’s locks,” he observes,
“the picker has no means of knowing whether the tumblers are lifted too
high or not; but in Chubb’s he has only to put the detector _hors de
combat_ in the first instance, by a correct thrust from the outside of
the door (which might be accurately measured), so as to _fix_ it fast in
its place; the detector then becomes a stopper to the undue ascent of
the tumblers, and the extent of their range is thereby correctly
ascertained. Thus, it appears to us, the _detector_ might be converted
into a _director_ of the means for opening the lock.”

Much will depend on the view which is taken of the circumstance just
noted. The object of the detector is, not to prevent the lock from being
picked, but to shew that an attempt has been made to pick it; or, at
least, to attain a given purpose by an indirect instead of a direct
method. But if there be really any truth in the surmise, that the
detector actually guides a skilful hand in determining how high the
tumblers should be raised, the supposed advantage will be purchased at
rather a dear rate. As we are here, however, speaking of facts and not
of mere opinions, it is proper to say, that the lock opened by Mr.
Hobbs had the detector apparatus, but that it was not disturbed by him
in picking the lock.

But instead of reiterating opinions, we will state the method by which
most of the tumbler-locks made in England, up to the date of the Great
Exhibition, can be opened or picked.

Bearing in mind the principle on which the picking of locks is said to
depend, namely, that “whenever the parts of a lock which come in contact
with the key are affected by any pressure applied to the bolt, or to
that portion of the lock by which the bolt is withdrawn, in such a
manner as to indicate the points of resistance to the withdrawal of the
bolt, such a lock can be picked,” the first step is to produce the
requisite pressure.

[Illustration: fig. 49.]

If the end of the bolt were exposed, this pressure might be applied by
some force tending to shoot back the bolt; but as the bolt, whenever it
is shot, is buried in the jamb of the door, or otherwise concealed from
view, the pressure can in general only be applied through the key-hole.
In order, therefore, to apply this pressure, the operator provides
himself with an instrument capable of reaching the talon of the bolt,
which in the case of the Chubb lock was a pipe-key of the form shewn at
_a b_, fig. 49, furnished at the pipe-end with that portion of the bit
of the key _b c_ which moves the bolt (see fig. 32, page 57, where the
step which acts on the bolt is called the terminal step). The other end
of the pipe-key is made square, as at _a_, for the purpose of receiving
the square eye _e_ of the lever _e f_, fig. 50, to the further end of
which _f_ a weight _w_ is attached by means of a string _s_. Now it is
evident that if this pipe be introduced into the lock as far as it will
go, and be turned round as in the act of unlocking, and the lever and
weight be attached to the end _a_, the bit _b c_ of the pipe-key will
maintain a permanent pressure on the bolt, which, if the weight be
sufficient, will throw back the bolt as soon as the tumblers are raised
to the proper height to allow the stump to pass.

[Illustration: fig. 50.]

The next step in the operation is to raise the tumblers to the proper
height. For this purpose a second pipe _m n_ is made to slide upon the
first with an easy motion, and by means of the cross handle _h h_ can be
turned round or slid backwards and forwards on the tube _a b_. This tube
_m n_ is also furnished with a single projecting bit or step _n o_,
corresponding with one of the six steps of the key, fig. 32, and made of
the proper length for entering the key-hole.

Now for the operation of opening a tumbler-lock with this simple
apparatus. Referring to fig. 31, page 56, it will be evident that if the
pipe _a b_, fig. 49, be passed over the pin of the lock and turned round
towards the left, and the weight be attached, there will be a tendency
in the bolt to shoot back, which tendency will bring the stump _s_, fig.
31, up against the inner angle or shoulder of one or other of the
tumblers, whichever happens to project, however slightly; or, as Mr.
Hobbs expresses it, “one or more of the tumblers will bind.” By moving
forward the pipe _m n_ and turning round the bit _n o_ in the lock, it
is easy to ascertain, by delicate touch, which of the tumblers it is
that binds. It may be found that all are free to move except one or two
against which the stump is pressing with the force of the weight _w_,
fig. 50. The bit _n o_ is therefore brought gently under the bellies of
the tumblers which bind, and they are moved slightly upwards until they
cease to bind. As soon as they are set free another tumbler will bind;
that is, the bolt will move through a small space, so as to bring the
stump into contact with that particular tumbler which now projects; this
in its turn is relieved, another tumbler binds and is relieved, and so
on until the tumblers are, one by one, raised to the proper height for
the stump to pass. When the last binding tumbler is raised to the proper
height, the weight _w_ being no longer resisted, shoots the bolt back,
and the work is done.

Now it must be evident that in this operation the detector apparatus
need not come into operation. But if, as has been proposed, a
detector-spring be added to each tumbler, it may be converted into a
friend or a foe according to the use that is made of it. If the tumblers
are lifted _too high_, they will be detained or detected in that
position, and the operator will have to release them by turning the bit
round in the opposite direction before he can begin his work again. The
same force, however, which detains the tumblers when they are lifted too
high will obviously detain them when they are lifted only just high
enough, and thus the detector-springs would really be of great
assistance to the operator in picking such a tumbler-lock.

The apparatus which we have described for picking the tumbler-lock must
be varied to suit the form of key employed in opening the lock; but it
is not difficult, in the case of most locks, to ascertain this form
through the key-hole, without examining the key itself.

It is but fair to state in this place, that since the above method of
picking tumbler-locks was made known,[8] Mr. Chubb has added a series
of teeth and notches to the stump and tumblers; the effect of which
would evidently prevent the application of the above method of picking,
because any permanent pressure applied to the bolt would send a tooth of
the stump into a notch of the tumbler, and prevent all further motion.
But recurring to the principle, that whenever the parts of a lock which
come in contact with the key indicate the points of resistance when any
pressure (_whether permanent or temporary_) is applied in attempting to
withdraw the bolt, that lock can be picked, it follows, if this
principle be admitted, that although the notches prevent the application
of the form of instrument described, yet there is sufficient indication
afforded by the pressure to enable a skilful operator, with proper
instruments, to form a false key, as was done in the case of the lock
referred to at page 104. We now proceed to the second stage in the lock
controversy of 1851.

  [8] We believe the method was first made publicly known at a special
  general meeting of the members of the Institution of Mechanical
  Engineers, held at the rooms of the Society of Arts, London, on the
  30th June, 1851, when a paper was read by Mr. Paul R. Hodge “On the
  progress of improvements in locks in the United States of America.” A
  report of this paper, together with the discussion thereon, was
  published by Waterlow and Sons, London Wall, 1851. Plate 34 (figs. 9
  and 10) of this report contains representations of the lock-picking
  apparatus, from which we have copied our figures.

Soon after the picking of the Chubb lock in Great George-street, and
consequent on the excitement and discussion to which that operation led,
a committee, consisting of Mr. G. Rennie, Professor Cowper,[9] and Dr.
Black, agreed to superintend the arrangements for a more severe testing
of Mr. Hobbs’s power to open locks. There had been for many years
exhibited in the window of Messrs. Bramah’s shop, in Piccadilly, a
padlock of great complexity and beauty; to which an announcement was
affixed, that a reward of two hundred guineas would be given to any
person who should succeed in picking that lock. This challenge was
accepted by Mr. Hobbs; and the committee managed all the arrangements,
as arbitrators between Mr. Hobbs on the one side and Messrs. Bramah on
the other. The lock was removed to an upper room in Messrs. Bramah’s
establishment; where it was placed between two boards, and so fixed and
sealed, that no access could be obtained to any part of it except
through the key-hole. The room was to be given up to Mr. Hobbs; he was
not to be interrupted by the presence or entrance of any other persons;
and he was allowed a period of thirty days for opening the lock. If the
lock was not picked at the expiration of that period, Mr. Hobbs was to
be considered as having failed in his attempt.

  [9] In mentioning the name of the late Professor Edward Cowper, we
  cannot refrain from deploring the loss which mechanical science has
  suffered by his too-early death. The application of mechanical
  principles to manufactures was treated by him in his lectures and
  illustrations with a felicity which has been rarely equalled.

There was much negotiation and correspondence before and during Mr.
Hobbs’s operation on this lock. On July 2, he, with a view to this
enterprise, applied for permission to take wax impressions of the
key-hole. This permission being given, and the parties having met to
discuss the necessary arrangements, an agreement was signed on the 19th,
reciting the terms of the challenge, and providing that thirty days
should be allowed to Mr. Hobbs to effect his enterprise; that the lock
should be secured in a certain specified way; and that the key should
remain in the possession of Messrs. Bramah, who were to retain the right
of using it in the lock when Mr. Hobbs was not at work. Messrs. Bramah
subsequently relinquished this last-mentioned privilege, in order that
the trial might be perfectly fair; and it was agreed that the key should
be sealed up during the whole period, beyond the reach either of Mr.
Hobbs or Messrs. Bramah; and that the key-hole should be secured by an
iron band, sealed, when Mr. Hobbs was not at work. These and other
conditions were embodied in the agreement noticed in the last paragraph.

Mr. Hobbs commenced his labours on July 24th. After a few visits to the
lock, Messrs. Bramah wished to have the privilege of inspecting it, or
else that such an inspection should be made by the arbitrators; and,
during a correspondence which arose out of this request, the operations
were suspended. Mr. Hobbs resumed his work on August 16. On the 23d,
Messrs. Bramah drew the attention of the arbitrators to the challenge,
that the reward of two hundred guineas was offered to the artist who
should make an instrument that would pick or open the lock; that he was
to be paid the money on the production of the instrument; and that,
unless some person were present, it was impossible that any one could
know that the lock had been opened by the instrument which might be
produced. This letter was not allowed by the arbitrators to affect the
arrangements made. We may now consistently give the “Report of the
Arbitrators.”

“Whereas for many years past a padlock has been exhibited in the window
of Messrs. Bramah’s shop, in Piccadilly, to which was appended a label
with these words: ‘The artist who can make an instrument that will pick
or open this lock shall receive two hundred guineas the moment it is
produced;’ and Mr. Hobbs, of America, having obtained permission of
Messrs. Bramah to make trial of his skill in opening the said lock,
Messrs. Bramah and Mr. Hobbs severally agreed that George Rennie, Esq.,
F.R.S., of London; and Professor Cowper, of King’s College, London; and
Dr. Black, of Kentucky; should act as arbitrators between the said
parties.

“That the trial should be conducted according to the rules laid down by
the arbitrators, and the reward of two hundred guineas be decided by
them; in fine, that they should see fair play between the parties.

“On July 23 it was agreed that the lock should be enclosed in a block of
wood, and screwed to a door, and the screws sealed, the key-hole and the
hasp only being accessible to Mr. Hobbs; and, when he was not operating,
the key-hole was to be covered with a band of iron and sealed by Mr.
Hobbs, that no other person should have access to the key-hole. The key
was also sealed up, and was not to be used until Mr. Hobbs had finished
his operations. If Mr. Hobbs succeeded in picking or opening the lock,
the key was to be tried; and if it locked and unlocked the padlock, it
should be considered as a proof that Mr. Hobbs had not injured the lock,
but had fairly picked or opened it, and was entitled to the two hundred
guineas.

“On the same day, July 23, Messrs. Bramah gave notice to Mr. Hobbs that
the lock was ready for his operations.

“On July 24 Mr. Hobbs commenced his operations; and on August 23 Mr.
Hobbs exhibited the _lock opened_ to Dr. Black and Professor Cowper (Mr.
Rennie being out of town). Dr. Black and Mr. Cowper then called in Mr.
Edward Bramah and Mr. Bazalgette, and shewed them the lock opened; they
[the last-named two gentlemen are of course meant] then withdrew, and
Mr. Hobbs locked and unlocked the padlock in presence of Dr. Black and
Mr. Cowper.

“Between July 24 and Aug. 23 Mr. Hobbs’s operations were for a time
suspended; so that the number of days occupied by Mr. Hobbs was sixteen,
and the number of hours he was actually in the room with the lock was
fifty-one.

“On Friday, Aug. 29, Mr. Hobbs again locked and unlocked the padlock in
presence of Mr. G. Rennie, Professor Cowper, Dr. Black, Mr. Edward
Bramah, Mr. Bazalgette, and Mr. Abrahart.

“On Saturday, Aug. 30, the key was tried, and the padlock was locked and
unlocked with the key, by Professor Cowper, Mr. Rennie, and Mr.
Gilbertson; thus proving that Mr. Hobbs had fairly picked the lock
without injuring it. Mr. Hobbs then formally produced the instruments
with which he had opened the lock.

“We are, therefore, unanimously of opinion, that Messrs. Bramah have
given Mr. Hobbs a fair opportunity of trying his skill, and that Mr.
Hobbs has fairly picked or opened the lock; and we award that Messrs.
Bramah and Co. do now pay to Mr. Hobbs the two hundred guineas.

  GEORGE RENNIE, _Chairman_.
  EDWARD COWPER.
  J. R. BLACK.

  Holland Street, Blackfriars,
  Sept. 2, 1851.”

It may be here stated, in reference to the space of time during which
the operations were being conducted, that the actual opening of the lock
occurred much earlier, so far as concerned the principle involved,
though not in a way to meet the terms of the challenge. On his fifth
visit, Mr. Hobbs succeeded in adjusting the slides and moving the
barrel, preparatory to withdrawing the bolt; but the instrument with
which the barrel was to be turned round, being too slight, slipped, and
defeated the operation. Mr. Hobbs had then to readjust the barrel, and
to make a new instrument to aid him; this new instrument, when
completed, enabled him to open the lock in the space of an hour or two.

On the same day Messrs. Bramah addressed a letter to the arbitrators,
stating the reasons which induced them to think that, though Mr. Hobbs
had succeeded in opening the lock, the manner of doing so did not come
within the meaning of the challenge originally made by them. The
arbitrators, however, were unanimous in their award, and Messrs. Bramah
bowed to it.

In an article written in one of the daily newspapers immediately after
the opening of the lock, the following notice was given of the lock and
its production: “We were surprised to find that the lock which has made
so much noise in the world is a padlock of but 4 inches in width, the
body of it 1¹⁄₄ inches thick, and its thickness over the boss 2³⁄₄
inches. Upon opening the outer case of the lock, the actual barrel
enclosing the mechanism was found to be 2¹⁄₄ inches in length and 1¹⁄₂
inches in diameter. The small space in which the works were confined,
and its snug, compact appearance was matter of astonishment to all
present. The lock and key were made forty years since by the present
head of the eminent firm of Messrs. Maudslay and Co., Mr. Maudslay being
at that time a workman in the employ of Mr. Bramah.”

We may here remark, as indeed has been remarked in former pages, that
the Bramah lock is, and will probably continue to be, deservedly
celebrated for the amount of mechanism contained in a small space, as
adverted to in the last paragraph. The cylindrical form is well
calculated for this concentration of power within narrow limits; and the
smallness of the key is a great merit.

The objections made by Messrs. Bramah to the award of the committee
were embodied in the following letter to Mr. Rennie, dated 9th
September:

  “DEAR SIR,--We beg to acknowledge your letter of yesterday’s date, and
  will not trouble you to attend here to-morrow, but beg to hand you the
  210_l._ awarded by the arbitrators to Mr. Hobbs. We need scarcely
  repeat that the decision at which the arbitrators have arrived has
  surprised us much; and we owe it to ourselves and the public to
  protest against it. We do so for the following reasons:

  “1. Because the arbitrators, having been appointed to see fair-play,
  and that the lock was fairly operated upon, did not, although
  repeatedly requested in writing to do so, once inspect or allow any
  one to witness Mr. Hobbs’s operations during the sixteen days he had
  the sole custody of the lock and was engaged in the work.

  “2. Because the arbitrators did not once exercise their right of using
  the key, although repeatedly requested in writing to do so, till after
  Mr. Hobbs had completed his operations; and then, instead of applying
  at once to prove that no damage had been done to the lock, allowed him
  twenty-four hours to repair any that might have occurred.

  “3. Because the lock being opened by means of a fixed apparatus
  screwed to the wood-work in which the lock was enclosed for the
  purpose of experiment (which it is obvious could not have been applied
  to an iron door without discovery), and the addition of three or four
  other instruments, the spirit of the challenge has evidently not been
  complied with.

  “4. Because from the course adopted an opportunity of some good
  scientific results has been taken from us; as neither arbitrators nor
  any one else saw the whole or even the most important instruments, by
  which it is said the lock was picked, actually applied in operation,
  either before or after the lock was presented open to the arbitrators.

  “5. Because during the progress of Mr. Hobbs’s operations, and several
  days before their completion, we called the attention of the
  arbitrators to what we considered the interpretation of the challenge,
  begging at the same time that they would apply the key and appoint
  some one to be present during the residue of the experiment; feeling
  that whatever might be the result in a scientific point of view, the
  reward could not be awarded.

  “We would add, that we think that several points which appear in your
  minutes should not have been mentioned in your award; more especially
  that Mr. Hobbs on the 2d of June took a wax-impression of the lock,
  and had made, as far as he could, instruments therefrom between that
  date and the commencement of his operations.

  “We are, dear sir,

  “Your obedient servants,

  “BRAMAH AND CO.”

In order that the opinions of Messrs. Bramah and others may be given
with as much fairness as possible, on a matter which they could not feel
but otherwise than important to them, we may state, that among the
letters to which the picking of the Bramah lock gave rise in the public
journals, was the following addressed to the _Observer_ newspaper on
10th October:

  “SIR,--This controversy having excited an unusual degree of public
  attention for some time past, perhaps you will be good enough to allow
  us to state in your journal, that the lock on which Mr. Hobbs operated
  had not been taken to pieces for many years, and it was only on
  examining it (after the award of the committee) that we discovered the
  startling fact, that in no less than three particulars it is inferior
  to those we have made for years past. The lock had remained so long in
  its resting-place in our window that the proposal of Mr. Hobbs
  somewhat surprised us. After his appearance, however, no alteration
  could of course be made without our incurring the risk of being
  charged with preparing a test-lock for the occasion; we were therefore
  bound in honour to let the lock remain as Mr. Hobbs found it when he
  accepted the challenge. No one inspected his operations during the
  sixteen days he had the sole custody of the lock and was engaged at
  the work. We are therefore compelled to advertise another 200 guineas,
  in order that we may see the lock operated upon and opened, if it be
  possible; and thus gain such information as would enable us to use
  means that would defy even the acknowledged skill of our American
  friends. We believe the Bramah lock to be impregnable; and we cannot
  open it ourselves, with the knowledge Mr. Hobbs has given us. We have
  fitted up the same lock with such improvements as we now use, and some
  trifling change suggested by the recent trial, and restored it with
  its challenge to our window. We have not done this in a vain, boasting
  spirit; on the contrary, we feel it rather hard that, from the way in
  which the former trial was conducted, we are driven to adopt this
  course. Had any one inspected Mr. Hobbs’s operations during that
  trial, it would not have been necessary.

  “We are, sir, &c.,

  “BRAMAH AND CO.”

Messrs. Bramah are well entitled to offer any explanation concerning the
relative perfection of the lock in question, and of one that they could
now produce with certain improvements in some parts of the working
mechanism; but if these improvements do not involve any new invention,
patented or otherwise,--that is, if the lock be really a carrying out of
the contrivances already made public,--it is difficult to see why it
should not yield to the same treatment as the other. It is true that,
shortly after the decision of the arbitrators, Messrs. Bramah exhibited
a new lock in their window, and repeated their challenge in the same
terms as before, with the single addition, that applications were to be
made in writing only. We have reason to know that an application was
made, and that the consequence was the withdrawal of the challenge. In
respect to the actual contest, however, the character and position of
the arbitrators ought surely to hold Mr. Hobbs justified in his
proceedings. They were not all Americans (supposing nationality to give
a bias in the matter); two were Englishmen, both of distinguished rank
in respect to mechanical knowledge; and as Mr. Hobbs was as much bound
by their decision as Messrs. Bramah, he was entitled to claim any
advantage resulting from a favourable decision.

The following is a description, so far as can be given in words, of the
mode in which Mr. Hobbs operated on the Bramah lock. The first point to
be attained was to free the sliders from the pressure of the spiral
spring; the spring was very powerful, pressing with a force of between
30 and 40 lbs.; and until this was counteracted, the sliders could not
be readily moved in their grooves. A thin steel rod, drilled at one end,
and having two long projecting teeth, was introduced into the key-hole
and pressed against the circular disc between the heads of the sliders;
the disc and spring were pressed as far as they would go. In order to
retain them in this position, a curved stanchion was screwed into the
side of the boards surrounding the lock, and the end brought to press
upon the steel rod, a thumb-screw passing through the drilled portion of
the instrument and keeping it in its place. The sliders being thus freed
from the action of the spring, operations commenced for ascertaining
their proper relative positions. A plain steel needle, with a moderately
fine point, was used for pushing in the sliders; while another with a
small hook at the end, something like a crochet-needle, was used for
drawing them back when pushed too far. By gently feeling along the edge
of the slider, the notch was found and adjusted, and its exact position
was then accurately measured by means of a thin and narrow plate of
brass, the measurements being recorded on the brass for future
reference. The operator was thus enabled, by this record, to commence
each morning’s work at the point where he left off on the previous day.
The lock having eighteen sliders, the process of finding the exact
position of the notch in each was necessarily slow. Mr. Hobbs employed a
small bent instrument to perform the part of the small lever or bit of
the key; with this he kept constantly pressing on the cylinder which
moved the bolt. He thus knew that if ever he got the slide-notches into
the right place, the cylinder would rotate and the lock open. He could
feel the varying resistance to which the sliders were subjected by this
tendency of the cylinder to rotate; and he adjusted them one by one
until the notch came opposite the steel plate. The false notches added,
of course, much to his difficulty; for when he had _partially_ rotated
the cylinder by means of the false notches, he had to begin again to
find out the true ones.

This description accords pretty nearly with that given in a former page;
but we reproduce it here to shew not merely what _might_ be the process
adopted, but what really _has been_ done. One circumstance ought at
least to be noted in these transactions--there is no mystery; the method
adopted is the result of a process of reasoning candidly and openly
explained.

In justice to Messrs. Bramah we thought it our duty to give them an
opportunity of stating what improvements they had made in their locks
since the date of the Great Exhibition; and accordingly, on the 28th
April, 1853, our publisher addressed to Messrs. Bramah a note, stating
that a _Rudimentary Treatise on the Construction of Locks_ was being
prepared, and inviting them to contribute thereto. The following is a
copy of their reply:

  “124 Piccadilly, May 2d, 1853.

  “SIR,--Pressure of business has prevented our sending an earlier reply
  to your favour of the 28th ult.

  “The lock on which Mr. Hobbs operated during the Great Exhibition had
  been made nearly forty years, and when taken to pieces the sliders
  were found to be in iron, instead of steel; and the key-hole of the
  lock being three times larger than it ought to have been, enabled the
  operator to fix down the spring of the lock, and yet leave himself
  ample space to turn and bend the sliders (being in iron) at pleasure.
  The barrel of the lock in which the sliders act, instead of being
  whole length from front to back of padlock, was not quite half its
  proper length; a serious oversight in the workman who put the lock
  together, as the barrel being short, the sliders were necessarily so,
  which diminished the number of notches in the sliders full one-half,
  and to that extent diminished the security of the lock, and increased
  the facility of the operator.

  “We send for your inspection a box of guards, which will shew you the
  barrel and sliders of our Bramah lock. You will observe several
  notches in each slider, only one of which will turn on the
  locking-plate, the others being what are termed false, or security
  ones. These notches being cut only the exact width of the
  locking-plate, require the most perfect accuracy to carry each down to
  its proper distance. In the lock on which Mr. Hobbs operated, in
  addition to the sliders being so short, and only half the number of
  security-notches in each, the notch which passed round the
  locking-plate was found to be cut twice the width it ought to have
  been. The whole of these defects have been corrected since the
  Exhibition.

  “We are, Sir, yours respectfully,

  “BRAMAH and Co.

  “per J. SMYTH.

  “To John Weale, Esq., 59 High Holborn.”

In the Jury Report of the Great Exhibition, Class XXII., are the
following remarks: “On the comparative security afforded by the various
locks which have come before the jury, they are not prepared to offer an
opinion. They would merely express a doubt whether the circumstance that
a lock has been picked under conditions which ordinarily could scarcely
ever, if at all be obtained, can be assumed as a test of its
insecurity.” [page 500]. The conditions here alluded to probably refer
to the free access which Messrs. Bramah allowed Mr. Hobbs to have to
their lock during a period of thirty days, and we are hence led to infer
that the burglar is denied any such facilities. On this point we would
refer to the opinion of a high authority. In a paper “on the History and
Construction of Latches and Locks,” by Mr. Chubb, read before the
Society of Arts, 22d January, 1851, the following graphic passage
occurs:

“In order to shew the absolute necessity of secure locks and safe
depositories for property, especially in banking establishments, it may
not be out of place to trace the systematic care and great sagacity with
which the large burglaries are planned. You will bear in mind that an
unsuccessful attempt is seldom made where the booty is of any magnitude.
The first-rate ‘cracksmen’ always know beforehand where to go, when to
go, and what they are going for. When a ‘plant,’ as it is termed, is
made upon a house or a bank, precise information is gained, if possible,
as to the depository of the valuables; and if it is found that the
safeguards are too strong in themselves, and that the locks are
invulnerable, the affair is quietly dropped. But if otherwise, then no
expenditure of time or misapplied ingenuity is spared to gain the
desired end. The house is constantly watched, the habits of its inmates
are observed, their ordinary times of going out and coming in are noted;
the confidential servants are bribed or cajoled, and induced to leave
the premises when their employers are absent, so that impressions may be
taken from the locks, and false keys made. When all the keys required
are made, one or two men who have not been previously initiated are
generally called in, and receive their instructions to be ready at a
certain hour on the following day to enter the house. A plan of the
premises is put into their hands, they are cautioned to step over a
certain creaking stair or plank, and the keys of the different doors are
given them. The day or evening is chosen when it is known that the
inmates will be from home--the servant, taking advantage of their
absence, fulfils a long-standing engagement with his new and liberal
friends--a signal is given--the two confederates enter--the so-called
safe is swept of its contents, all the doors are carefully re-locked,
and not until the bank is opened for business next morning is the
robbery discovered.”

In an article in _Frazer’s Magazine_ for November 1852 the following
observations were made on the Exhibition Jury Report on Locks: “This
jury seems to have consisted of the only persons in England who did not
hear of the famous ‘lock controversy’ of last year; for one can hardly
imagine that, if they had heard of a matter of so much consequence to
the subject they were appointed to investigate, they would have
altogether abstained from saying any thing about it. They may be excused
for not knowing, because very few people did know, fortunately for our
safes and strong boxes, that the mode of picking Bramah’s and Chubb’s
locks, by which the transatlantic Hobbs gained so much glory, was
suggested and explained in the _Encyclopædia Britannica_ nearly twenty
years ago. But it does seem very strange that they, or at least their
reporter, should not have known, long before the Report finally left his
hands, that Hobbs had picked both of those locks, and taught every
lock-picker in England how to do it, if he possesses the requisite tools
and fingers. Of course, however, the reporter did not know it, as nobody
could read any newspaper last autumn without knowing it. And this jury
did exercise their judgment to the extent of declaring that Hobbs’s own
lock (under the name of Day and Newell) ‘seems to be impregnable.’
Notwithstanding all which, they express their inability to ‘offer any
opinion on the comparative security afforded by the various locks that
have come before them.’ The only discrimination which they venture to
make is, that the keys of Bramah’s and Chubb’s locks are of convenient
size, while Hobbs’s is ponderous and bulky, and his lock complicated;
and they might have added (without any very painful amount of
investigation), enormously expensive, in consequence of its
complication, and probably also more likely, on the same account, to get
out of order and stick fast, and so become rather inconveniently
impregnable--on the money door of a bank, for instance,--than the other
two locks, especially Bramah’s.”

In relation to the opinion just given, it may be remarked that the
American lock has shewn no tendencies to get out of order; if well
constructed (and good construction is a _sine qua non_ in such
mechanism), the parts work into and upon each other with very little
friction. In respect to expense, and to the size of the key, a
_bank_-lock is not one in which economy would be much studied, security
being the great desideratum. No attempt is made to produce a parautoptic
lock of small size or for cheap purposes. The lock, therefore, must be
judged of with reference to what it undertakes to perform. And this
brings us to notice the attempts made in England to pick the parautoptic
or American bank-lock.

The following were the circumstances connected with Mr. Garbutt’s
attempt to pick the American lock. It is of course known that a
challenge was affixed to the American lock in the Great Exhibition, and
it was this challenge which Mr. Garbutt accepted. Mr. Garbutt, it may be
here observed, was a working locksmith and engineer; he had been
entrusted by Messrs. Fox and Henderson with the care and adjustment of
the metal check-tables at the pay-places of the Crystal Palace; he had
at a previous period been in the employ of Messrs. Bramah. We mention
these facts only on account of an erroneous rumour at the time that he
was an agent of Messrs. Bramah in respect to the acceptance of the
American challenge; whereas we believe he acted independently, by and
for himself.

On Sept. 10th, 1851, Mr. A. H. Renton, Mr. E. H. Thomson, and Mr. W. F.
Shattuck,--the first an engineer, and the other two American
exhibitors,--were appointed arbitrators to superintend the arrangements,
and they met Mr. Garbutt and Mr. Hobbs at the house No. 20
Knightsbridge. The following conditions were agreed to:--That a Newell
lock should be selected, and should be screwed to a wooden box; that Mr.
Garbutt should have access only to the key-hole of the lock, through
which key-hole all his operations for picking the lock should be
conducted; that Mr. Garbutt should have uninterrupted and exclusive
access to the box, between the hours of nine in the morning and nine in
the evening, for thirty days, beginning on the 11th of September, he
having during that time the privilege of introducing one associate, and
the arbitrators reserving to themselves the right of inspecting the
seals placed by them on the box; that, in order to afford every
information concerning the internal arrangement of the lock, the
trial-lock should be taken to pieces in presence of all the parties;
that it should be examined by Mr. Garbutt; that it should be locked and
unlocked with the proper key by him and by Mr. Hobbs; that it should be
fastened to a box, and the fastenings sealed by the arbitrators; that
the key, when the lock was finally locked, should be sealed up by the
arbitrators and delivered to Mr. Hobbs, who would retain it until
required by the arbitrators to hand it over to them. That at the
expiration of the thirty days, or earlier in case either of the success
or the abandonment of the attempt, the arbitrators should examine the
lock. And, finally, that if Mr. Garbutt should have succeeded in picking
the lock (that is, in withdrawing the bolt without injuring the lock),
the sum of 200_l._ should be paid to him by Mr. Hobbs.

In accordance with the above agreement, Mr. Hobbs produced a parautoptic
lock, with ten tumblers, marked No. 8560. The key and the lock were
examined by Mr. Garbutt. The lock was again put together, affixed to a
box, and sealed. Mr. Hobbs set the bits of the key (ten in number) to an
arrangement chosen by himself, and the lock was then locked by all
parties in succession; the key, after the final locking, being sealed up
and returned to Mr. Hobbs. Mr. Hobbs at the same time delivered to Mr.
Garbutt a similar but smaller lock, which he was to be allowed to retain
during the whole period of the trial, to assist in rendering him
familiar with the construction of both locks.

On the 11th of October, the day on which the prescribed period expired,
the arbitrators met at the house in question, when Mr. Garbutt delivered
up to them the lock uninjured, but _unopened_. The award of the
arbitrators was thereupon given in the following terms: “We therefore
hereby certify that Mr. Garbutt having had uninterrupted and exclusive
access to the lock during the period of thirty days, and, availing
himself of the conditions of the agreement, had every facility for
opening the lock that could be obtained without possession of the true
key, has delivered up the same into our hands unopened and uninjured;
and the said lock has been delivered by us to Mr. Hobbs.”

It will of course be understood that it was one condition of this
enterprise, that the particular combination of bits in the key wherewith
the lock was finally locked should not be seen by Mr. Garbutt. The key
was in the first instance tried by Mr. Garbutt and by the members of the
committee, and was found to turn readily in the lock; Mr. Hobbs then
left the room, and re-arranged the bits of the key so as to produce a
new combination; he then returned to the room, and locked the lock with
the key in its altered form; he allowed all present to feel the key turn
freely, and then, without allowing any one to see the combination,
wrapped the key up in paper, in which it was sealed as above described.
Whether Mr. Garbutt, or any one, could have succeeded better by a
momentary glance at the arrangement of the key, was not at that moment
the question: the terms of the challenge were that he should _not_ see
it. What are the circumstances likely to occur if the operator really
has access to the key (provided the bits are not very numerous) we may
shortly explain.

It is necessary to draw a distinction between _picking of a lock_ and
_ringing the changes on a permutating key_; otherwise some of the late
occurrences connected with locks can hardly be understood. After the
reading of a paper by Mr. Hobbs before the Society of Arts, a discussion
arose, in which it was stated that the Newell lock had been picked in
London. Mr. Hobbs deemed it necessary to refute this statement. The
report was circulated in many of the London newspapers; and Mr. Jeremiah
Smith, the operator in question, supported it by his own statement.
Under these circumstances Mr. Hobbs, on April 2, 1852, addressed a
letter to the editor of the _Observer_; of which the following paragraph
was intended to point out the distinction above mentioned between
“picking” and “ringing the changes:”

“Early last autumn I lent to Mr. Potter, of South Molton Street, one of
my locks, for the purpose of giving him an opportunity to make himself
acquainted with its principle and construction. After he had had the
lock in his possession several weeks, a report reached me that one of
Mr. Potter’s workmen had picked my lock. I immediately called on Mr.
Potter to ascertain the fact. Mr. Potter informed me that for the
purpose of testing the possibility of opening the lock by means of an
impression taken, or a copy being made of the true key, Mr. Smith had
made a copy of the key by means of a transfer instrument, which
instrument he shewed me at the time. After the key was made, it was
tried, and found to lock and unlock the lock as readily as the original
key. Mr. Potter then sealed the screws of the lock, changed the
combination of the key, and locked it. Mr. Smith then took the lock, and
with the key that he had made by copying the original, hit the
combination, and unlocked it. The lock was of the smallest size, having
but six tumblers; the number of changes that could possibly be made were
720. The time occupied by Mr. Smith, according to his own statement, was
six hours and fifty-five minutes; this, allowing one minute for each
change, would give him time to have made 415 out of the 720 changes
before hitting the right one. I asked Mr. Smith why he did not use the
original key instead of making a copy? His answer was, that ‘he could
change the one he made faster, as he did not have to screw the bits in.’
Any person will readily understand the difference between ringing the
combination of a key and picking a lock.”

In other words, the process was this: the operator had the true key, and
might have used either this or one which he made from it. This would
have sufficed for opening almost any lock ever constructed instantly;
but in the American lock he had to find out which of 720 combinations
was the right one, and he was employed almost seven hours in doing
this. The exploit shewed patience, but had little bearing on the
practical subject of lock-picking.

In March 1852 Mr. Smith put forth an offer to accept the challenge made
by Mr. Hobbs in respect to the Exhibition lock. Mr. Hobbs agreed to the
offer, and chose, as arbitrators on his part, Mr. Hensman, Engineer to
the Bank of England, and Mr. Appold, inventor of the centrifugal pump
which attracted so much attention at the Great Exhibition. Mr. Hobbs
requested Mr. Smith to appoint arbitrators on his side also; but this
was not done. Mr. Smith, at a meeting held by the four persons named,
expressed a wish that an ordinary commercial lock should be the one
experimented on, instead of the more complicated test-lock which had
been at the Great Exhibition. This was a departure from the terms of the
original challenge; but Mr. Hobbs waived his objection on this point,
and offered to substitute a bank-lock with ten tumblers for the
Exhibition lock with fifteen, the former being similar in construction
but less complex. Another meeting was agreed upon, but Mr. Smith did not
attend; and the matter was, by himself, brought to a sudden termination.

To shew the effect of difference in the number of tumblers and key-bits,
we may state that, while, at a minute per change, it would take twelve
hours to go through all the combinations with a six-bitted key, it would
require seven years with a ten-bitted, and 2,500,000 years with a
fifteen-bitted key! So much for power of combination, in the
arithmetical mode of picking.

We now proceed to notice the violability of sundry minor locks. It might
at first appear that the _letter-lock_ is exceedingly difficult to pick;
and so it unquestionably is, as long as we merely attend to the
chance-medley trials by turning the rings round and round until we
happen to hit upon the right combination. But there is another mode of
solving the riddle, mechanical rather than arithmetical. A piece of
common wire, bent in the form of the shackle, is put in between the ends
of the lock; the spring or elasticity of the wire tends to force the
ends apart; this causes the pins or studs on the rod to press against
the inner edges of the rings. By trying all the rings in succession,
some one of them will be found to bind or cling more than the others;
this is turned round until the cessation of the bind shews that the
notch in the ring has been brought into its right position relatively to
the pin on the rod. Then another ring which binds more than the rest is
treated in a similar way; until at length all the rings seem to be so
far liberated as to indicate that the notches are in the right
positions. In the dial-lock, similarly, when a pressure has been brought
to bear upon the bolt in the right direction, a trial of the pointers
will soon bring the notch in each wheel to the required position.

Some short time after the events in London connected with the lock
controversy, Mr. William Brown of Liverpool described the letter-lock
noticed in a former page, characterising it as a lock which he believed
no one could pick. An incident in the history of this lock was thus
narrated in one of the Liverpool newspapers. “Mr. Hobbs was taken by Mr.
Milner to the office of Messrs. Brown, Shipley, and Co., and shewn this
lock. The safe-door was closed and locked by the cashier at Mr. Brown’s
request; and then Mr. Hobbs began to illustrate his views of the
construction of the lock by manipulation and explanation, with which the
subject of them appeared to sympathise so entirely and promptly that the
door opened in a few minutes.”

In respect to the picking of the Egyptian lock, the main difficulty
would be in obtaining any false key that would correspond with the pins
of the lock; but this might be accomplished in a way analogous to that
which is practised in many other cases. If a small piece of wax be laid
on a blank key, the key inserted into the lock, and the blank pressed
upwards against the pin-holes, there would be left an impression of
those holes on the wax; this impression would furnish a guide to the
fabrication of a false key. There is also very little difficulty in
picking this lock by one of the ordinary instruments.

For the Yale lock, combining something like the pin-action of the
Egyptian with the cylinder-action of the Bramah locks, the picking
requires the use of an instrument that will fit between two of the pins,
and to the outer end of which is attached a lever and weight; by this
means a pressure is exerted upon the cylinder in the right direction for
it to turn, and the pins are made to bind. Then, with another
instrument, the pins are felt, and each one moved until it seems to be
relieved from the bind: this indicates that the joint in the pin
coincides with the joint between the two cylinders; and when all have
been similarly treated, the weight acting on the inner cylinder will
turn it. It is evident that this method is the same in principle as the
one applicable to the Bramah lock.




CHAPTER X.

EFFECTS OF THE GREAT EXHIBITION OF 1851 IN IMPROVING ENGLISH LOCKS.


We have now to refer to the effects of the lock controversy. It was no
doubt annoying to be told, on good authority, that the machines on which
we so much prided ourselves were wrong in principle; and that our locks,
in order to afford the degree of security which are expected of such
contrivances, must be re-constructed. The grumbling with which the first
part of this proposition was received would alone have sufficed to lead
to a suspicion of its truth, if the large number of new locks that have
actually appeared had not confirmed it. Whether the second part of the
proposition has been fairly carried out, is a point which must now be
considered.

One of the first locks produced during or immediately after the lock
controversy was Mr. Parnell’s, to which the bold term of _patent
defiance lock_ is attached. This lock is said to depend for its security
on a mode of arrangement which may best be described in the inventor’s
own words: “Viewing the lock from its exterior, it presents nothing
remarkable; but, upon removing the plate, it will be seen that all
possible access to the mechanism with false or surreptitious keys is
effectually prevented by a solid cylinder of _hardened_ [?] brass, with
protecting wards extending the whole depth of the lock, and having in
the centre the aperture for the key, which fits to a mathematical nicety
so exact as to preclude the possibility of any second instrument being
used to open it.... This protecting cylinder must revolve with the key
to get to the works; and the moment it passes from the key-hole in going
round to lock or unlock, the solid portion moves into its place, and so
completely closes that aperture that the point of a pin, or a fine
steel-pen, has failed to be inserted between it and the outer plate or
cap, to say nothing of the utter hopelessness of perforating the metal.

“The cylinder or protecting cap, though it revolves by the action of the
key somewhat in the same way as the cylinder of the Bramah lock, appears
to be intended rather for closing or protecting the key-hole than for
governing the movements of the bolt. The internal arrangements of the
lock are as follow: Supposing the bolt to be shot, and to be about to be
unlocked, the key, by the time it has made about one-third of a
rotation, meets with a forcible resistance in the shape of an upright
spring-bolt or detector of strong steel acting on the revolving
cylinder. The key passes this detector, and arrives at the levers or
tumblers. In the bolt-stud which works in the slot of these tumblers
there is a small deep serrated notch on one side, corresponding to
similar notches on each of the tumblers; if, therefore, the bolt be
forced, these notches would lock into each other in a similar manner to
the catch on a ship’s windlass or a hoisting crane. There is also a
double-action tumbler-bolt, so adjusted, that if any of the tumblers be
overlifted, this little appendage becomes thrust down at one end into
the bolt of the lock, where it wedges all fast until the tumblers
become properly re-adjusted. The double-action tumbler-bolt also falls
into the lock-bolt when the latter is locked or shut, thereby imparting
an additional strength to the lock. The key has a power of expansion or
enlargement while turning in the lock; it meets with an eccentric plate
which draws out the bits somewhat; so that, at the moment of acting on
the tumblers, they protrude farther from the pipe of the key than when
the key entered the key-hole. The key is, in fact, larger when in than
when out of the lock. There is connected with the works of the lock a
‘detention-cap,’ so formed that, in the event of a false key being used,
a powerful bolt instantly locks into the revolving cylinder, and holds
fast the surreptitious instrument.” Such is, in substance, the account
which Mr. Parnell has given of his own lock. It must, however, be
stated, that the points of security or novelty claimed by Mr. Parnell
for his lock were patented by previous inventors. The revolving cylinder
or curtain was claimed by Mitchell and Lawton in the patent of 7th
March, 1815, as noticed at page 52 _ante_. The expanding key-bit was
claimed by Mr. Machin of Wolverhampton in 1827, as noticed at page 61,
and by Mr. Mackinnon (page 62); while the serrated notches in the
tumbler were used by many lock-makers long before the date of Mr.
Parnell’s patent. The detention-cap for catching and holding a false key
when put into the lock was also patented by Mitchell and Lawton, as
noticed at page 53 _ante_.

We come now to notice a lock lately invented by Mr. E. B. Denison (the
author of the _Rudimentary Treatise on Clocks_ in this series), which
has the merit of combining considerable novelty in construction with
security. After the details given in the two preceding chapters, it will
certainly be no small praise when we express our conviction that in the
present state of the art of lock-picking, this lock may be considered as
secure. Mr. Denison has furnished us with a description of his lock,
which we insert almost in his own words. Mr. Denison claims for this
lock the following advantages:--

1. That a very large and strong lock on this construction only requires
a very small key. 2. That no key is required to lock it, although it is
free from the inconvenience pertaining to spring-locks, viz. that the
door cannot be shut without locking itself. Moreover this lock is more
secure than any spring-lock can be. 3. That it cannot get out of order
from the usual causes of the tumblers sticking together or their springs
breaking, inasmuch as the action of the tumblers does not depend on any
thing but the key and the handle, and there are no tumbler-springs. 4.
That for the same reason, the parts of this lock do not require any
polishing or delicacy of execution. 5. That the key-hole being
completely closed by a curtain, except when the key is in, the lock is
protected from the effects of the atmosphere and dust entering at the
key-hole. 6. That this lock is secure against any known mode of picking;
the smallness of the key-hole prevents the insertion of any instrument
strong enough to open the lock by violence. 7. That this lock, from the
simplicity of its construction, admits of being made at small cost.

These objects are accomplished as follows:--In the large-sized locks,
such as would be used for safes and large doors, the tumblers T, fig.
51, are made of pieces of hoop-iron, 6 or 7 inches long and 1¹⁄₂ inch
wide: these tumblers are supported by and turn on a pin _a_, placed at
about the middle of their length; so that being balanced on the pin, or
nearly so, and having their separating plates P between them, which
cannot turn, the tumblers will stand in any position indifferently; and
in order to secure sufficient friction to keep them steady, one or more
of the separating plates P is bent a little, so as to act as a spring
when the cap of the lock is screwed down. The lock is shewn in fig. 51
as locked, the bolt B having been shot by the fantailed piece _f_ on the
handle, and the tumblers sent down, so that the stump _s_ cannot enter
their jaws by the other piece of the handle; and it is evident that the
handle cannot draw the bolt back again until the tumblers have all been
raised by the key to the proper position to allow the stump _s_ to enter
their jaws. It will be observed that in the position shewn in the
figure, the stump does not touch the tumblers; and consequently, so long
as the bolt is kept in the position represented, no pressure of the
stump against the tumblers can be felt, although by means of a false key
or pick-lock the tumblers be raised to any height. No implement,
however, can be pushed into the key-hole without first pressing in the
curtain K, which is held up against the cap of the lock by the two
spiral springs _c c_ on each side of the key-hole; and at the back of
the curtain there is a square plug _p_, which goes through a hole in the
back of the lock, and has a notch in it through which the bolt can pass
when the curtain is up, closing the key-hole, but at no other time. In
other words, the act of pushing in the key sends down the curtain plug,
the effect of which is to hold the bolt fast in the position in which
the stump cannot be made to touch the tumblers. If the proper key be
used and turned about half round to the right, it will bring the
tumblers to the proper height for the stump to pass. The key is then
taken out; for so long as it is in the lock, the bolt cannot be moved;
and then turning the handle to the right, the bolt is drawn and the door
opened.

[Illustration: fig. 51. Mr. Denison’s large lock.]

The handle H should be so made, that as soon as the fantailed piece _f_
has sent the bolt just clear of the tumblers, the other arm to the right
of H may begin to move the tumblers; but the fantail need not send the
stump above one-sixteenth of an inch beyond the tumblers; and the
curtain-plug and bolt must be so adjusted that the curtain cannot be
pushed in until the bolt is so far out that the stump is this
one-sixteenth of an inch beyond the tumblers. The curtain K need only be
a thin piece of steel, and the bolt B must be thick enough for the
curtain to go down just to the level of the thin plate P between the
bolt and the first tumbler T. The curtain-plug _p_ is made as long as
the key-hole and rather broader, and of the shape represented, partly
for the sake of steadiness in pushing in the curtain, and also for more
completely protecting the key-hole; for if an attempt be made to pick
the lock by drilling into the key-hole, the drill will pass into the
inside of the door and not into the inside of the lock.[10]

  [10] Mr. Denison informs us that there is a further contrivance, which
  he will explain privately to any persons who wish to manufacture these
  locks, of which the object is, not to add any thing to the security of
  the lock under ordinary circumstances, but to provide against the
  unusual case of a very dexterous thief having occasional access to the
  lock when open; in which case (but for some such further provision) he
  might manage to construct a false key capable of opening the lock at
  any other time, by a method which, for obvious reasons, it is not
  advisable to publish.

It is true that iron safes have been made for some years in which any
number of large bolts are shot by a handle and then locked by a very
small key. But in such locks the key must be used in locking, and this
leads to certain objections, viz. the key must occasionally at least be
confided to some person whose duty it is to lock up the safe after the
owner has left the place; there is also the temptation to leave the key
in the lock, since it will be wanted in locking up; and thus there is
the danger of some dishonest person taking an impression of the key.
Besides this, the real strength and security of such safes is only that
due to the small lock which locks into the main bolt; whereas in Mr.
Denison’s lock the security and strength are those due to the lock
itself, with its large and strong tumblers, and other provisions
peculiar to its construction; and the key for a lock of the largest
size, which was lately exhibited at the Society of Arts by Messrs. S.
Mordan and Co., the makers, only weighs a little more than a quarter of
an ounce. It may be mentioned that for large locks the key may be solid,
although in the small ones it is more convenient to have a pipe-key, on
account of the different construction of the curtain.

[Illustration: fig. 52. Mr. Denison’s small lock.]

The arrangement of the small lock for drawers, &c. is somewhat different
from that of the large ones, and will be understood by referring to fig.
52. The action of the handle H on the bolt B and on the tumblers T is
sufficiently clear from the figure. The curtain in this case has no
plug, but is only a flat plate held up by a thin spring behind it, and
moving up and down on the drill-pin of the key, and kept from turning by
having one edge against the side of the lock. The bolt has a kind of
second stump, only coming up so high as to be able just to pass under
the corner of the curtain when it is up, but not able to pass when the
curtain is at all pressed down by any thing inserted in the key-hole. In
a drawer lock the key has only to be turned a quarter round in order to
raise the tumblers. In small locks, the friction of the tumbler-plates
is quite enough to keep them in any position, without putting the pin
in the middle so as to balance them, as in large locks with heavy
tumblers.

In the making of these locks the key must be made first, with proper
provisions to prevent the repetition of the same pattern; a kind of
pattern or model for locks of each size should be made; the tumblers put
on the pin with plates of the intended thickness between, and when
raised by the key to the proper height they should be clamped down; and
the jaws for the stump of the bolt may then be cut by a circular saw
moving in a slit in the model corresponding to the place of the stump.
The tumblers for large locks may be cut off from a strip of hoop-iron to
the proper lengths by a stamping cutter, giving them the proper circular
end, and a punch might at the same time make the pin-hole in the middle.
The tumblers for small locks should be stamped out of sheet brass or
iron.

It will thus be evident that from the general simplicity of
construction, and the small amount of finish required in the working
parts, this lock can be made at small cost. We may also add that this
lock is as creditable to the public spirit as to the mechanical skill of
the inventor; for the lock is not patented, patents being, in Mr.
Denison’s estimation, obstructions to the progress of science.

The next result of the “lock controversy” which we have to notice is the
production of not less than three improved locks by Messrs. Chubb. We
thought it our duty to invite the attention of this celebrated firm to
the preparation of this _Rudimentary Treatise_, and in answer to the
application of our publisher we received the following communication
from Messrs. Chubb, which we insert verbatim:--

“It will not be necessary to describe the lock as originally made, as a
description of it will be found in Mr. Chubb’s paper read before the
Institution of Civil Engineers.

“LOCK NO. 1.--The first of the improvements introduced consists of a
barrel, to which a circular curtain is attached, revolving round the
drill-pin in the lock; so that if any instrument is introduced to
attempt to pick it, the curtain immediately closes up the key-hole, and
prevents the introduction of any auxiliary instruments, there being
several required in action at once to produce any effect.

“If by any means these several instruments can be introduced
simultaneously, the barrel keeps them all confined in a very small
space, preventing their expansion, and renders it impossible to work
them independently of each other; therefore they are of no avail, being
incapable of acting as more than a single pick, which is perfectly
useless. The barrel and curtain have each been previously used
_separately_ in locks, but until patented by Mr. De la Fons in 1846 they
had not been used _in combination_. Neither of them, used separately, is
of much use, but when combined they afford a very great security. Locks
have been, and still are shewn, containing either the barrel or curtain
_singly_, and as these have been picked, it has been asserted that the
improvement now introduced in Chubb’s lock is equally insecure; but a
slight examination of the difference in their construction will prove
the contrary. Mr. Chubb has purchased the patent-right of this part of
Mr. De la Fons’ invention, and applies it to all his locks.

“LOCK NO. 2.--The next improvement, recently patented by Mr. Chubb, is
based upon the assumption that there may be a possibility of overcoming
the security of the barrel and curtain as already described (although
this assumption is not in the slightest degree admitted), and consists
in applying what is called a ‘tumbler-bolt,’ working on a hinge
connected with the main bolt. The web of the key does not in any case
touch the main bolt in unlocking, but acts only on the tumbler-bolt. All
the tumblers must first be lifted, each to its proper position, before
the tumbler-bolt will act. Should any pressure be applied to either bolt
before the tumblers are all at their exact position, the effect would be
to throw the bolts out of gear, and thus effectually to stop the stump
of the main bolt from passing through the racks of the tumblers. None of
the many plans of picking which have been suggested, such as smoked
key-blanks, thin key-bits, &c., would be of the least avail against a
lock made on this principle. Different kinds of detectors may be applied
to these locks. It is submitted that this lock, retaining all the
simplicity and durability which have distinguished Chubb’s lock for so
many years, and combining with them these important improvements,
affords a complete security against all surreptitious attempts of any
nature. Locks on the same principle are being made on the permutation
plan, with any number of tumblers, and any number of changes in
combination that may be desired.

“It has been suggested that the ‘detector,’ instead of giving additional
security to Chubb’s lock, affords a partial guidance to a person
attempting to pick it. This objection holds good to a certain extent in
these locks as originally made, in which all the tumblers had an _equal_
bearing against the detector-stump; but in the locks as now constructed
this objection is entirely obviated, by giving the tumblers an _unequal_
bearing, whereby, if an operator feels the obstruction of the
detector-stump, he cannot tell whether the tumbler which he is lifting
is raised too high, or not high enough.

“LOCK NO. 3.--For banks, Mr. Chubb has introduced what he particularly
calls his ‘bank lock.’ It contains a barrel with a series of curtains.
While the key-hole is open, all access to the tumblers from the key-hole
is completely cut off by two sliding pieces of solid metal, which fit
closely on either side of the barrel. These pieces are acted upon by an
eccentric motion, so that when the key is applied to the lock, and
turned in it, the key-hole is shut up by the revolution of the curtains,
and then only do the sliding pieces of metal move aside to allow the key
to act upon the tumblers. These pieces return to their position when the
key has passed; therefore, while the key is lifting the tumblers, all
communication is cut off from the exterior of the lock by these sliding
pieces and the series of curtains. The bolt is made in two pieces, the
main bolt never being in contact with the key, which acts only on the
talon-bolt, and by it transmits the motion to the main bolt. After the
action of locking, the talon-bolt is partly repelled, and a lever or
‘dog’ connected with it locks into a series of combinations arranged
upon the front parts of the tumblers, and holds them securely down, so
that none of them can be lifted in the least degree until the talon-bolt
is thrown forward to release them, If, therefore, any pressure be
applied to this talon-bolt, to endeavour by its help to ascertain the
combinations of the tumblers, it will only the more tightly lock them
down, and render the attempt ineffectual. By another contrivance it is
rendered impracticable to move a pick or picks round in the lock more
than a small distance, unless the tumblers could previously be all
lifted to their right positions, which can only be done by the right
key. Should one or more of the tumblers be surreptitiously raised by any
possible means, they cannot be detained in this uplifted position, for
the action of turning back the pick to try to raise another tumbler sets
in motion a lever which allows the tumblers already raised to drop to
their former position, leaving the operator just as far from the
attainment of his object as at the outset.”

Such is the statement with which Messrs. Chubb have favoured us
respecting their three new locks. We are willing to admit the
enterprising spirit which has led to their production, and the ingenuity
which has been bestowed on their construction; but whether they mark a
step in advance in the art of lock-making may perhaps admit of doubt.
With respect to the lock No. 1, we would remark, that locks with the
barrel and curtain combined were made by Mr. Aubin of Wolverhampton in
1833, and that a specimen of such a lock was exhibited on his stand of
locks in the Great Exhibition. Locks with the combined barrel and
curtain were also made and sold by Mr. Jones of Newark, N.J., as stated
at p. 104.

With respect to the lock No. 2, the object of the _tumbler-bolt_ is
evidently intended to produce the same effect as the _movable stump_ in
Mr. Hobbs’s protector-lock, fig. 47, page 100; but with greater
complexity in the construction, there is less efficiency in the action
of this part of Mr. Chubb’s lock as compared with that of Mr. Hobbs,
inasmuch as a pressure of the stump against the tumblers, corresponding
with the strength of the spring which holds the bolt in its place, can
always be produced, thereby giving friction, and affording indication as
to which tumbler it is that is in tight contact with the stump.

With respect to the barrel and curtains of lock No. 3, and all similar
contrivances, the object of which is said to be to prevent the entrance
into the key-hole of all instruments except the proper key, we would
offer the self-evident remark, that the same aperture which admits the
key will also admit some other instrument. In the case of Mr. Chubb’s
“bank-lock,” it may be questioned whether the revolving curtain, &c.
give it any advantage over the other locks already referred to which are
furnished with similar contrivances. The effect of the _talon-bolt_ in
this lock appears to be the same as that of the false notches, namely,
to hold the tumblers in the position in which they were placed when the
pressure was applied. Hence, a pressure applied to the talon-bolt
affects the parts which come in contact with the key in the act of
locking and unlocking; and this circumstance brings the lock under the
application of the principle stated at page 99, and thus, if this
principle be admitted, may render the security of the lock somewhat
questionable.

Various other locks have been brought out since the date of the “lock
controversy” in the year 1851. We would gladly notice them all, did they
shew novelty of design and mark an advance in the art of the locksmith.
We must, however, admire the ingenuity with which Mr. Hobbs’s movable
stump has been more or less adopted; but in the attempts to imitate it
the objection has not been removed, that it is possible to produce on
the tumblers a pressure or friction equal to the strength of the spring
which holds the tumblers down.

There is, however, a lock which has lately been introduced to the
public, which calls for special notice, on account of the high honours
which have been bestowed upon it. We refer to the prize lock of the
Society of Arts, London, the invention of Mr. H. J. Saxby of Sheerness,
who has received the Society’s medal and the sum of ten guineas as the
reward of his ingenuity. The interior of this lock consists of a
cylinder with four pins or slides radiating from the centre, and pressed
into the key-hole by means of spiral springs. The pins project beyond
the periphery of the wheel or cylinder, and into slots in a ring which
is affixed to the case of the lock, thereby preventing the cylinder from
being turned. On each pin is a notch, so placed that when the proper key
is inserted into the key-hole, the notches on the several pins will be
brought into a position such as will allow the cylinder to turn. The
turning of the cylinder in this, as in the Bramah lock, shoots the bolt.

A lock on precisely the same principle, but more secure in its
construction, was described by Mr. Hobbs in a paper read by him before
the Society of Arts in January 1852, when diagrams illustrative of the
same were exhibited. This paper was not reported at any length in the
journal of the Society’s proceedings; but the same paper was read by Mr.
Hobbs, March 1, 1852, before the Liverpool Polytechnic Society, and a
full report thereof, and a description of the lock in question, is given
in the “Transactions” of that Society, from September 1849 to December
1852 (8vo, Liverpool, 1853). This lock is no other than the Yale lock
already noticed at page 83, and is thus described at page 196 of the
“Transactions:”

“Another description of cylinder-lock was invented, a few years since,
by a Mr. Yale of the State of New York, U.S.A.

“The Yale lock has two cylinders, one working within the other; and they
are held together by a series of pins reaching through the cylinders
into the key-hole, which is in the centre. On the back of the inner
cylinder is a pin that fits into a slot in the bolt, and moves it as the
cylinder is turned. The pins that hold the cylinders together and
prevent the inner one from turning, are cut in two at different lengths.
The key is so made, that by inserting it into the key-hole the pins are
moved, so that the joint in the pins meets the joint between the
cylinders, and allows the inner one to be turned. But, as with the
slides of the Bramah lock, should any one of the pins be pushed too far,
the cylinder is held quite as firmly as though it had not been touched.
Some of these locks have been made with as many as forty pins; and to a
person unacquainted with the principles on which locks are picked, they
would seem to present an insurmountable barrier.

“Figure 1[11] represents the case of the lock containing the bolt A,
having a groove B, to receive the pin C on the cylinder. Figure 2 shews
the cap or top-plate of the lock, and the cylinders; D D is the outer
cylinder, that is stationary, being fastened to the plate; E E the inner
or moving cylinder; F F the four rows of pins, being cut in two at
different lengths, and reaching through the cylinders into the key-hole;
G G are the springs that press the pins to their places; C the pin that
fits into the groove and moves the bolt. Figure 3 is an end view of the
key, shewing four grooves. Figure 4 is a side view, shewing the
irregular surface of the grooves by which the pins are adjusted.

  [11] This and the following figures refer to the diagrams exhibited by
  Mr. Hobbs.

“For the purpose of picking the lock, an instrument is made that will
fit between two of the pins; to that is attached a lever and weight,
thereby getting a pressure on the cylinder and causing the pins to bind;
then with another instrument the pins are felt, and as they are found to
bind, they are pressed in until they are relieved (as they will be when
the joint comes to the right place), thereby easily opening the lock.
There is a great similarity in the operation and security of this and
the lock manufactured by Mr. Cotterill of Birmingham.”

In the _Society of Arts Journal_ for the 24th June, 1853, is a letter
from Mr. Hobbs on the subject of the prize lock, which, it appears, he
picked, “in the presence of parties connected with the Society, in the
short space of three minutes.”




CHAPTER XI.

THE LOCK AND KEY MANUFACTURE.


The manufacture of locks and keys, considered as a department of working
in iron, is one that requires, and indeed admits of, very little
description. The hammer, the file, the drill, the fly-press, are the
chief instruments employed; the iron itself being brought to something
like the desired state and form by rolling or casting, or both. But the
manufacture is interesting in its social features--in its relation to
the persons employed and the buildings occupied. One by one, several
departments of industry have progressed from the _handicraft_ to the
_factory_ system--from that system in which a man and a few apprentices
work in a small shop in the lockmaker’s garret or kitchen, to that in
which organisation is maintained among twenty or fifty or a hundred men.
Locks have scarcely yet passed out of the first stage, but there is no
good reason whatever why they should so remain; there are as many
reasons for progress in this as in other arts, and indications are not
wanting that some such progress will be made.

So far as England is concerned, the neighbourhood of Wolverhampton is
the great storehouse whence locks are obtained. Eminent lock-makers
reside in London and in other principal towns; but Wolverhampton is
regarded by all as the centre of the trade. This is not a modern
localisation, for we have information respecting the locks of
Wolverhampton a century and a quarter ago. Among the Harleian
Manuscripts is an account of “The Voyage of Don Manuel Gonzales (late
merchant), of the City of Lisbon in Portugal, to Great Britain:
containing an Historical, Geographical, Topographical, Political, and
Ecclesiastical Account of England and Scotland; with a Curious
Collection of things particularly rare, both in Nature and Antiquity.”
This Ms. appears to have been written about 1732; it was translated
from the Portuguese, and printed in Pinkerton’s Collection of Voyages
and Travels. With reference to Wolverhampton, Gonzales says: “The chief
manufacturers of this town are locksmiths, who are reckoned the most
expert of that trade in England. They are so curious in this art, that
they can contrive a lock so that if a servant be sent into the closet
with the master-key, or their own, it will shew how many times that
servant hath gone in at any distance of time, and how many times the
lock has been shot for a whole year; some of them being made to discover
five hundred or a thousand times. We are informed also that a very fine
lock was made in this town, sold for 20_l._, which had a set of chimes
in it that would go at any hour the owner should think fit.” If Gonzales
were correct in these descriptions, they indicate an exercise of
considerable ingenuity in lock-construction, especially in reference to
the lock which keeps a registry of the number of times it has been
opened. There is abundant evidence that the old lock-makers were very
fond of these knick-knack locks, which would do all sorts of strange and
unexpected things; and this may in part account for the great favour in
which locks have been held by amateur machinists.

The lock-manufacture in South Staffordshire is of a remarkable
character, comprised as it is within so small an area. Although
Wolverhampton is known commercially as the chief depôt of the English
lock trade, yet it is at Willenhall, three or four miles eastward of
that town, that the actual manufacture is chiefly carried on. When the
Commission was appointed a few years ago to inquire into the condition
of children employed in trades and manufactures, Mr. R. H. Horne was
deputed to examine the Wolverhampton district; and his report is too
curious, and too closely connected with our present subject, to be
passed unnoticed. We here give an abstract of such parts of his report
as bear reference to the lock-makers of Willenhall.

Almost the entire industry of Willenhall is in the three articles of
currycombs, locks and keys, and articles connected incidentally with
locks, such as bolts and latches. At the time Mr. Horne wrote, in 1841,
there were among the master manufacturers 268 locksmiths, 76 key-makers,
14 bolt-makers, and 13 latch-makers; besides many small masters living
in such out-of-the-way corners that they escaped enumeration. In the
_Post-Office Directory_ of that district, of later date, there are
entries of rather a curious character. In the first place it is
observable that different kinds of locks are made by different persons,
each manufacturer confining his operations apparently to one kind of
lock; one is a _rim-lock_ maker, another a _trunk-lock_ maker, a third a
_cabinet-lock_ maker, a fourth a _padlock_ maker, a fifth a
_mortice-lock_ maker, and so on. But a much more singular feature is,
that lock-making is combined with retail dealing of a totally different
kind; thus among the occupations put down opposite the names of
individuals are, “key-stamper and beer-retailer,” “door-lock maker and
beer-retailer,” “grocer and trunk-lock maker,” “Malt-Shovel
tavern-keeper and rim-lock maker,” “lock-maker and provision-dealer,”
“grocer and key-maker,” “cabinet-lock maker and Woolpack tavern,”
“key-stamper and registrar of births, &c.,” “Hope and Anchor and
cabinet-lock maker,” “auctioneer and locksmith,” “rim-lock and varnish
maker,” and so forth. It is probable that in some of these cases the
wife attends to the retail shop, while the husband attends to the
workshop.

Among all the lock-manufacturers of the town there are scarcely half a
dozen in what may be termed a large way of business; there are many who
employ from five to fifteen pairs of hands, but the great majority are
small masters who are themselves working mechanics, and are aided by
apprentices from one to four in number, perhaps two on an average. Mr.
Horne thinks that there were not fewer than a thousand boys at work in
the town, chiefly upon locks and keys. The children and young persons
are employed at all ages, from seven up to manhood; from the earliest
age, indeed, in which they are able to hold a file. It is a
characteristic fact, where so many of the male inhabitants are employed
at the bench from such early years, that a certain distortion of figure
is observable; the right shoulder-blade becomes displaced and projects,
and the right leg crooks and bends inwards at the knee, like the letter
K,--it is the leg which is hindermost in standing at the vice. The right
hand also has frequently a marked distortion. “Almost every thing it
holds takes the position of the file. If the poor man carries a limp
lettuce or a limper mackarel from Wolverhampton market, they are never
dangled, but always held like the file. If he carry nothing, his right
hand is in just the same position.”

The hours of labour among the small masters are scarcely brought within
any system at all; for all the work is piecework, not paid for by the
day or hour; and each man works as long as he likes, or as long as his
business impels him. Some will file away from four or five in the
morning till eleven or twelve at night. In the larger shops, where there
are many hands employed, they come to work when they like, leave when
they like, and do as much work as they like when there; this freedom of
action being spread over a working-day of perhaps sixteen hours. The
masters say that the men prefer this system, or want of system, to any
thing more precise and regular. In the beginning of the week there is
often much idleness and holiday-keeping; and the Willenhall men make up
for this by a day of sixteen, eighteen, or even twenty hours’ work
towards the end of the week. In the beginning of the week, men and boys
have defined hours and definite periods for meals; but towards the end
of the week, when hurry and drive are the order of the day, they eat
their meals while at work, and bolt their victuals standing. “You see a
locksmith and his two apprentices, with a plate before each of them,
heaped up (at the best of times, when they can get such things) with
potatoes and lumps of something or other, but seldom meat, and a large
slice of bread in one hand; your attention is called off for two
minutes, and on turning round again, you see the man and boys filing at
the vice.”

In the processes as carried on at Willenhall, they are applied chiefly
to the manufacture of mortice, box, trunk, rim, cabinet, case, bright,
dead, closet, and padlocks. Except some of the parts of the brass-work,
which are _cast_, these locks are made by _forging_, _pressing_, and
_filing_. The forging is a light kind of smith’s work, aided by a light
hammer and a small pair of bellows; children and young persons are
largely employed in this process. Pressing is a kind of work by which
certain parts of the lock are pressed or stamped out. The presses are of
various sizes, but all require much strength to work them; the press has
a horizontal lever, crossing the top of a vertical screw, and there is
generally an iron weight at the end of each arm or half of the lever to
increase the power; one of the lever arms is grasped in the right hand
of the presser, and whirled round with a jerk; while the fingers of the
left hand place the metal in its proper position, and remove it when it
has been stamped or pressed. There is, of course, a die or cutter
attached to the press, to cut the metal in the proper form. Sometimes
the press has only one arm to the lever, and no weight at the end of
this, so that the labour of working is much increased. Children and
youths are employed at this process, so far as their strength will
admit. The last process, _filing_, is that by which the separate pieces
are shaped and smoothed for adjustment in their proper places; here
children and youths are almost exclusively employed; they stand upon
blocks so as to be able to reach the vice, and then work away with the
file, unrelieved by any change in the nature of the process.

In key-making the processes may be said to comprise _forging_,
_stamping_, _piercing_, and _filing_. The forging differs very little
from that required in making the pieces for a lock. The stamping is
effected by placing the end of an iron wire, taken red-hot from the
forge, into one half of a key-mould made in a block or kind of anvil; a
heavy weight is then raised between an upright framework, in the grooves
of which it runs by means of a cord; the cord is drawn by both hands,
with the assistance of one foot in a stirrup attached to the end of the
cord; at the bottom of the weight thus raised is the other half of the
key-mould. Such being the nature of the stamping apparatus, the process
is thus conducted: the foot in the stirrup being suddenly raised, and
the cord loosed, the weight falls upon the red-hot wire, and the blow
stamps it into the two moulds or half-moulds, which are brought
accurately together by means of the slides or side-grooves in the
framework. The rough key is also trimmed and cleared by the pressing
apparatus; that is, the surplus metal all round is cut off by a single
blow; and the metal which fills up the ring or handle of the key is cut
or pressed out in the same way. This is a heavy part of the key-work,
for which the labour of men rather than that of boys is required. The
process of _piercing_ the key consists in making the pipe or barrel,
required for most keys, except those which are intended to open a lock
for both sides; the pipe is drilled by a small machine worked with the
foot like a lathe; it is a process requiring more skill than strength,
relatively to other parts of the manufacture. The _filing_ of a key is
important; for not only is the whole key made bright, but the wards are
cut by the file and chisel. Boys and youths are employed in filing the
common keys; but those of better quality are entrusted to men.

The apprenticeship system is carried on to a remarkable extent among the
lock and key makers of Willenhall. The small masters take apprentices at
any age at which they can work. Some of them employ only apprentices,
never paying wages for journeymen, but always taking on a new apprentice
as soon as a former one is out of his time. The boys are mostly procured
from other towns, and they bring with them a small apprenticeship-fee
and a suit or two of clothes. They are bound to the masters by legal
indenture or contract; and the masters board and lodge and clothe them
during their apprenticeship. One consequence of this system is, that
when the apprentice has served his time, he is almost driven to become a
small master himself from want of employment as a journeyman; and he
then takes apprentices as his master did before him. This accounts for
the fact that in Willenhall there are few large manufacturers and few
journeymen; while there is a constantly-increasing number of small
masters and of apprentices.

The Willenhall makers nearly all look to the Wolverhampton factors or
dealers for a market for their wares--so far at least as concerns locks
and keys; there are some other articles which they sell more frequently
to Birmingham houses. The master and an apprentice, or perhaps two,
generally trudge off to Wolverhampton on a Saturday, bearing the stock
of locks which he may have to sell; and the money receipts for the locks
or keys sold are usually in part spent at the large market of
Wolverhampton previous to the homeward journey. The Willenhall men take
contracts at so low a price as to prevent the competition of other
places; it is stated, that whatever be prices elsewhere, nothing can
come below the Willenhall prices for cheap locks. The men work hard for
small returns, and yet they have a strong yearning for their own town. A
Willenhall girl will seldom marry except to a townsman; and thus they
intermarry to an extent which maintains their characteristics as a
peculiar community. As an example of their disinclination to leave their
own town, Mr. Horne states the following circumstance: “Some years ago a
factor, who had projected a manufactory in Brussels, engaged some
five-and-twenty Willenhall men, whom he was at the expense of taking
over. He gave them all work, and from hard-earned wages of from 9_s._ to
15_s._ a-week, these ‘practised hands’ found themselves able to earn
3_l._ a-week and upwards. But they were not satisfied, and began to feel
uncomfortable; first one left, and returned home; then another; then one
or two; till, in the course of a few weeks, every man had returned to
Willenhall”--there to work harder and earn less.

It is just possible that the application of the factory system to
lock-making may first become important by making the _best_ locks
cheaper than they can be made by the handicraft method; for there seems
not much probability, at least for a great length of time to come, that
any new system will be able to compete with Willenhall in the common
locks--those of which more thousands are sold than there are tens of the
better locks. In this, however, it would not do to predict rashly.
Hand-loom weaving is cheap enough, unfortunately for those who practise
it; but yet the factory system comes down as low as the lowest hand-loom
weaving.

The editor of Hebert’s _Encyclopædia_, after noticing the facilities for
opening most locks by copying the key, makes the following announcement:
“It affords the editor of this work much satisfaction to state, that he
has in his possession a lock, the key of which _cannot be copied_, a
locksmith possessing no tools by which an exactly similar one can be
made; the machine by which the original one was made is so arranged as
to be deprived of the power of producing another like it. The lock is
very simple, very strong, and can be very cheaply made. The cost of a
complete machine to make them would be about 100_l._; with that they
might be manufactured at one-half the expense of any patent lock. The
inventor is desirous to have the subject brought before the public under
a patent; but want of time to devote himself to such an object at
present obliges him to lay it aside.” The invention not being patented,
the editor of course gave no diagram or engraving of the lock or
machine; nor does there appear to have been a patent obtained during the
sixteen or eighteen years which have elapsed since the above notice was
published. There are, however, mechanical principles sufficiently well
known to lead to a belief that such a machine is practicable; a
ticket-printing or numbering machine will, in printing 100,000 tickets,
produce such variations that no two impressions shall be identical; and
a key-making machine might, after fashioning a particular part of each
key, modify the arrangement of certain wheels and pinions so far as to
produce a slightly different result when the next key is to be operated
on.

In the manufacture of locks and keys generally, there is no reason why
the factory system should not, to a certain extent, be applicable. By
this will be understood, the production of similar parts by tools or
machines, graduated in respect to each other with more care than can be
done by the hand method. If we suppose that a lock of particular
construction comprises twenty screws and small pieces of metal, and that
there are required, for general disposal in the market, five sizes of
such a lock; there would thus be a hundred pieces of metal required for
the series, each one differing, either in shape or size, from every one
of the others. Now, on the factory or manufacturing system, as compared
with the handicraft system, forging, drawing, casting, stamping, and
punching, would supersede much of the filing; the drilling machine would
supersede the drill-stock and bow, and other machines would supersede
other hand-worked tools. This would be done--not merely because the work
could be accomplished more quickly or more cheaply--but because an
accuracy of adjustment would be attained, such as no hand-work could
equal, unless it be such special work as would command a high rate of
payment. For any one size in the series, and any one piece of metal in
each size of lock, a standard would be obtained which could be copied to
any extent, and all the copies would be like each other. To pursue our
illustration, the manufacturer might have a hundred boxes or drawers,
and might supply each with a hundred copies of the particular piece of
metal to which it is appropriated, all so exactly alike that any one
copy might be taken as well as any other. Ten pieces, one from each of
ten of these boxes, would together form a lock; ten, one from each of
another ten boxes, would form a second lock, and so on; and there would
be, in the whole of the boxes, materials for a thousand locks of one
construction, a hundred of each size.

Now the advantage of the machine or factory mode of producing such
articles is this, that they can be made in large numbers at one time,
whenever the steam-engine is at work; and that when so made, the pieces
are shaped so exactly alike, the screws have threads so identical, and
the holes are bored so equal in diameter, that any one of a hundred
copies would act precisely like all the others, thereby giving great
advantages to the men employed in putting the lock together.

These principles are being applied by Messrs. Hobbs and Co. in their
London establishment. A number of machines, worked by steam-power, are
employed in shaping the several pieces of metal contained in a lock; and
all the several pieces are deposited in labelled compartments, one to
each kind of piece. The machines are employed--in some cases to do
coarse work, which they can accomplish more quickly than it can be done
by men; and in other cases to do delicate work, which they can
accomplish more accurately than men; but so far is this from converting
the men into lowly-paid automatons (as some might suppose), that the
manufacturers are better able to pay good wages for the handicraft
labour necessary in putting the locks together, than for forming the
separate parts by hand; just as the “watchmaker,” as he is called, who
puts the separate parts of the watch together, is a better-paid mechanic
than the man who is engaged in fabricating any particular parts of the
watch.

It may be observed that the system of manufacturing on a large scale, by
many men engaged in one large building, is more nearly universal in the
United States than in England. The workshop system, as pursued at
Willenhall by the lock-makers, is very little practised in America.
Being comparatively a new community, and being at liberty to select for
imitation or for improvement whichever of the usages or systems in the
old country they may prefer, the Americans have preferred to adopt the
factory system rather than the workshop system, and to carry out the
former to an extent not yet equalled in England--not yet equalled, we
mean, in the number of trades to which it is applied.




CHAPTER XII.

ENGLISH PATENTS FOR LOCKS--AUBIN’S LOCK TROPHY.


We propose to conclude this small work with a few details respecting the
various patented inventions in locks, and concerning Mr. Aubin’s
remarkable lock trophy. These two subjects relate to locks in general,
rather than to any specified constructions in particular, and can on
that account more conveniently be given here than in connexion with any
of the foregoing chapters.

Mr. Chubb, in the appendix to his paper on locks and keys read before
the Institution of Civil Engineers, gave a useful list of all the
patents taken out in England in relation to this subject, down to the
year 1849. We here transcribe this list:

_List of Patents for Locks and Latches granted since the Establishment
of the Patent Laws._

“As no complete list of the patents granted for locks from the time of
James I. has hitherto been published, it is believed that the following
list, which has been very carefully drawn up, and which comprises all
patents from the year 1774, when the first patent for a lock was
granted, to the present time, will be found useful as a reference for
all who are interested in the subject.

  1774|May       27|Black, George, Berwick-on-Tweed.
   „  |„          „|Barron, Robert, London.
  1778|May       29|Martin, Joshua Lover, Fleet-street, London.
  1779|May       28|Henry, Solomon, Swithin’s-lane, London.
  1780|March      4|Campion, J. Newcastle-court, Strand, London.
  1782|January   18|Hutchinson, Samuel, Marylebone, London.
  1784|„           |Bramah, Joseph, Piccadilly, London.
  1789|July       7|Cornthwaite, Thomas, Kendal, Westmoreland.
  1790|February  23|Rowntree, Thomas, Surrey-street, Blackfriars,
      |            |London.
   „  |October   29|Bird, Moses, Wardour-street, London.
  1791|July      19|Ferryman, Rev. Robert, Gloucester.
   „  |November   3|Antis, John, Fulneck, near Leeds.
  1797|November  18|Langton, Daniel.
  1798|May        3|Bramah, Joseph.
   „  |December   8|Turner, Thomas.
  1799|April     11|Davis, George.
  1801|February  10|Scott, Richard, Lieut.-Colonel.
   „  |June      24|Holemberg, Samuel, London.
   „  |...         |Roux, Albert, Switzerland.
  1805|May       18|Stansbury, Abraham Ogier, New York.
   „  |December  29|Thompson, William, Birmingham.
  1815|March      7|Mitchell, William, Glasgow; and Lawton, John,
      |            |London.
  1816|May       14|Ruxton, Thomas, Esq., Dublin.
  1817|February   8|Clark, William, Esq., Bath.
  1818|February   3|Chubb, Jeremiah, Portsea.
  1819|October   18|Strutt, Anthony Radford, Mackeney.
  1820|April     11|Jennings, Henry Constantine, Esq., Middlesex.
   „  |December  14|Mallett, William, Dublin.
  1823|July      10|Fairbanks, Stephen, Middlesex.
   „  |November  13|Ward, John, Middlesex.
  1824|June      15|Chubb, Charles, Portsea.
  1825|May       14|Young, John, Wolverhampton.
  1828|May       17|Chubb, Charles, London.
  1829|June       1|Gottlieb, Andrew, Middlesex.
  1830|January   18|Carpenter, James, and Young, John, Wolverhampton.
   „  |January   26|Arnold, John, Sheffield.
  1831|April     14|Rutherford, William, Jedburgh, N.B.
   „  |May       23|Barnard, George, Bristol.
   „  |July      27|Young, John, Wolverhampton.
  1832|December  20|Parsons, Thomas, London.
  1833|December   3|Parsons, T., Newport, Salop.
   „  |December  20|Chubb, Charles, London; and Hunter, E.,
      |            |Wolverhampton.
  1834|September  6|Longfield, William, Otley.
   „  |October   11|Audley, Lord Baron Stafford.
  1835|March     18|Hill, R., Birmingham.
   „  |December  16|Warwick, J., London.
  1836|February  10|Fenton, Rev. S., Pembroke.
  1838|June      30|Uzielli, M., London.
   „  |November  13|Thompson, S., London.
  1839|February  21|Uzielli, M., London.
   „  |June      12|Sanders, J. Stafford.
   „  |July       3|Cochrane, A., Strand, London.
   „  |July      20|Schwieso, J. C., London.
   „  |August     1|Williams, W. M., London.
   „  |December   2|Guest, J., jun., Birmingham.
  1840|February  27|Williams, W. M., London.
   „  |March     20|Gerish, F. W.
   „  |May        2|Pearse, W., Hoxton, Middlesex.
   „  |June      13|Wolverson, J., and Rawlett, W., Stafford.
   „  |October   22|Clark, T.
   „  |December  23|Baillie, B., London.
  1841|March     29|Tildesley and Sanders, Willenhall and Wolverhampton.
  1841|May        6|Hancock, James, Sidney-square, Mile End.
   „  |July      14|Berry, Miles, Chancery-lane.
   „  |September 28|Strong, Theodore Frederick, Goswell-road.
   „  |November   9|Smith, Jesse, Wolverhampton.
  1842|January   15|Poole, Moses, Lincoln’s-inn.
   „  |May       24|Duce, Joseph, Wolverhampton.
   „  |June       1|Williams, W. M., 163 Fenchurch-street.
   „  |December  29|Rock, Joseph, jun., Birmingham.
  1843|November  25|Tann, E. E. and J., Hackney-road.
   „  |„          „|Rock, Joseph, jun., Birmingham.
  1844|July      30|Fletcher, Rev. William, Moreton House, Buckingham.
  1845|April     15|Carter, George, Willenhall.
   „  |July      12|Ratcliff, Edmund, Birmingham.
   „  |December   4|Poole, Moses, Lincoln’s-inn.
   „  |December  22|Smith, Philip, High-street, Lambeth.
  1846|July       6|De la Fons, John Palmer, Carleton-hill, St. John’s
      |            |Wood.
   „  |July      15|Thomas, William, Cheapside.
   „  |December  14|Chubb, John, St. Paul’s Churchyard.
  1847|January   11|Chubb, John, and Hunter, Ebenezer, sen., St. Paul’s
      |            |Churchyard.
   „  |April     15|Collett, Charles Minors, 62 Chancery-lane.
  1848|September 28|Newall, Robert Stirling, Gateshead.
  1849|May        8|Wilkes, Samuel, Wednesbury-heath, Wolverhampton.

Mr. Chubb also gave a list of such papers m the Transactions of the
Society of Arts as refer to locks and keys.

_List of References to the “Transactions of the Society of Arts,” on the
subject of Locks._

  vol. page.
   1.   317  Mr. Moore.
   2.   187   „  Cornthwaite.
   3.   160  Marquis of Worcester.
   „    165  Mr. Taylor.
   „    163   „  Marshall.
  18.   239   „  T. Arkwright.
   „    243   „  Bullock.
  19.   290   „  W. Bullock.
  36.   111   „  M. Somerford.
  38.   111   „  A. Ainger.
   „    205   „  Bramah.
  42.   125   „  J. Duce.
  43.   114   „  W. Friend.
  45.   123   „  Machin.
  48.   132   „  S. Mordan.
  50.    86   „  A. Mackinnon.
  51.   128   „  J. Meighan.

Among the most curious mechanical productions in the Great Exhibition of
1851, was one which attracted very little notice, viz. that forwarded by
Mr. C. Aubin of Wolverhampton. Whether it was that attention, so far as
regards locks, was too much absorbed by the “lock controversy,” or
whether there was a deficiency of descriptive cataloguing, no juror or
newspaper critic, as far as we are aware, took notice of the production
in question. In the _Official Illustrated Catalogue_ it is entered
simply as “Specimens to illustrate the rise and progress of the art of
making locks, containing forty-four different movements by the most
celebrated inventors in the lock trade.” This trophy of lock ingenuity
(for such it may be justly considered to be) is now in the possession of
Mr. Hobbs. Springing from a hexagonal base-piece is a central axis,
about three feet in height, supporting four horizontal circular discs,
placed at different parts of its height. Each of the vertical faces of
the base-piece contains a lock, which is worked by its respective key.
Each disc contains a number of locks: 16 on the lowest, 12 on the next
above, 9 on the third in height, while a Bramah lock surmounts the
whole. All the locks on the discs are so arranged that their bolts shoot
outwards, or radially away from the axis of the machine. Every lock has
its own proper key inserted in the key-hole; and as the locks lie down
horizontally, the shaft of each key is of course vertical. There are
delicate pieces of mechanism contained within the central axis and
within the discs, consisting of levers, racks, and pinions; and the
Bramah lock is contrived so ingeniously, that the Bramah key, by acting
upon that lock, acts upon all this mechanism. The Bramah barrel, in
rotating horizontally under the action of its key, gives a rotary
movement to a rod passing vertically through the centre of the whole
apparatus; this rod, at the levels of the several discs, acts upon racks
and pinions, and these in turn act upon the key-pins of the several
locks. When, therefore, the Bramah key is turned, the whole of these
key-pins rotate, each exactly in the same way as if the lock were being
closed or opened, and the bolts shoot in or out accordingly. The Bramah
key, although it acts as a master-key, is not such as usually obtains
that designation; it is simply a means of putting in action certain
rack-and-pinion mechanism, which does not belong to lock-work considered
_per se_. All the locks are faithful representatives of the several
patents or modes of construction to which they severally refer; and each
exhibits the works sufficiently open to display the principle on which
it is arranged. Each lock is numbered, and is referred to in an
accompanying description. The works are finished with the utmost care
and polish; and the trophy being somewhat tastefully arranged, and kept
under a glass shade, forms a really elegant specimen of mechanical
skill.

For an account of the locks themselves which constitute this trophy, we
cannot do better than avail ourselves of the description given in the
article “Lock” in Tomlinson’s _Cyclopædia of Useful Arts_, adding a few
further details in respect to some of the locks of the series. The locks
are arranged and numbered according to their similarity of construction;
and it is instructive to remark the evidence here afforded, that many
patentees would have saved much time and money if they had better known
the productions of their predecessors. In describing these locks we
shall do so briefly, sufficient to shew their relative principles of
construction; many of them having been described more or less fully in
former chapters.

No. 1 on the list is called a _Roman lock_; it consists of a single
bolt, with a binder-spring for holding the bolt in any position in which
it may be placed until a sufficient force is applied to overcome it: it
embodies the simple principle on which thousands of common locks are
annually made.

No. 2, called a _French lock_ (all such designations are of rather
doubtful correctness), resembling No. 1 in every thing except having the
addition of a friction-roller. The bolt of either of these two locks can
easily be forced back by pressing on the end.

No. 3 is marked _Ancient_; it is a bolt-lock, and was found in an
ancient building. It exhibits an improvement on both the former
specimens, in so far as the bolt requires, before it can be shot, to be
pressed down, in order to release it from a catch at the back end of the
bolt; this release cannot be effected without the aid of a key or some
other implement applied through the key-hole, and thus the bolt answers
the purpose both of bolt and tumbler.

No. 4, also marked _Ancient_, is in principle a single-acting
tumbler-lock; that is, one in which the tumbler may fail to be lifted
high enough, but cannot be raised too high, to release the bolt: whereas
a double-acting tumbler, being susceptible both of too much and too
little ascent, must be raised to one definite and precise height to
attain the required object.

No. 5, an _old English lock_, exhibits a great advance in principle,
being provided with the double action just described as being wanting in
No. 4.

No. 6, _modern English_ (no maker’s name), is a single-acting
tumbler-lock.

No. 7, by _Mace_, is a double-acting tumbler, but without exhibiting any
peculiarities of construction.

No. 8 is _Somerford’s first patent_. It is a double-acting _draw_
tumbler-lock; that is, there is a tumbler which is drawn down instead of
being lifted, as in most locks.

No. 9, designated, we know not on what grounds, an _Indian_ lock, has a
single-acting tumbler with a pin.

No. 10, patented by Thompson in 1805. In this lock there are two
tumblers, one of which is single and the other double-acting.

Next follow a considerable number of locks, which differ one from
another too slightly to render any formal description necessary. No. 11,
by _Daniells_, is a single-acting tumbler, differing only in form from
those previously used. No. 12 is by _Walton_. No. 13 is _Barron’s_ first
patent, taken out in 1774. No. 14 is by _Bickerton_. No. 15 is a _Dutch_
lock. No. 16 is by _Duce_, senior. No. 17, by _Sanders_, is a lock with
four double-acting tumblers. No. 18, patented by _Cornthwaite_ in 1789,
is so nearly like Sanders’s, brought before public notice in 1839, as to
corroborate what we have said concerning the identity, or at least close
resemblance, of inventions widely asunder in point of time. No. 19 is by
_Richards and Peers_.

No. 20 is _Somerford’s_ second patent; a lock which seems to embody the
principle of Mr. Tann’s “reliance-wards,” patented many years later. No.
21 is _Rowntree’s_ lock, patented in 1790. No. 22 is the first patent
lock of _Duce_, junior, dated 1823. No. 23 is _Parsons’_ first patent,
of 1832. No. 24 is _Bickerton’s_ second. No. 25, patented by _Price_ in
1774; this, so far as at present appears, was the first lock ever
constructed with four double-acting tumblers, bearing a closer
resemblance than would generally be supposed to those patented by other
persons in more recent years. No. 26 exhibits a somewhat similar
coincidence. It was introduced by Aubin in 1830, and is furnished with a
_revolving curtain_ for the purpose of closing the key-hole during the
revolution of the key. Other inventors have since then adopted the
revolving curtain; and in a patent taken out so recently as 1852, this
appendage is claimed as part of the patent.

No. 27 is _Barron’s_ second patent, dated 1778; a lock which has perhaps
been the model for a larger manufacture of plain simple tumbler-locks
than any other. No. 28 is by _Bird_, 1790. No. 29 is the second patent
of _Duce_, junior. No. 30 is _Ruxton’s_, 1818. No. 31 is _Chubb’s_
simplified lock, 1834. No. 32 is by _Marr_. No. 33, by _Tann_, is the
“reliance-ward” lock adverted to above as having been anticipated, in
respect to its leading principle, by _Somerford’s_ second patent. No. 34
is by _Hunter_, 1833. No. 35 is _Parsons’_ second patent, of the same
year. No. 36 is by _Lang_, 1830. No. 37 is _Lawton’s_, dated 1815. No.
38, patented by _Strutt_ in 1839, has an arrangement for holding the
tumblers, in the event of a pressure being applied to the bolt; an
arrangement bearing a considerable resemblance to one recently adopted
in Chubb’s bankers’ lock. No. 39 is by _Scott_, 1815. No. 40, _Chubb’s_
patent of 1818, is the original detector-lock of this maker. Most of the
detectors since patented by various persons are little other than
variations of Chubb’s original.

No. 41, _Parsons’_ third patent of 1833, is a _changeable_ lock of
peculiar construction. The elevation of the tumblers is regulated by an
adjusting-screw passing through the lock to the inside of the door; this
screw changes the positive but not the relative positions of the
tumblers; so that the same difference in the steps of the key must be
retained, the change being made only in the length of the bit: the
number of changes for each lock is very limited.

No. 42, invented by _Pierce_ in 1840, seems to be a carrying out of the
plan suggested by the Marquis of Worcester in his _Century of
Inventions_, where he says that “a lock may be so constructed that if a
stranger attempteth to open it, it catches his hand as a trap catcheth a
fox; though far from maiming him for life, yet marketh him so, that if
once suspected he might easily be detected.” In Pierce’s lock a steel
barb or sharp arrow-head is concealed below the key-hole, in such a
manner that if any person in attempting to open the lock should
over-lift the tumbler, the barb would be thrust by a spring into his
hand. It is said that the patentee himself experienced the efficacy of
this invention, by receiving the barb into his own hand.

No. 43, by _Ruxton_, patented in 1816, is furnished with a tell-tale, so
arranged that if the tumbler be over-lifted in an attempt to pick the
lock, a pin or catch is thrown out from the lock, which would be visible
on opening the lock with the proper key. This invention preceded Chubb’s
detector by two years, and would be entitled to some of the honours of
originality were not Chubb’s arrangement much more simple and effective.

No. 44 is _Bramah’s_, the patent of 1784, and the crowning lock of the
trophy, by which all the others are opened. Similar locks by _Russell_
and _Mordan_ are applications of the Bramah principle, with little or no
variation.

       *       *       *       *       *

No attempt has been made in these pages to describe every variety of
lock that has been introduced. Several forms of puzzle locks, known as
_Russian_ and _Chinese locks_, have the forms of various animals, and
they are locked and unlocked by pressing upon or moving some portion of
the body of the animal: the security of such locks depends in many cases
upon keeping the part to be pressed or moved secret. There are also
various forms of alarum locks; but these do not greatly differ from
common locks, except in having certain appendages, such as a pistol,
which if loaded and properly adjusted, will be fired on any attempt
being made to open the lock, either with its own key or some other
instrument. Some locks are furnished with a bell or a rattle, which is
rung or sprung on attempting to open the lock, and in this way the
inmates of the house are informed of the attempt to effect an entrance.
It will, however, be evident to any one who has read the preceding
pages, that devices of this kind do not add to the security of the lock;
they rather tend to degrade the art of the locksmith to that of the
toyman. The locksmith, in common with every other artist, can only
improve in his art by studying the principles upon which it rests, and
illustrating them by the most approved examples which the constructive
genius of his predecessors or contemporaries has furnished.




APPENDIX.


CHAPTER XIII.

ON AN IMPROVED CONSTRUCTION OF LOCK AND KEY.[12]

  [12] By J. Beverley Fenby, Mechanical Engineer, of Birmingham.
  Extracted chiefly from the Proceedings of the Institution of
  Mechanical Engineers, 1866.

The simple _fixed-guard_ or _warded_ lock is so utterly worthless for
security, no matter what amount of good workmanship be bestowed upon it,
that it demands but short notice. It was contrived with the intention of
making the passage to the bolt intricate; but it will be seen at once
that this intricacy does not really offer any security. The wards of a
lock are circular arcs of thin metal, so arranged as to require a key of
peculiar pattern to pass amongst them, the shape of the cuts in the key
being a section of the wards. To make a really complicated box of wards,
and to cut keys which shall accurately fit their sweep, is a matter
requiring considerable manual dexterity; and some warded locks are
therefore expensive. But even with the best of them, all that it is
necessary to do for opening the lock is to take a blank key which will
properly fit the keyhole, coat it with wax, and then inserting it in the
lock, press it round against the wards, which will cause them to leave
an accurate impression of their section on the key. The parts impressed
are then cut out with small files, drills, and saws, and the occasional
use of fine cross-cut chisels. The key will then pass those wards which
impressed themselves upon it; and if these are the only wards, it will
go completely round and open the lock. If there are also other wards in
addition, not brought up flush with the first wards, the key is waxed
again and pressed against them, and then further cut out, as before.
This process is evidently one of absolute certainty, and the key so made
is in all respects as capable of mastering the lock as the original key.

These warded locks are however easily opened with merely a piece of bent
steel wire,--bent into such a sweep as will reach right round the wards
instead of passing amongst them, thus escaping all chance of being
obstructed by them. Such an instrument is called by burglars a “twirl.”

The fixed-guard or warded lock was the one in general use in the middle
ages.

The next kind of lock is the _tumbler_ lock, in which the bolt is moved
backwards and forwards by the key as usual, but these movements cannot
take place till a small lever with a stump on one side be lifted. This
lever and stump form the tumbler, which is held down by a spring; and in
the tail of the bolt are two notches, into one of which the stump fits
when the bolt is shot, and into the other when it is withdrawn. All that
is necessary to effect the picking of this lock is to lift the tumbler
high enough for clearing the stump out of the notch, and then draw back
the bolt. The tumbler may be lifted with one pick, and the bolt drawn
back with another; but generally one pick will suffice for both
purposes.

In the Barron tumbler lock the principle of double-action was
introduced.

The next improvement was the _lever_ lock properly so called, under
which designation the majority of the modern locks may be classed.

The Bramah lock was an admirable contrivance with remarkably beautiful
mechanism contained in a small compass; and since its invention there
have been several ingenious modifications of the same principle in
different radial locks, such as the Yale lock, in which the slides move
radially instead of axially. One advantage in these radial locks is the
greater difficulty in copying the keys, in comparison with the flat keys
of ordinary lever locks: this difficulty however is not an
insurmountable one.

A very ingenious addition was made to the action of the lever lock in
Newell’s American lock, which was shown in the 1851 Exhibition, and
described at page 89 of the present volume.

Though locks such as those already referred to exhibit great
dissimilarity of construction, yet there is one point in which they all
agree, and that is in the possession of a direct passage from the
outside to the works. Although various locks have been devised with the
object of having no direct passage to the works from the outside, one
consideration shows the inevitable existence of such a passage; namely,
that without it the key could not possibly at one and the same time
touch the hand of the operator and the works of the lock. It therefore
follows that any instrument which can pass in the same space as the key
may be brought to bear on the works, whatever may be their construction.

It can now be shown that, if picking instruments are thus brought to
bear on the works through the keyhole, there is a regular tentative
system whereby the picking of any lock with an open keyhole can sooner
or later be effected.

From the foregoing observations it is evident that there are two
important defects in the principle of the previous lever locks, which
being defects in principle are fatal to their security; namely, the
means of access to the works of the lock through the keyhole, allowing
of a series of attempts being made to open the lock by picking
instruments; and also the facility afforded for repeating the trial of a
false key made from a wax impression of the true key, and thus
perfecting it by successive alterations after trial. In consequence of
the possibility thus allowed of making these successive attempts either
by picking instruments or by a false key, it has been shown by the
cases that have occurred of locks of the best makes which have been
falsely opened, that, however numerous and complicated may be the
secondary impediments introduced into these locks, there can be no real
security against the ultimate success of sufficiently numerous and
persevering attempts, except by the adoption of some new principle of
construction specially meeting the above two defects.

[Illustration: fig. 53.]

In the invention of the Improved Lock and Key now to be described, and
which has been termed the _adytic_ lock,[13] the writer’s object has
been to meet this requirement. In fig. 53 is shown an elevation of this
lock, such as is made for an iron safe; two of the front cover plates
being removed to show the construction.

  [13] From the Greek αδυτος, _inaccessible_.

The head B of the main bolt is of such a thickness as to be flush with
the face of the levers L and guard A; and the strap or tail D of the
bolt is thin, and passes behind the levers and guard, and also behind
the plate H H. The part of the tail D which would lie under the levers L
and cylinder C is removed, as seen in fig. 54, and replaced by a
separate flat plate or stump-bolt, carrying the stump S. This stump-bolt
has a projection K upon it, let into a recess in the tail D of the main
bolt, but with ¹⁄₁₀th inch vertical play in the recess. A spring in the
tail of the main bolt presses the stump-bolt downwards, keeping the
stump S in the notches of the levers L, as shown in fig. 53. The
stump-bolt can thus descend ¹⁄₁₀th inch at first without moving the main
bolt, and this amount of vertical movement is sufficient to carry the
stump in and out of the notches in the levers; but the stump-bolt cannot
descend further without taking the main bolt with it.

[Illustration: fig. 54.]

[Illustration: fig. 55.]

Immediately in front of the bolts comes the fixed plate H H, in which is
cut the cam groove shown by the dotted line J J; and also the vertical
slot E for the pin P to work through, together with another vertical
slot in which the stump S fits and works. This plate carries the centre
pin U on which the levers L turn. The levers are six in number, though
any other number may be used; and they occupy collectively ³⁄₈ths inch
thickness. In front of the plate H is fixed the guard A, which is made
of iron or steel, and has the brass cylinder C ground into it. The guard
is made a shade thicker than the levers L, in order to prevent the back
plate H and the corresponding front plate from being so tightened on the
levers as to impede their freedom of movement. The cylinder C is the
same thickness as the levers, excepting the centre boss F, which
projects from the back of the cylinder and works in a bearing in the
back plate H, and also projects in front through the thickness of the
two front cover plates. The small keyhole in the centre of the boss goes
only a short distance into the cylinder C, being merely for the purpose
of enabling the stem of the key M, fig. 55, to turn the cylinder; the
bit of the key is a separate piece, N, fig. 57, which is inserted
through a separate keyhole into the radial slot of the revolving
cylinder C, as shown at N in fig. 53.

This radial slot is cut in the side of the cylinder C that is furthest
from the levers when the cylinder is in the position shown in fig. 53;
and in the slot fits the slide block R, which is a steel block having a
pin projecting on each side. The back pin enters the guide groove J J in
the back plate H, as shown by the dotted line, and the front pin enters
the corresponding guide groove in the front cover plate, which is shown
removed. The back pin of the slide block projects through the back plate
H, as shown in fig. 56, and works in the cam groove O in the tail of the
stump-bolt S, fig. 54, which is so shaped that as the slide block
travels round the guide groove J J, shown by the dotted lines, it moves
the stump-bolt vertically as may be required according to the position
of the bolts and levers.

[Illustration: fig. 56.]

In the position of the lock shown in fig. 53, the bit N has been
inserted into the vacant space of the radial slot in the cylinder C, in
front of the slide block R. The size of this vacant space is ³⁄₈ths inch
long by ¹⁄₈th inch wide and ³⁄₈ths inch deep; and in the two front cover
plates of the lock, and also in the door to which the lock is attached,
a hole is made of the same shape. In the door there is no bearing for
the centre boss F, but only a small keyhole corresponding in size with
that in the boss F for inserting the stem of the key.

       *       *       *       *       *

In the position of the parts shown in fig. 53, it will be seen that the
levers L are held pressing down against the circumference of the
cylinder C by their springs I bearing against the pin P. In this
position also the bolt spring between the main bolt and the stump-bolt,
fig. 54, presses the stump S down into the notches of the levers, so
that the levers are completely locked by the stump, as seen in fig. 53.

In order to unlock the lock, which in fig. 53 is shown with the bolt
shot, it is necessary that all the gatings G in the levers should be
brought precisely under the stump S. Through the centre keyhole F there
is no communication possible at any time with the levers L; nor will any
instrument, however slender, if passed into the radial slot through the
aperture at N be able to reach them, whether the cylinder C be in the
position shown in fig. 53 or turned round into any other position. For
the only difference made by turning the solid cylinder C is that the
radial slot in it is carried away from the aperture in the external
plates, and the solid part of the cylinder is brought opposite to the
aperture, which is thereby completely closed against the insertion of a
picking instrument. This construction accordingly not only precludes the
possibility of opening this lock with an ordinary key, in which the part
that acts on the levers is attached to the stem of the key, but it also
renders it an absolute impossibility to introduce a pick of any form, as
nothing can reach the levers L except a detached piece of such a size
and shape as to be capable of travelling round in the vacant space left
in front of the slide block R in the radial slot of the cylinder C.

[Illustration: fig. 57.]

For the purpose of unlocking the lock the bit N, fig. 57, is used. This
bit is of such a size as to fit into the vacant space of ³⁄₈ × ³⁄₈ × ¹⁄₈
inch in the radial slot of the cylinder C; and the indent at V is merely
for the purpose of ensuring the insertion of the bit in the right
direction, the external aperture for the bit being made with a
corresponding projection to fit the indent in the bit. This bit being
inserted through the aperture in the door, is pushed in by means of the
key stem M, which is flattened on two sides for that purpose, as shown
in fig. 55; and the bit is thus pushed home into its place in the radial
slot of the cylinder, as shown at N, fig. 53.

The key stem M is now inserted into the centre keyhole F, and the
cylinder is turned round by it in the direction shown by the arrow,
carrying round the slide block R and the bit N. The slide block R, while
moving through the concentric portion at the commencement of the guide
grooves J J, does not affect the bit; but by means of the cam groove O
in the tail of the stump-bolt, fig. 54, it moves that bolt so far as to
lift the stump S completely out of the notches in the levers L, which
are thereby left free to be raised. On continuing to turn the cylinder
C, the eccentric part of the guide grooves J J causes the slide block R
to move outwards along the radial slot, pushing the bit N before it; and
the bit is thus made to project beyond the circumference of the
cylinder, which it can then do, being no longer confined by the guard A.
The further projection of the bit as the cylinder revolves causes the
steps in the bit to lift their respective levers; and the steps in the
bit are so arranged that, when the cylinder arrives at the position
shown in fig. 58, all the gatings G are brought simultaneously opposite
the stump S, which is instantly shot down through the distance of the
¹⁄₁₀th inch play by the bolt spring. The bit N remains in contact with
the extreme part T of the levers while the stump S is entering the
gatings, the action of the bolt spring being so rapid that the bit
cannot move through any appreciable distance during the time.

[Illustration: fig. 58.]

In other locks a spring action of this kind would greatly facilitate the
picking, inasmuch as it would afford the gentle uniform pressure desired
upon the levers. In other locks, therefore, the bolt is caused to move,
and the stump to enter the gatings, by the direct contact of the key
with the bolt, instead of by a spring; but as the key, while moving the
stump into the gatings, is also altering its position under the levers,
a slight tremulous motion of the levers is thereby occasioned, which no
care in manufacture can obviate. This tremulous motion is aggravated by
the circumstance that, as the keyhole is open to inspection, it is
necessary to make all the levers fit flush with one another when down,
in order to avoid affording any clue to the shape of the key from the
positions of the levers; but as the various steps of the key, being of
different lengths, describe different arcs, the curves of the levers
when raised are of necessity in error to them all. The result of these
combined faults is that the gatings have to be made wider than the
stump, to allow a sufficient amount of play, thus introducing a fatal
element of insecurity in the construction of the lock, since the
security is of course enhanced in proportion as the gatings fit the
stump accurately. In the new lock, on the contrary, the arc T, fig. 58,
in each lever, can be shaped truly to its own proper radius, independent
of all the rest of the levers; and as the action of the stump is
instantaneous in catching the gatings as soon as they are all brought
simultaneously under it, the stump and gatings can be made to fit one
another with the most perfect accuracy, and without the slightest play.

On turning the cylinder C further round, the bit N passes from under the
levers, which remain held back by the insertion of the stump in the
gatings; and just before reaching the position shown in fig. 59, the
slide block R has pushed the bit completely out of the radial slot, and
the bit falls down as shown in fig. 59, and drops through a hole into
the inside of the safe that is locked. At this point the back pin of the
slide block comes in contact with the lower side of the cam groove O in
the stump-bolt, fig. 54; and by turning the cylinder C onwards to the
position shown in fig. 60, the withdrawal of the bolt B is completed,
bringing the parts into the position shown in fig. 60. In these drawings
only one lever L is shown; but there are altogether six levers, as
shown in the sectional plan, fig. 56. The pin P is fixed in the tail D
of the main bolt, so as to travel with the bolt; and by this means the
springs I are released from strain, as shown in fig. 60, as soon as the
bolt is withdrawn.

[Illustration: fig. 59.]

       *       *       *       *       *

From the nicety with which the various parts of this lock are
constructed, it is evident that the levers must be very accurately
lifted by the bit of the key in order to withdraw the bolt; and
therefore any error in the bit, such as would occur with a false bit,
will effectually prevent the lock from being opened. This may be
illustrated by supposing the false bit to be so close an imitation as to
have five of its steps absolutely correct, and the sixth only slightly
wrong: though it is almost impossible that such a near approach to
correctness could be attained in practice. The counterfeit bit being
inserted in the lock, and the cylinder turned round, all will go on the
same as with the true bit, up to the time when the false bit reaches
the point T of the levers, as previously shown with the true bit in fig.
58. Here a change of action takes place; but what is the nature of the
change the operator has no means as yet of ascertaining. In the case
supposed, where five of the steps in the bit are right, but the sixth is
wrong, the gating of the sixth lever does not precisely coincide with
the others, nor with the stump S; and the consequence is that, at the
critical moment when the stump ought to spring into the gatings and hold
back the levers from falling forwards, it will be prevented from
entering the gatings, owing to the entrance being partly blocked up by
the one lever, which stands more or less across it.

[Illustration: fig. 60.]

The fact, however, that the stump cannot enter the gatings, does not
become known to the operator until the cylinder C has been turned
further round, so as to bring the slide-block pin in contact with the
lower side of the cam groove O in the stump-bolt; and before this point
has been reached the false bit has already passed clear of the levers,
which, not being retained by the stump, are instantly thrown forwards
again by their springs, and locked in their original position by the
stump entering the notches. At the same time the false bit has dropped
into the inside of the safe in the same manner as the true bit, as shown
in fig. 61.

[Illustration: fig. 61.]

Hence a person putting a false bit into one of these locks will not only
infallibly lose it at the very first trial, but will do so without
gaining any information as to the nature of its inaccuracy; for as the
gatings of the levers cannot be seen or felt, all that can be told about
the action of a false bit is, that it has failed to open the lock. In
fact, a counterfeit bit passes under the levers, and through the lock,
just like the true bit; and it is only the stoppage afterwards met with
of the bolt that indicates the failure of the false bit, which is by
that time gone beyond recovery. Whatever amount of labour, therefore,
may have been spent on the fabrication of a counterfeit bit, this bit
can only be tried once, so that no alteration can afterwards be made in
it.

Nothing that can be inserted into the radial slot of the cylinder C
through the aperture in the front plates can do any injury to the lock;
and a charge of gunpowder inserted in that way would only blow out
again at the orifice without damaging the lock, both the apertures for
the key being merely blind holes with parallel sides.

       *       *       *       *       *

[Illustration: fig. 62.]

[Illustration: fig. 63.]

For the manufacture of the bits for the keys of this lock a self-acting
machine is employed, in which the height and width of the several steps
in the bit are regulated by adjustments of very great accuracy, and
admitting of an almost endless variety of figure for the bits. This
key-cutting machine is shown in figs. 62 to 64, and consists of a small
circular saw A running vertically, of the same thickness as each step
in the bit I, which is brought up to the saw by the slide-rest B. The
bit I is fixed in the holder C, which rocks upon a centre, so as to give
the required curvature to the edge of each step in the bit when cut by
the saw, as shown in the full-size section of the bit-holder, fig. 63.
The adjustment of the depth of cut is effected by the set screw D upon
the slide-rest coming up against the eccentric ring E upon the bed of
the slide-rest; this ring is turned round by hand, and set to sixteen
different positions by means of the catch-pin F and the sixteen holes on
the circumference of the ring, allowing of sixteen different depths of
cut. The lateral adjustment for the pitch between the successive steps
of the bit is effected by the two bed-screws G G acting on the
slide-rest B, having a dividing plate on the head, and such a pitch of
thread that one turn of the screws traverses the slide-rest through the
exact distance of one step in the bit. The occurrence of any play or
backlash is entirely prevented by having the screws placed one at each
end of the slide-rest; so that by slacking back one screw through one or
more turns, and then advancing the other through the same number of
turns, the slide-rest is always held with perfect steadiness between
them, filling exactly the space between the ends of the two screws.

The number of changes admissible in this key-cutting machine, if used
for making keys for locks having six levers, is the number of
permutations that sixteen terms are capable of when taken six together,
which is upwards of sixteen millions. Some of these changes are so
slight that too great accuracy of workmanship would be required to make
the locks accordingly; but of those changes that differ from one another
so far that no lock could be opened by any other than its own key, more
remain than could be used up by all the locks in the world.

[Illustration: fig. 64.]

The writer may observe that it was the study of the circumstances of the
great gold robbery on the 15th of May, 1855, by Agar and his
confederates (when two of the best lever locks were picked, and gold
stolen weighing upwards of 200 lbs., while in transit on the
South-Eastern Railway from London to Paris, packed in three sealed
iron-bound boxes, inclosed in a bullion safe, secured by those locks),
and of the various modes of picking locks, which led him to turn his
attention to the achievement of what had been so long and perseveringly
sought after, namely, an unpickable lock. The principle of a detached
bit has been previously tried, in so far as that locks have been made in
which the bit of the key was deposited in the lock by unscrewing the key
stem, and then withdrawn by screwing in the stem again. But inasmuch as
the detached bit, even though it failed to open the lock in the case of
a counterfeit key, could always be brought back again to the keyhole and
removed, this admitted of a repetition of attempts with successive
alterations of the one counterfeit key, without the certainty that any
warning would be given by the lock of such attempts having been made.

In another still more complicated lock with a detached bit there were
two keyholes, into one of which the bit of the key was put, and the stem
being then unscrewed from the bit, was put into the second keyhole and
turned round so as to close the first keyhole over the bit; a separate
handle was then turned to work the lock, six separate operations being
required for either opening or closing the lock. Further, a kind of
retainer has been attempted by so arranging the lock that, if any key
was put in but the right one, it was held in the keyhole in such a
manner that it could never be got out. In this case, however, if the
false key would not open the lock, neither would it let even the right
one do so, and it would be necessary to break open the door secured by
the lock.

       *       *       *       *       *

In the new lock here described, the special points that have been aimed
at are the following:--

Firstly, in no position of the lock is there any access to the works
from the outside through the keyhole. This access through the keyhole is
more or less a defect in all other principles of lock, as it admits of
feeling and manipulating the works for the purpose of getting
information for picking the lock in the absence of the right key;
whereas in the new lock there is no opening whatever at any time, except
the two plain parallel recesses into which the key and the bit are
fitted. From the moment the turning of the lock commences both these
recesses are effectually blocked up: the one for the bit being conveyed
bodily away from the keyhole, and its place taken by the solid metal of
the cylinder; while the other is completely filled by the key, which
cannot be withdrawn except by turning it back to the original position.
In consequence of this construction no injury can be done to the lock by
explosion of gunpowder in the keyhole, the only openings from the
outside being parallel at their sides, and not communicating with any
portion of the interior of the lock; and the simplicity and solidity of
construction are such that the revolving cylinder is made practically
air-tight within its bearing. This effectually prevents all attempts to
open the lock by picklocks, and leaves no alternative but the attempt to
make a sufficiently accurate copy of the true key.

Secondly, as no clue whatever can be obtained from the outside of the
lock respecting the key required, the attempts upon the lock are thus
limited to the chance of obtaining a wax impression of the true key. The
difficulty of making a counterfeit key sufficiently correct by this
means for opening one of the best of the previous constructions of lock
is very great; but in the new lock this difficulty is greatly increased
by the fact of the levers remaining absolutely stationary while the
stump enters the gatings, in consequence of which the gatings are made
so close a fit to the stump that an exceedingly minute error in the
lifting of any of the levers is sufficient to prevent the lock being
opened. This extreme delicacy of construction can be carried out
practically without objection in the new lock, because there is no
possibility of putting a strain from the key upon the stump, so as to
cause injury by forcing it at the moment of entering the gatings; for
the only force acting upon the stump at that time is the uniform
pressure of its own spring. In addition to this source of increased
safety, there is the still more important circumstance that only a
single trial can be made of each counterfeit bit; because, if carried
forwards far enough to try its effect in opening the lock by passing the
levers, the bit is inevitably lost by falling through the lock and
inside the door. Thus not only is all chance prevented of a second trial
with the same key, but the bit retained inside the door gives warning of
the attempt having been made, and shows how near the counterfeit key has
approached to the original. The numerous cases that have occurred of
attempts to open locks by counterfeit keys, such as the remarkable
instance previously referred to, show that even with the most practised
hands it is next to impossible to make from a wax impression a key that
will serve for opening a good lock the very first time it is tried; and
the striking importance is therefore seen of this arrangement in the new
lock, which prevents more than a single attempt being made with a
counterfeit.

Thirdly, another advantage to be named in this lock is that the stem
alone of the key is required to lock it, but it can only be unlocked by
the complete key. The stem, therefore, can be left by the principal of
an establishment for locking up by a subordinate; but the bit, which is
the essential part of the key required for opening the lock, need never
be used or seen by any one but the principal himself. As the hole in the
external door-plate for the stem of the key has a notch on one side only
to admit the key stem, and the cylinder is prevented from making a
complete revolution, the stem of the key cannot be withdrawn from the
lock except when the bolt is shot; so that its absence from the keyhole
serves as a proof that the bolt is shot.

Fourthly, one other advantage in this lock is its simplicity and
solidity of construction. It contains no more parts than the simpler
forms of lever lock having the same number of levers, and the total
number of separate pieces in the complete lock is only sixteen. The
principle of security, therefore, upon which the new lock is
constructed, avoids entirely the complications and the delicate and
minute class of work rendered necessary in other locks by the use of
detectors and the other auxiliary contrivances employed for increasing
the difficulty of picking.

       *       *       *       *       *

Mr. Fenby exhibited, at a _conversazione_ of the Institute of Civil
Engineers, and at the meeting of Mechanical Engineers, specimens of his
adytic lock, and showed its action both with the true key and with
counterfeit keys; and he showed by trial that the counterfeit failed to
open the lock, notwithstanding that by means of the permutating cutting
machine it had been made a much nearer approach to a perfect copy than
was practicable in the best handwork from a wax impression. He also
exhibited the key-cutting machine employed for cutting the bits; and
also a set of burglar’s tools employed for drilling into the door of an
iron safe sufficiently for breaking open or removing the lock, showing
that the hold required for giving the cutting pressure upon the powerful
drill employed for the purpose was obtained by a steel cross piece
inserted into the keyhole and turned at right angles, so as to hold
across inside the lock; but in the new lock, as the keyhole had no
opening into the lock, and only a slight shoulder on one side, no means
were afforded for obtaining the required hold for the drill.

The following are the salient points of the discussion that followed the
reading of his paper:--

The Chairman remarked that the paper just read gave a very excellent and
clear description of the detailed working of the new lock, and he
thought this construction of lock was a most valuable one, as affording
real security against all fraudulent attempts. He inquired whether there
would be any possibility of tampering with the lock by examining it upon
the inside of a safe door, whenever the door might happen to be left
unlocked.

Mr. Fenby replied that there was no means of tampering with the lock
from the inside of the door, as the two keyholes for working the lock
were only in the front face of the door, and the lock was all closed up
on the inside of the door, excepting the hole through which the bit was
allowed to drop out; but this would be useless for the purpose of
tampering with the lock, as the bit dropped down a tube leading to the
bottom of the door, through which no examination of the lock could be
successfully made.

The Chairman inquired whether there was any provision against the bit
being accidentally locked up inside the safe, in which case it appeared
the lock could not be opened again.

Mr. Fenby replied that the owner of the safe must of course be careful
after unlocking the safe to take the bit out before locking it again,
otherwise there would be no means of opening the lock afterwards with
that key. As a precaution, however, against any such accident, each lock
was provided with three bits, all duplicates, one of which would be kept
in the pocket for use, while the two others would be preserved in a
place of safety for the chance of any such contingency. Moreover, in
most of the safes fitted with these locks, the tube through which the
bit dropped had been made of such a length as to carry out the bit on
opening the door, dropping it into a small tin tray outside the safe;
and by this means the accidental locking in of the right bit was
rendered impossible. One of the advantages of the new lock was that the
stem of the key was not required to be kept constantly in the possession
of the owner, but it might be left in the lock, as the bit alone was the
valuable part of the key; and as the bits were of such small size and
convenient shape, a number of them might readily be kept in the pocket
by a person having charge of a number of safes, without the
inconvenience attending a large bunch of ordinary keys. In the case of
an attempt being made to open the lock with a counterfeit bit, the
advantages of retaining the counterfeit inside the safe were not merely
that the person attempting the lock was deprived of his instrument,
while the proprietor immediately discovered the attempt upon the next
occasion of opening the safe; but the retention of the counterfeit
itself afforded the means of judging, by a comparison with the true bit,
whether the attempt had been made altogether in the dark as to the
actual construction of the lock, or whether it was likely that some clue
regarding the true bit had been obtained by means of a wax impression or
otherwise. In the latter case the owner of the safe might think it
desirable to have the lock taken off, and the arrangement of the levers
altered, and a new bit made so as to baffle any further attempts.

Mr. W. S. Longridge observed that the inconvenience that had been
alluded to with the new lock, of accidentally locking up the bit inside
the safe, was no greater than occurred with an ordinary safe lock if
ever the key was accidentally lost; in either case, unless the
precaution was taken of keeping a duplicate in reserve, it would of
course be necessary to have the safe broken open.

The Chairman inquired how the ideas had been arrived at of separating
the bit from the key, and of preventing all access to the works through
the keyhole, and also of retaining the bit inside the door after any
attempt at unlocking.

Mr. Fenby replied that his attention had in the first instance been
attracted to the subject of the picking of locks as a mechanical
problem, and he had found that there had hitherto been no principle in
lockmaking which could effectually baffle persevering attempts at
picking. For although there were certain complicated constructions of
locks, having many points of excellence, they had all yielded in time to
the picking instrument in clever hands; and it must be remembered that
any individual lock when once constructed remained stationary as
regarded subsequent improvement, whereas the art of picking that lock
was continually progressing towards success, with all previous
constructions of locks, and it was clear therefore that the lock must
ultimately be defeated. He had been further stimulated in the
investigation of this subject by the occurrence of the great gold
robbery referred to at page 188; and the circumstance which had struck
him most forcibly in connection with that robbery had been that locks of
the best make hitherto known had admitted of seven successive trials
being made upon them without detection, each trial furnishing the
information for further perfecting the counterfeit key, until the locks
were at length opened.

These considerations had led him to the conclusion that two points were
established and were required to be kept in view for the construction of
any lock that should be really secure against fraudulent attempts. The
first point was that wherever a man could get instruments into the lock
he could ultimately solve any problem laid before him by the maker of
the lock, as the lock when once made could be tried any number of times
if an instrument could be got into it at all. Hence he had concluded
that it was requisite for all access to the interior to be cut off, so
as to preclude all possibility of getting a pick-lock in; and this was
accordingly accomplished by adopting the plan of separating the bit from
the stem of the key. The second point established was that it was
necessary to prevent the possibility of making a succession of trials
with the same counterfeit key; and it had then struck him that, if the
bit of the key were arranged to drop inside the safe in unlocking, there
would be no means of going on gradually improving and touching up the
counterfeit from the results of previous trials, as the false bit would
be irrecoverably lost in the very first attempt, without furnishing any
clue whatever as a guide for alteration in a subsequent trial. The first
lock that he had invented for meeting the requirements thus pointed out
had been made with a solid block having a tunnel through it, but
involving the same principle of retaining the bit of the key and keeping
the levers inaccessible from the outside. Subsequently, however, he had
abandoned that construction and produced the new lock shown in the
drawings, having the revolving barrel with radial slot.

The Chairman proposed a vote of thanks to Mr. Fenby for his paper, which
was passed.


CHAPTER XIV.

FENBY’S PATENT STOP-LOCK.

This lock has been designed with a view to doing away with several weak
points in the construction of lever locks.

The introduction of the movable stump by Mr. Hobbs, in order to defeat
picking by the tentative method of applying pressure to the bolt, so as
to cause binding between the stump and the levers, was a great advance
in the art of lock-making.

The movable stump, as so constructed, was, however, open to this
objection, that while sufficiently delicate and certain in its action to
render picking very difficult, it was at the same time, through the
smallness of its parts--resulting from the confined space available for
its action--unsuited to withstand any amount of force applied to push
back the bolt.

[Illustration: fig. 65.]

In the lock under notice the stump _s_ is formed in the solid on the
shorter arm _a_¹ of a cranked lever or oscillating stop _a_. This stop
_a_ works on the steel pin or centre _b_, which latter has a bearing in
both plates of the lock. At the end _a_ of the stop _a_ is a recess
formed to fit the corner _d_ of the bolt-head. _c_ is a stud limiting
the range of _a_ in an upward direction, so that when in its normal
position the stop _a_ may just clear the bolt-head, as shown in figs.
65, 66, and 67. The tail of the bolt, instead of being in the form
usually adopted, is formed of the bar _e_ set on edge so as to reach
from the back to the front plate of the lock, completely dividing the
lower part, in which the keyhole lies, from the upper, in which the main
parts of the works are placed.

This bar _e_ works between the guide pieces _g g_, so that in whatever
position the bolt may be, the division of the lock into two chambers is
complete. At _f_ is the recess in which the key acts to move the bolt.
The levers _l_ turn upon the pin _i_ formed in the solid of the
bolt-head. The part of each lever on which the key is to act passes
through a slot or recess in _e_, the parts _h_ and _h_¹ of the levers
being struck to the arcs of circles, having their centres coincident
with that upon which the levers turn at _i_.

As it is not possible to lift the levers out of this slot in the bar
_e_, and further, as the levers and bolt move together in a longitudinal
direction, the movements necessary to locking and unlocking open no
communication between the upper and lower chambers of the lock.

The springs of the levers are formed out of the solid metal of the
levers themselves, and are thus not liable to that displacement which so
often occurs with separate springs, nor to the corrosion by oxidation
incidental to steel springs. They are cut round the corner, and down the
front of the lever, to gain greater elasticity.

In fig. 65 the lock is shown with the front plate removed, and the works
as they stand when unlocked. Fig. 66 is the same, except that the works
are shown locked, and the back plate removed instead of the front. Fig.
67 shows the _front_ view of fig. 66. Fig. 68 shows the result of any
attempt to pick the lock by pressure.

[Illustration: fig. 66.]

[Illustration: fig. 67.]

[Illustration: fig. 68.]

The lock being locked, as shown in figs. 66 and 67, it will be seen that
the stop _a_ just clears the angle _d_ of the bolt-head. Further, that
the gatings _r_ of the levers _l_ cannot pass the stump _s_, unless the
levers be so lifted as to coincide with each other and the stump. The
stop _a_ being held up by a very light pressure from the lever springs,
a small force applied to the stump _s_ is sufficient to upset its
equilibrium, and bring down its end _a_² upon the bolt-head at _d_, as
shown in fig. 68. This occurs whenever an attempt is made to “_feel_”
the stump with the levers; and not only does the stop _a_ free the
levers from all pressure, and so preserve them and the stump from
injury, and the lock from being picked, but it also forms a strut for
securing the bolt: in fact, no violence short of that necessary to shear
the pin _b_ can make the bolt yield.

The drawings show a mortise lock, but the improvements shown are
universally applicable in the construction of locks of all kinds.

For the manufacture of these and other locks, and kindred articles,
Messrs. J. B. Fenby and Co., engineers of the Liverpool Works,
Birmingham, have put up, from the designs of their managing partner, Mr.
J. Beverley Fenby, an experimental set of machinery, almost entirely
self-acting, and calculated to turn out large quantities of the
component parts of locks and other articles with extreme accuracy and
rapidity.

The whole set works on the interchangeable system--as already in use for
military small arms. It is not, however, to be supposed that, because
the parts of the locks are interchangeable, one key will open several
locks--such a source of insecurity being guarded against by the
permutating key-cutting machines invented by Mr. Fenby. These machines
give complete command over the making of keys, whether it be required to
make a comparatively unlimited number, all differing from each other, to
make a number alike, or to make sets with master keys.

Atmospheric and hydraulic pressure also plays an important part in
shaping many of the parts of the locks.


NOTE UPON IRON SAFES.

At the conclusion of this work upon locks it will not be out of place to
make a few remarks upon the degree of real safety that attaches to what
are commonly called “safes,” and to point out in a common-sense way what
are the chief dangers that these may incur from depredators (whether
burglars or in times of public anarchy and violence), and what are the
main conditions to be relied upon for safety--assuming that, by one or
other of the constructions pointed out in the preceding pages, the
_lock_ of the safe be such as to be practically unpickable, and that
carelessness shall not have placed the true key in the possession of the
thief.

There can be no doubt upon the mind of any mechanic or engineer,
thoroughly acquainted with practical working in metals, that a
good deal of what has been brought forward and affirmed, both by
safe-makers and by burglars themselves (turned approvers), as to the
wonderfully-ingenious devices resorted to by the latter, by which, if we
were to believe it all, nothing in the shape of steel or iron can
possibly withstand ultimately the redoubtable powers of these people, is
simply fiction--imaginary ingenuity utterly impracticable if tried.
Such, for example, is the notion of its being possible, by an ounce or
two of gunpowder exploded in the interior, to so blow asunder and
dislocate the parts of a well-made safe-lock that the bolts shall then
be easily got loose, or that a steel-plated safe which resists the drill
can be softened “by the blowpipe.” And just as absurd are some of the
wonderful pieces of ingenuity by which some of the burglars’ actual
devices are supposed to be met and frustrated; as, for example, one for
which we believe a patent has been obtained, consisting in filling-in
the hollow space between the inside and outside plates of the safe with
cast-iron bullets left loose. These might, no doubt, break a
_flat_-stemmed drill, after that had pierced the outer plate, but could
have no effect whatever upon a _round_-shanked drill, such as one of the
ordinary American spiral, or _teredo_-pointed drills.

That there are some methods of violence still untried, and yet at the
command of the burglar who dares to risk a tolerably loud noise of
explosive agents, is well known to skilful mechanical engineers, and for
obvious reasons it would be unwise that we should give any information
as to such; but the real practical and too-often effectual methods of
the burglar limit themselves almost entirely to the use of the
succession of steel wedges, followed by the powerful steel-pointed
pinching bar, or bars, to the forcing or prizing-screw, and to making
more or less way for this by cutting out beforehand by the pin-drill.

A safe, to be safe, must be so circumstanced or so constructed, or both,
that it should be able to resist the best efforts that can be made by
these methods for several hours; perhaps we might say as much as thirty
to thirty-six hours--viz., from Saturday night to Monday morning.

Now we hesitate not to say that the unsafeness of “safes” arises not
from any structural difficulty whatever, but almost always from the
parsimony and ignorance of those who purchase and employ them. Safes,
like razors, are made to sell, and if the public demand is for cheap
safes, such as we see every day advertised in the newspapers, it was
sure to have been, and is, met by a supply of things called safes which
are utterly unsafe. The great mass of the showy green and gold gewgaws
that one sees in the safe-shop windows, with flaming testimonials as to
their fire and burglar-proof powers, are simple shams: a genuine safe
could not be made at their prices.

The very first condition to constitute a genuine safe is that it shall
have an ample mass of metal--_i.e._, not of cast-iron, but of
wrought-iron, or best of steel, all round it; and especially that the
margins of metal all round the door shall be of such huge and surplus
scantling that no amount of wedging, by construction possible, should
be able to bend any one side sensibly. The next is that the workmanship
of every part of the safe be first-class: not that there be merely a
moulded door with a showy lock and a trumpery brass-plate upon it, but
that every corner and joint of plate with plate in sides and back be
effectually united and jointed in the best manner, and that the fitting
of the hardened edges of the door shall be like those of a valve, and
not even let a watch-spring be got in between. If these obvious
conditions be observed, and that the safe itself be properly posited in
the premises, it will be found, even with ordinary forms of construction
as to doors and bolts, but with a really unpickable lock, a very hard
nut for the best burglar to crack.

[Illustration: Chatwood’s Safes.]

But much more may be effected without any serious increase of cost.
Several forms of safes are now made, the rabbets of the doors of which
are so formed that it is almost a physical impossibility to get any
wedge, however thin, to drive in between the door and the frame. This is
effected in Chatwood’s patent safes (of Bolton and Manchester), as
figured above, by making the door rabbets in cross section
_curvilinear_, so that even if the fit be not so perfect but that the
edges of a very thin wedge can still be inserted, it yet cannot be
driven--for, as it goes forward, it must become curved, and if soft, so
as thus to bend, the thin steel will not bear the severe strain of
driving, but if hard, it breaks off into short bits close to the
entrance. In addition to this Chatwood’s (and we believe other makers’)
safes have bolts so constructed, as seen in the figure, that they _hook_
or lock into the bolt recesses in the frame in such a manner as to hold
the opposite sides of the frame together, so that, independent of its
own proper stiffness, it cannot be bent anywhere, unless by tearing
asunder the end on the iron bar constituting each cross-bolt. The bolts,
in fact, not only secure the door (as in ordinary) from opening, but
secure the door and frame together. With such a safe, if the owner will
only provide a proper position for it in his premises, he may rest
pretty easy in mind.

Safes are very commonly stood upon a wooden floor, or made to form part
of a wood-framed bookcase, or press, or stand in a recess. Often they
are comeatable all round, and even underneath, with nought but an inch
board below them, and almost always they are left with the front door
freely and fully exposed, and with ample and convenient room left all
round. This for two or three workmen to manipulate the safe as they may.

Now the only real conditions of safety are that the iron safe should be
bedded into brickwork set in Portland cement and sand; or, what is much
better, in hard granite or gritstone masonry, bedded in like manner.
Without this be done, a fire-proof safe is simply a delusion;
constructed how it may be, it is only a crucible of more or less
badly-conducting power, in which, after a time longer or shorter, deeds,
bank-notes, documents, &c., will be calcined, and coin or jewellery
melted, and gems flawed and destroyed. We say this in the full face of
the delusive so-called “fiery ordeals” to which many of the so-called
double-cased fire-proof safes are alleged to have been for hours
exposed. The safe should always be embedded in masonry, and rest upon
that in such a way that it cannot get undermined by either fire or
burglars.

Whenever the premises admit of it, the door of the safe itself should be
set back 10 or 12 inches from the face of the wall in which it is
embedded, and an outer door, flush with the face of the wall, should be
provided of iron, with a good lock and multiple bolts. The door of the
safe should open to the right; and if so, the outer door should open to
the left; and neither should open more than square to their position
when shut. No one but a practical workman or engineer can have an
adequate notion of the extent to which any mechanical operation upon the
door of a safe thus circumstanced is hampered by its being set back into
the wall, and with an outer door that even when open, cuts off all ready
manual access to the inner door from one side.

When premises are constructed, as they should be for all banks and
bullion merchants, jewellers, &c., having special regard to a safe as an
indisputably secure depository, then the safe should be completely iron
or steel cased, and embedded in hard stone masonry (we shall not here go
into additional special precautions against the remoter effects of
fire), covered in with a strong fire-brick arch, and with nothing but
the solid ground below. The door of the safe should only be approachable
through an iron or stone-lined passage, just the size of the safe-door,
and no more. This should be some feet in length, and have an outer
double-cased steel door, or perhaps that and an intermediate iron
falling-door or portcullis, between the outer door and the safe-door.
With a safe-door so circumstanced, even supposing both these outer doors
forced and open, it is almost impracticable for even a single workman,
however agile or adroit, to perform any mechanical operation whatever
upon the door, least of all upon its surrounding rabbates. These are so
close to the solid granite walls, starting out at right angles from the
rabbate all round, that he has no room to do anything; and to get a
prizing-bar at the door-rabbate, or even to get a second man to assist
the first in any way, is impossible, simply for want of room.

The whole of the doors and all the surfaces of such passage should be
painted a dull, lustreless black. No one who has not tried it, has any
idea of the difficulty of illuminating such a black passage, by even
several candles, sufficiently to perform any delicate mechanical
operation; and good light is essential to the safe-breaker.

In banks there is no better plan than has been ere now adopted of making
the iron safe a great cube, with the door at one side, placing the whole
safe with its bottom resting upon the stem or plunger of an hydraulic
press, the cylinder of which is fixed in the bottom of the pit in the
solid earth, of a size capable of enabling the whole safe to be bodily
lowered down into the cavity at the end of the day’s work, and pumped up
again out of its hiding-place the next morning. The lever of the
hydraulic pump is taken away, and the socket into which it fits is
plugged, and the plug locked into its place, and then the pump--situated
in a recess in solid masonry--is itself locked up. The top of the safe
itself, when it has been lowered to the bottom of its chamber, stands 10
or 12 inches below the floor-level of the stone floor, and a pair of
iron doors is then closed over it and locked down.

A safe executed in this way, though requiring a considerable expenditure
at first, if well done, might bid defiance to anything almost, even
unlimited gunpowder, for some days. The only addition of safety that
almost could be conceived would be that adopted at the bullion vaults of
the Bank of France in Paris, where these, situated in casemates two
stories under ground, are only approachable by one narrow, winding
staircase, which can be itself, in case of emergency, rapidly rendered
useless, and the cylindrical well in which it is placed filled up with
about 30 feet in depth of water, which cannot be pumped out until a
continuous supply be shut off by distant means only known to one or two
trusted employés.

Since this revision has been in type the great “safes’ contest” or wager
of battle between the rival safes of Mr. Herring of New York, and Mr.
Chatwood of Bolton, for £600 a side, has come off, at the International
Exhibition, Paris, Mr. R. Mallet and Mr. Robert F. Fairlie, C.E., being
the representatives of the English interests upon the occasion. The
result, which, owing to the conduct of some of the parties concerned,
assumed an unpleasant and incomplete form, may be found detailed fully
in a pamphlet published by Tinsley Brothers, London. It is referred to
here because, although no decision of the wager made could be come to,
the facts ascertained are of great interest and importance as respects
the proper construction of safes. They show conclusively that an
effectively constructed door and jambs is really the one thing needful
to absolute security, provided the safe itself be built up, as we have
urged, into masonry.

They also show that there are good grounds for doubting that the
American (Herring’s) “safe within safe” construction, with a thick mass
of so-called fire-proofing powdery composition between them, is at all
as protective against mere violence and the persevering use of wedges,
as Chatwood’s simpler but far more effective construction, especially of
his door and jambs. If one of the latter safes, wholly of steel plating,
be fairly embedded into masonry, and another outside flush door of his
construction, with curved rabbates and hooking locking bolts, be
supplied to the masonry ope itself, it is scarcely an exaggeration to
call such a safe “Invincible,” so far as anything that burglars, in any
civilised place in Europe at least, can effect.




INDEX.


  Adytic lock, 176;
    machine for manufacturing the keys of the, 185;
    number of changes in the lock, 188;
    advantages of, 189;
    discussion on its value, 192.

  Ainger on the Bramah lock, 111.

  Ainger’s lock, 61.

  Alarum lock, 40.

  American locks, 82;
    Stansbury’s lock, 83;
    Yale’s lock, 83;
    Dr. Andrews’s lock, 84;
    Day and Newell’s locks, 86;
    their Parautoptic lock, 89;
    Hobbs’s Protector lock, 99.

  Ancient locks, 8.

  Andrews’s lock, 84;
    snail wheel lock, 85.

  Appendix, 173.

  Aubin’s lock trophy, 166;
    locks forming it described, 168.


  Barron’s tumbler lock, 49;
    Bramah on, 68.

  Bird’s tumbler lock, 52.

  Bramah on Barron’s tumbler lock, 68;
    on the defects of the tumbler lock, 68;
    on the defects of the warded lock, 66.

  Bramah lock, 70;
    cylinder lock, 73;
    number of changes in the Bramah lock, 81;
    picked by Mr. Hobbs, 121;
    report of the arbitrators, 123, 124;
    a description of the lock picked, 125;
    letters from Messrs. Bramah questioning the fairness of the trial,
    126;
    method of picking, 110;
    method employed by Mr. Hobbs, 129;
    Ainger on the Bramah lock, 110;
    Farey on the Bramah lock, 113;
    improvements made since 1851, 131.

  Brown’s letter lock, 23;
    picked by Mr. Hobbs, 139.

  Bullion vaults of the Bank of France, 206.


  Chatwood’s safes described, 203.

  Chinese locks, 171.

  Chubb on Davies’s lock, 112;
    on lock picking, 132.

  Chubb’s lock, 53;
    described, 54, 56;
    key of, 57;
    attempt to pick, 58;
    experiments on, 59;
    number of changes in the lock, 55;
    the detector lock picked by Mr. Hobbs, 115;
    value of the detector questioned, 117;
    improvements, 121;
    Mr. Hodge on the Chubb lock, 114;
    Chubb’s new locks, 147;
    bank locks, 149.

  Clockwork, application of, to locks, 39.

  Closet-lock, 17.

  Commercial importance of locks, 2.

  Contrivances for adding to the security of locks, 35.

  Cut locks, 18.


  Davies’s lock, Captain O’Brien on 112;
    Mr. Chubb on, 112.

  Davis’s lock, 60.

  Day and Newell’s lock, 86;
    Parautoptic lock, 89 _et seq._

  Dead-lock, 17.

  Denison’s large lock, 142;
    small ditto, 146.

  Dial locks, 23;
    method of picking, 138.

  Duhamel du Monceau’s _Art du Serrurier_, 4.


  Egyptian door-fastenings, 13.

  Egyptian pin-lock, 14;
    method of picking, 139.

  Escutcheon, uses of the, explained, 37.

  Exhibition of 1851, effects of the, in improving English locks, 140;
    Jury Report on locks, 131;
    observations on the Report, 133.


  Farey on the Bramah lock, 113.

  Fenby on warded locks, 173;
    on tumbler locks, 174.

  Fenby’s adytic lock, 176;
    machine for making the keys of, 185;
    number of changes in the, 188;
    advantages of, 189;
    discussion on the value of the lock, 192;
    stop-lock, 196;
    machines for the manufacture of the locks, 200.

  Fons, Mr. de la, his improvement in locks, 148.

  French locks, ancient, 32.

  Friend’s secret lock, 39.


  Greek locks, 9.


  Hobbs on English locks made before 1851, 115;
    he picks a Chubb lock, 116;
    a Bramah lock picked by Mr. Hobbs, 122;
    his mode of picking the Bramah lock described, 129;
    Mr. Brown’s letter-lock picked by him, 139.

  Hobbs’s protector lock, 99.

  Hodge on the Chubb lock, 114.


  Iron-rim lock, 17.

  Iron safes, value of, 201;
    the best position for a safe, 204;
    chamber for jewellers’ safes described, 205;
    arrangement of bank safes, 205;
    Chatwood’s safes, 203.


  Kemp’s union lock, 81.

  Keys, master, 31;
    skeleton, 30;
    Mackinnon’s key, 62;
    Machin’s web key, 154.

  Knob lock, 17.


  Lacedæmonian lock, 11.

  Left-hand lock, 17.

  Letter locks, 22;
    method of picking, 138.

  Lever locks, 43.

  Literature of lock-making, 4;
    list of references to the “Transactions of the Society of Arts”
    relating to lock-making, 166.

  Lock classification, 17.

  Lock controversy, 102;
    previous to the Great Exhibition, 103;
    Mr. Chubb on Davies’s lock, 112;
    Captain O’Brien on Davies’s and other locks, 112;
    Mr. Farey on the Bramah lock, 113;
    Mr. Hodge on locks, 114;
    lock controversy during and since the Great Exhibition, 115;
    Mr. Hobbs on English locks, 115;
    he picks the Chubb lock, 116;
    the Bramah lock picked by him, 121;
    statements of Messrs. Bramah, 125;
    attempt of Messrs. Garbutt to pick the parautoptic lock, 134.

  Lock manufacture at Wolverhampton, state of, described, 154.

  Lock-picking, distinction between “picking” and “ringing the changes”
  on a lock, 136;
    tentative process of picking, 110;
    method of picking letter and dial locks, 138;
    mode of picking the Egyptian lock, 139;
    method of picking tumbler locks, 118;
    method of picking the Yale lock, 140;
    Mr. Chubb on lock-picking, 132;
    contrivances to prevent the picking of locks, 105.

  Lock trophy, Aubin’s, 166;
    locks composing the, described, 168.

  Lock and key, improved, 176.

  Locks, English patents for, 164;
    Jury Report, Exhibition of 1851, on, 131;
    observations on the Report, 133;
    effects of the Exhibition of 1851 in improving English locks, 140;
    use of machinery in the manufacture of, 163, 200.

  Locks, &c., invented by the Marquis of Worcester, 35.

  Locks and keys, literature of, 4;
    list of references in the “Transactions of the Society of Arts”
    relating to, 166.

  Louis XVI., his fondness for lock-making, 26, 35.


  Machin’s web key, 61.

  Mackinnon’s key, 62.

  Manufacture of locks and keys at Wolverhampton, state of the, 154.

  Marshall’s secret escutcheon, 37.

  Master keys, 31.

  Meighan’s alarum lock, 40.

  Mitchell and Lawton’s tumbler lock, 52.

  Mortise locks, 17, 18.

  Multiple-bolt locks, 41,


  Nettlefold’s lock, 60.

  Newell’s parautoptic lock, 89.


  O’Brien, Captain, on Davies’s lock, 112.

  Owen’s experiments on Chubb and Bramah locks, 59.


  Parautoptic lock, 89;
    key, 91;
    Austrian Report on, 93;
    English patent for, 98;
    attempts to pick the, in America, 106;
    Report of the American Institute on the lock, 107;
    latest challenge issued by Messrs. Day and Newell, 108;
    Mr. Garbutt’s attempt to pick the, 134;
    failure of the attempt, 135.

  Parnell’s defiance lock, 141.

  Parson’s lock, 61.

  Patents, English, for locks, 164.

  Pin-lock of Egypt, 14.

  Puzzle-lock, 19.


  Regnier’s puzzle locks, 21.

  Right-hand lock, 17.

  Ring lock, 17.

  Roman locks, 10.

  Rowntree’s tumbler lock, 50.

  Russell’s screw-lock for casks, 38.

  Russian locks, 171.

  Rutherford’s lock, 39.

  Ruxton’s detector for tumbler locks, 53.


  Safes, value of iron, 201;
    Chatwood’s, 203;
    see also _Iron Safes_.

  Saxby’s prize lock, 152;
    picked by Mr. Hobbs, 153.

  Screw locks, 38.

  Skeleton keys, 30.

  Society of Arts’ prize lock, 30.

  Somerford’s lock, 60.

  Spring-stock lock, 17.

  Stansbury’s lock, 83.

  Stop lock, Fenby’s, 196.

  Straight locks, 18.


  Tentative process of lock-picking, 110.

  Three-bolt lock, 17.

  Tumbler locks, 43;
    lock described by M. de Réaumur, 46;
    modern tumbler lock, 52;
    introduction of the detector, 53;
    Chubb’s lock, 53, 56;
    key of, 57;
    advantages and defects of tumbler locks, 63;
    Hobbs’s method of adjustment, 63.

  Tumbler locks, Mr. Fenby on, 174;
    method of picking, 118;
    double action, 49.

  Two-bolt lock, 17.


  Ward locks, 18.

  Warded locks, 27;
    action of the key on the wards, 28;
    insecurity of, 29;
    warded locks of the last century, 31;
    insecurity of, illustrated by Mr. Chubb, 34;
    Bramah on the defects of, 66;
    Mr. Fenby on, 173.

  Wheel locks, 18.

  Wheel and pinion, application of, to locks, 39.

  Williams’s lock, 62.

  Wolverhampton, account of the state of the lock and key manufacture
  at, 154.

  Worcester, inventions of the Marquis of, relating to lock-making, 35.


  Yale’s lock, 83;
    method of picking, 140.

  Yale’s cylinder lock, 152.


PRINTED BY VIRTUE AND CO., CITY ROAD, LONDON.




      *      *      *      *      *      *




Transcriber’s note:

  Inconsistent spelling and hyphenation have not been standardised.

  The calculations in the text regarding the number of combinations and
  permutations have been transcribed without further comment, even when
  they might be open to discussion.

  The reference letters and numbers given in the descriptions of
  illustrations are not always present in these illustrations, but they
  may be present in other illustrations of the same object.

  Page 33, "S S, O O, Z Z, are ornaments fastened on at _b c d_": this
  does not appear to be in accordance with the illustrations.

  Page 153, footnote [11]: these figures are not present in this book.

  Page 164: “As no complete list ...: the closing quote mark is missing.

  Page 164 ff, table, entry 1784: the date column was blank in the
  source document.


  Changes made

  Footnotes have been moved to under the paragraph in which they were
  referenced.

  Page 9: closing quote mark inserted after "curious knot".

  Page 45: "receptacles at C _d_" changed to "receptacles at _c d_".

  Page 48: fig. 23 was printed upside-down in the source document.

  Page 51: "the notches _f_ or _g_ in the bolt" changed to "the notches
  _s_ or _g_ in the bolt", cf. fig. 26.

  Page 57: "the notches _n n_" changed to "the notches _n n´_".

  Page 77: "shewn at _a a_ in fig. 37" changed to "shewn at _a´ a´_ in
  fig. 37"; "3, 2, 3" changed to "3, 2, 3´".

  Page 89: "T the third" changed to "T³ the third" cf. illustration.

  Page 100: "piece of metal _h p_" changed to "piece of metal _h h_" cf.
  illustration.

  Page 104: "ged" changed to "get".