[Illustration: PIERRE CURIE IN 1906.
Hellog Dujardin Dujardin
Imp. Ch. Wütmann]




                           PIERRE CURIE




                                BY

                            MARIE CURIE




                          _Translated by
                   CHARLOTTE AND VERNON KELLOGG_




                       WITH AN INTRODUCTION
                  BY MRS. WILLIAM BROWN MELONEY
                    AND AUTOBIOGRAPHICAL NOTES
                          BY MARIE CURIE




                          _ILLUSTRATED_




                             NEW YORK

                      THE MACMILLAN COMPANY

                               1923




Copyright, 1923,
By MARIE CURIE.




"It is possible to conceive that in criminal hands radium might prove
very dangerous, and the question therefore arises whether it be to the
advantage of humanity to know the secrets of nature, whether we he
sufficiently mature to profit by them, or whether that knowledge may not
prove harmful. Take, for instance, the discoveries of Nobel--powerful
explosives have made it possible for men to achieve admirable things,
but they are also a terrible means of destruction in the hands of those
great criminals who draw nations into war. I am among those who believe
with Nobel that humanity will obtain more good than evil from future
discoveries."

              PIERRE CURIE,

                   _Nobel Conference, 1903._




TRANSLATORS' NOTE


The translators wish to acknowledge their obligations to Dr. R. B.
Moore, Chief Chemist, U. S. Bureau of Mines, and an American authority
on radium, who kindly read the whole translation in manuscript in order
to assure its accuracy as to the technical details referred to by Madame
Curie in her account of the work of her husband and herself on radium.




PREFACE


It is not without hesitation that I have undertaken to write the
biography of Pierre Curie. I should have preferred confiding this task
to some relative or some friend of his infancy who had followed his
whole life intimately and possessed as full a knowledge of his earliest
years as of those after his marriage. Jacques Curie, Pierre's brother
and the companion of his youth, was bound to him by the tenderest
affection. But after his appointment to the University of Montpellier, he
lived far from Pierre, and he therefore insisted that I should write the
biography, believing that no one else better knew and understood the
life of his brother. He communicated to me all his personal memories;
and to this important contribution, which I have utilized in full, I
have added details related by my husband himself and a few of his
friends. Thus I have reconstituted as best I could that part of his
existence that I did not know directly. I have, in addition, tried
faithfully to express the profound impression his personality made upon
me during the years of our life together.

This narrative is, to be sure, neither complete nor perfect. I hope,
nevertheless, that the picture it gives of Pierre Curie is not deformed,
and that it will help to conserve his memory. I wish, too, that it might
remind those who knew him of the reasons for which they loved him.

                             M. C.




CONTENTS

Introduction

CHAPTER

I. The Curie Family. Infancy and First
Studies of Pierre Curie

II. Dreams of Youth. First Scientific Work.
Discovery of Piezo-Electricity

III. Life as the Director of Laboratory Work
in the School of Physics and Chemistry.
Generalization of the Principle of Symmetry.
Investigations of Magnetism

IV. Marriage and Organization of Family Life.
Personality and Character

V. The Dream Become a Reality. The Discovery
of Radium

VI. The Struggle for Means to Work. The Burden
of Celebrity. The First Assistance
from the State. It Comes Too Late

VII. The Nation's Sorrow. The Laboratories:
"Sacred Places"

Autobiographical Notes--Marie Curie




ILLUSTRATIONS

Pierre Curie in 1906.

Pierre and Marie Curie in their laboratory, where
radium was discovered.

A view of the extraction of radium in the old shed
where the first radium was obtained.

Pierre Curie with the quartz piezo-electroscope he invented,
by which rays of radium are measured.

A view of the extraction of radium in the old shed
where the first radium was obtained.

Mme. Curie instructing American soldiers in her
Paris laboratory.

Madame Curie in her laboratory at the Institut Curie,
Paris.

Mme. Curie and President Harding at the White
House, May 20, 1921, when a gram of radium was
presented to its discoverer by the women of
America.




PIERRE CURIE




THE LIFE STORY OF
PIERRE CURIE




INTRODUCTION

BY MRS. WILLIAM BROWN MELONEY


Every little while a man or a woman is born to serve in some big way.
Such a one surely is Marie Curie. Her discovery of radium has advanced
science, relieved human suffering and enriched the world. The spirit in
which she has done her work has challenged the minds and souls of men.

One morning in the spring of 1898, when the United States was going to
war with Spain, Madame Curie stepped forth from a crude shack on the
outskirts of Paris, with the greatest secret of the century literally in
the palm of her hand.

It was one of the silent, unheralded great moments in the world's
history.

The discovery which had become a fact that morning was no accident. It
was a triumph over hardship and doubting men. It represented years of
patient labor. Madame Curie and her husband, Pierre Curie, had wrested
from Mother Earth one of her most priceless secrets.

I have been asked to tell why I undertook the Marie Curie Radium
Campaign and how I persuaded Madame Curie to write this book.

It is with much hesitancy that I venture to write a preface to this
book. She once chided me, in her gentle way, for an article in which I
had stated facts with some feeling--although the facts praised her. "In
science," she said, "we should be interested in things, not persons."

Madame Curie is the most modest of women. It is only after long
persuasion that she has consented to record the autobiographical notes
contained in this book. Still, so much has been left unsaid,
uninterpreted, that I feel an obligation to say a word toward a fuller
understanding of this great and noble character.

In 1915 I wrote in my editor's suggestion book: "Greatest woman's story
in the world--Marie Curie, discoverer of radium."

For the next four years scarcely any writer of prominence went abroad
without a commission from me to bring back the story of Madame Curie.
Always they returned with the report: "She was not to be found," or "She
was at the front somewhere," or "She won't see journalists." My own
letters to Madame Curie brought no reply. I did not know then that great
bags of mail from all parts of the world lay piled up in her laboratory
where there was no secretary, while Madame Curie with her X-ray
apparatus was at the front, relieving suffering and saving lives.

In May, 1919, another mission took me to Paris and I resolved to see
Madame Curie myself. My friend, Stéphane Lauzanne, Editor-in-Chief of
_Le Matin_, said: "Give it up. Become interested in something else; she
will see no one. She does nothing but work."

I began to ask questions.

"She is very simple and exceedingly retiring," said Lauzanne. "Few
things in life are more distasteful to her than publicity. Her mind is
as exact and logical as science itself. She cannot accept or understand
exaggerations and inaccurate quotations. She cannot understand why
scientists, rather than science, should be discussed in the press. There
are but two things for her--her little family and her work.

"After the death of Pierre Curie, the faculty and officials of the
University of Paris decided to depart from all precedent and appoint a
woman to a full professorship at the Sorbonne. Madame Curie accepted the
appointment and the date was set for her installation.

"It was the history-making afternoon of October 5th, 1906. The members
of the class which had formerly been instructed by Professor Pierre
Curie were seated in one group.

"There was present a large crowd--celebrities, statesmen, academicians,
all the faculty. Suddenly through a small side door entered a woman all
in black, with pale hands and high arched forehead. The magnificent
forehead won notice first. It was not merely a woman who stood before
us, but a brain--a living thought. Her appearance was enthusiastically
applauded for five minutes. When the applause died down, Madame Curie
bent forward with slightly trembling lips. We wondered what she was
about to say. It was important. It was history, whatever she said.

"In the foreground sat a stenographer, ready to record her words. Would
she speak of her husband? Would she thank the Minister and the public?
No, she began quite simply as follows:

"'When we consider the progress made by the theories of radio-activity
since the beginning of the Nineteenth Century--' The important thing to
this great woman is work. Time should not be wasted in idle words. And
so, dispensing with all superficial formality, with no betrayal of the
tremendous emotion which all but overcame her--except by the extreme
pallor of her face and the trembling of her lips--she continued her
lecture in clear, well-modulated tones.

"It was typical of this great soul that she should carry on their work
courageously and without faltering.

"You will see," concluded Lauzanne, "it is useless to try to interrupt
her work for interviews."

Later I met one of Madame Curie's fellow scientists who sympathized with
my desire, but who agreed with Lauzanne that an interview was
impossible. Finally, however, he promised to carry a letter to Madame
Curie.

I wrote ten letters and destroyed them. In one I said: "My father, who
was a medical man, wrote: 'It is impossible to exaggerate the
unimportance of people.' But you have been important to me for twenty
years, and I want to see you a few minutes."

The answer came within an hour. I was to go to the laboratory the next
morning.

I had been in Mr. Edison's laboratory a few weeks before sailing from
home. Edison is rich in the material things--as he should be. Every kind
of equipment is at his command. He is a power in the financial as well
as the scientific world. In my childhood I had lived near Alexander
Graham Bell; had admired his great house and his fine horses. A short
time before, I had been in Pittsburgh, where the sky is plumed by the
tall smoke stacks of the greatest radium reduction plants in the world.

I remembered that millions of dollars had been spent on radium watches
and radium gun sights. Several millions of dollars' worth of radium was
even then stored in various parts of the United States. I had been
prepared to meet a woman of the world, enriched by her own efforts and
established in one of the white palaces of the Champs d'Elysées or some
other beautiful boulevard of Paris.

I found a simple woman, working in an inadequate laboratory and living
in a simple apartment on the meager pay of a French professor.

As I entered the new building at Number One Rue Pierre Curie, which
stands out conspicuously among the old walls of the University of Paris,
I had already formed a picture of the laboratory of the discoverer of
radium.

I waited a few minutes in the bare little office which might have been
furnished from Grand Rapids, Michigan. Then the door opened and I saw a
pale, timid little woman in a black cotton dress, with the saddest face
I had ever looked upon.

Her well-formed hands were rough. I noticed a characteristic, nervous
little habit of rubbing the tips of her fingers over the pad of her
thumb in quick succession. I learned later that working with radium had
made them numb. Her kind, patient, beautiful face had the detached
expression of a scholar. Suddenly I felt like an intruder.

I was struck dumb. My timidity exceeded her own. I had been a trained
interrogator for twenty years, but I could not ask a single question of
this gentle woman in a black cotton dress. I tried to explain that
American women were interested in her great work, and found myself
apologizing for intruding upon her precious time. To put me at my ease,
Madame Curie began to talk about America. She had for many years wanted
to visit my country, but she could not be separated from her children.

"America," she said, "has about fifty grammes of radium. Four of these
are in Baltimore, six in Denver, seven in New York." She went on naming
the location of every grain.

"And in France?" I asked.

"My laboratory," she replied simply, "has hardly more than a gramme."

"_You_ have only a gramme?" I exclaimed. That meant less than
one-twenty-ninth of an ounce.

"I? Oh, I have none," she corrected. "It belongs to my laboratory."

I suggested royalties on her patents. Surely she had protected her right
to the processes by which radium is produced. The revenue from such
patents should have made her a very rich woman.

Quietly, and without any seeming consciousness of the tremendous
renunciation, she said, "There were no patents. We were working in the
interests of science. Radium was not to enrich any one. Radium is an
element. It belongs to all people."

She had contributed to the progress of science and the relief of human
suffering, and yet, in the prime of her life she was without the tools
which would enable her to make further contribution of her genius.

"If you had the whole world to choose from," I asked impulsively, "what
would you take?" It was a silly question, perhaps, but as it happened,
a fateful one.

"You ought to have everything in the world you need to go on with your
work," I said. "Some one must undertake this."

"Who will?" she asked rather hopelessly.

"The women of America," I promised--and then I rose to go.

That week I learned that the market price of a gramme of radium was one
hundred thousand dollars. I also learned that Madame Curie's laboratory,
although practically a new building, was without sufficient equipment;
that the radium held there was used at that time only for extracting
emanations for hospital use in cancer treatment.

I saw Madame Curie at the Institute again and then in her own home--a
small apartment in the Ile St. Louis, where she lived with her two
daughters. It was a happy, busy little family. They had no protest
against life except to regret that lack of equipment interfered with the
important research work Madame Curie and her daughter, Irene, should
have been doing.

It was my hope when I arrived in New York, a few weeks afterwards, to
find ten women to subscribe ten thousand dollars each for the purchase
of a gramme of radium, and in this way to enable Madame Curie to go on
with her work, without the publicity of a general campaign. That hope
was soon dashed. I found one or two such women, but not ten.

There were not ten to buy that gramme of radium but there were a hundred
thousand women and a group of men to help, who determined the money must
be raised.

My first direct and substantial support came from Mrs. William Vaughn
Moody, widow of the American poet and playwright.

When we found it would be necessary to launch a national campaign, Mrs.
Robert G. Mead, a doctor's daughter, and one who had been a standby in
cancer prevention work, became secretary, and Mrs. Nicholas F. Brady an
executive member of the committee. Behind these women stood a group of
scientific men, who knew what radium had meant to humanity, among them
Dr. Robert Abbe, the first American surgeon to use radium, and Dr.
Francis Carter Wood.

In less than a year the fund had been raised.

Stéphane Lauzanne describes a second impressive moment in the life of
Madame Curie. It was nearly a year after my talk with her. It was
fifteen years since that scene at the University of Paris. These years
had been spent in her laboratory; she had made no public appearance. It
was in March, 1921, that Monsieur Lauzanne heard her voice again.

"I lifted the telephone receiver," he relates, "and heard these words:
'Madame Curie wishes to speak to you.' What extraordinary event--what
tragedy, perhaps, might this not mean? And suddenly, over the wire came
the sound of the voice which I had heard only once before, but which had
stayed in my memory--the same voice which had once pronounced the words,
'When we consider the progress made by the theories of radio-activity
since the beginning of the Nineteenth Century----'

"'I wanted to tell you that I am going to America,' she said. 'It was
very hard for me to decide to go, because America is so far and so big.
If some one did not come for me, I should probably never have made the
trip. I should have been too frightened. But to this fear is added a
great joy. I have devoted my life to the science of radio-activity and I
know all we owe to America in the field of science. I am told you are
among those who strongly favor this distant trip, so I wanted to tell
you I have decided to go, but please don't let any one know about it.'

"This great woman--the greatest woman in France--was speaking haltingly,
tremblingly, almost like a little girl. She, who handles daily a
particle of radium more dangerous than lightning, was afraid when
confronted by the necessity of appearing before the public."

A little later, when Madame Curie and I had embarked for America, where
she was to receive her radium and other experimental material, I asked
her if, the day I had first given her the promise, she had believed that
American women would rally to her aid.

"No," she confessed honestly, "but I knew you were sincere."

About the time of her marriage, one of her relatives gave Madame Curie a
gift of money to be used for a trousseau. It was not a great sum, but
important to the poor student in Paris. To understand the significance
of the use to which she put this fund, it is necessary to remember that
Marie Sklodowska was young, and possessed physical beauty and charm. She
was not without appreciation of the beautiful, and she could not
possibly have been utterly unconscious of her own appearance. She had a
young girl's natural interest in pretty clothes. She considered the
purchase of a wedding gown and other personal belongings, and then, with
her characteristic exactness, measured her needs and the future.

She was married in a simple dress she had brought from Poland, and her
trousseau fund was spent on two bicycles, so that she and Pierre Curie
might enjoy the beautiful country of France. That was their honeymoon.

One dream that Madame Curie held, and still holds unrealized, is the
hope of a quiet little home of her own with a garden and hedge, and
flowers and birds. During her American travels, she would frequently
glance through the window as the train passed through a small town, and,
spying some modest little house with a garden, would say, "I have always
wanted such a little home."

But owning a house was secondary in the life of both Pierre and Marie
Curie. They simply made a home wherever they lived, for such money as
might have gone for the purchase of her little dream house was always
needed in the laboratory. She told me one day, with deep feeling, that
one of the regrets of her life was that Pierre Curie had died without
ever having had a permanent laboratory.

She had, as I have said, refused opportunities to come to the United
States because she could not endure separation from her children. She
was, I think, finally persuaded to face the long trip and the terrifying
publicity attending it, partly because of her gratitude for the support
given her scientific work, but principally because it offered a splendid
opportunity for travel to her daughters.

There is in Madame Curie none of the legendary coldness and
thoughtlessness attributed to the scientist. During the war, when she
ran her own radiological truck and lived on the march from hospital to
hospital in the zone of operations, she washed and dried and pressed her
own clothes. Once during our American travels, we stayed in a home where
there were several other house guests besides our party of five. I
entered Madame Curie's room and found her washing her underclothes.

"It is nothing at all," she said, when I protested. "I know perfectly
well how to do it, and with all of these extra guests in the house, the
servants have enough to do."

On the night before the reception at the White House, at which President
Harding was to present the gramme of radium to Madame Curie, the Deed
was brought to Madame Curie. It was a beautifully engraved scroll,
prepared in the office of Coudert Brothers, vesting all rights to a
gramme of radium, the gift of American women, in Madame Curie.

She read the paper carefully, and then, after a few moments of thought,
said: "It is very fine and generous, but it must not be left this way.
This gramme of radium represents a great deal of money, but more than
that, it represents the women of this country. It is not for me; it is
for science. I am not well; I may die any day. My daughter Eve is not of
legal age, and if I should die it would mean that this radium would go
to my estate and would be divided between my daughters. It is not for
that purpose. This radium must be consecrated for all time to the use of
science. Will you have your lawyer draw a paper which will make this
very clear?"

I said that it would be done in a few days.

"It must be done to-night," she said. "To-morrow I receive the radium,
and I might die tomorrow. Too much is at stake."

And so, late as it was on that hot May evening, after some difficulty,
we secured the services of a lawyer, who prepared the paper from a draft
Madame Curie herself had written. She signed it before starting for
Washington.

This document read:

"In the event of my death I give to the Institut du Radium, of Paris,
for exclusive use in the Laboratoire Curie, the gramme of radium which
was given to me by the Executive Committee of Women of the Marie Curie
Radium Fund, pursuant to an agreement dated the 19th day of May, 1921."

This act was consistent with the whole life of the discoverer of radium;
with the answer she had made to my question a year before:

"Radium is not to enrich any one. It is an element; it is for all
people."

During her American travels, I repeatedly requested Madame Curie to
write the story of her life. I urged its importance to history and its
influence among students preparing to consecrate their lives to science.

Finally she consented. "But it will not be much of a book," she said.
"It is such an uneventful, simple little story. I was born in Warsaw of
a family of teachers. I married Pierre Curie and had two children. I
have done my work in France."

A simple statement, but fraught with what meaning! When most of us shall
have been forgotten, when even the Great World War shall have dwindled
to a few pages in the history books, when Governments shall have fallen
and risen and fallen again, the work of Marie Curie will be remembered.

Of her work and her husband's, volumes--veritable libraries--have been
written since that spring morning in 1898, when after an all night vigil
in a shack on the outskirts of Paris, she came forth with the great gift
of radium to mankind. Scientists will go on adding to the bibliography
of the marvelous element. But of Marie Curie herself, the woman, it is
unlikely that the world will ever read more than the brief notes which
compose this small book.

It is her conviction, her philosophy, that "In science we should be
interested in things, not persons."




CHAPTER I

THE CURIE FAMILY. INFANCY AND FIRST
STUDIES OF PIERRE CURIE


Pierre Curie's parents, who were educated and intelligent, formed a part
of the _petite bourgeoisie_ of small means. They did not frequent
fashionable society, but confined themselves entirely to the
companionship of their relatives and a few intimate friends.

Eugène Curie, Pierre's father, was a physician and the son of a
physician. He knew very few kinsmen of his name, and very little about
the Curie family, which was of Alsatian (Eugène Curie was born at
Mulhouse in 1827) and Protestant origin. Even though his father was
established in London, Eugène had been brought up in Paris, where he
pursued his studies in the natural sciences and medicine, and worked as
preparator under Gratiollet in the laboratories of the Museum.

Doctor Eugène Curie's remarkable personality impressed all who
approached him. He was a tall man, who in youth must have been blonde,
with beautiful blue eyes of a clearness and brilliancy that were
striking even in an advanced old age. These eyes, which had retained a
child-like expression, reflected goodness and intelligence. He had
indeed unusual intellectual capacities, a very live aptitude for the
natural sciences, and the temperament of a scholar.

Although he wished to consecrate his life to scientific work, family
responsibilities following his marriage and the birth of two sons forced
him to renounce this desire. The necessities of life obliged him to
practice his medical profession. He continued, however, such
experimental research as his means permitted, in particular undertaking
an investigation upon inoculation for tuberculosis at a time when the
bacterial nature of this malady was not yet established. His scientific
avocations developed in him the habit of making excursions in search of
the plants and animals necessary to his experiments, and this habit, as
well as his love of Nature, gave him a marked preference for country
life. Until the end of his life he conserved his love for science, and,
without doubt, also, his regret at not having been able to devote
himself exclusively to it.

His medical career remained always a modest one, but it revealed
remarkable qualities of devotion and disinterestedness. At the time of
the Revolution of 1848, when he was still a student, the Government of
the Republic conferred on him a medal, "for his honorable and courageous
conduct" in serving the wounded. He himself had been struck, on February
24th, by a ball which shattered a part of his jaw. A little later,
during a cholera epidemic, he installed himself, in order that he might
look after the sick, in a quarter of Paris deserted by physicians.
During the Commune he established a hospital in his apartment (rue de la
Visitation) near which there was a barricade, and there he cared for the
wounded. Through this act of civism and because of his advanced
convictions he lost a part of his _bourgeois_ patronage. At this time he
accepted the position of medical inspector of the organization for the
protection of young children. The duties of this post permitted him to
live in the suburbs of Paris where health conditions for himself and his
family were much better than those of the city.

Doctor Curie had very pronounced political convictions. Temperamentally
an idealist, he had embraced with ardor that republican doctrine which
inspired the revolutionaries of 1848. He was united in friendship with
Henri Brisson and the men of his group. Like them, a free thinker and an
anticlerical, he did not have his sons baptized, nor did he have them
practice any form of religion.

Pierre's mother, Claire Depouilly, was the daughter of a prominent
manufacturer of Puteaux, near Paris. Her father and brothers
distinguished themselves through their numerous inventions connected
with the making of dyes and special tissues. The family, which was of
Savoy, was caught in the business catastrophe caused by the Revolution
of 1848, and ruined. And these reverses of fortune, added to those which
Doctor Curie had experienced during his career, meant that he and his
family lived always in comparatively straightened circumstances, with
the difficulties of existence often renewed. Even though raised for a
life of ease, Pierre's mother accepted with tranquil courage the
precarious conditions which life brought her, and gave proof of an
extreme devotion as she made life easier for her husband and children by
her activity and her good will.

If the circumstances in which Jacques and Pierre grew up were modest and
not free from cares, nevertheless there reigned in the family an
atmosphere of gentleness and affection. In speaking to me for the first
time of his parents, Pierre Curie said that they were "exquisite."
They were, in truth, that. The father's spirit was a little
authoritative--always awake and active. And he possessed a rare
unselfishness. He neither wished nor knew how to profit by personal
relations to ameliorate his condition. He loved his wife and sons
tenderly, and was ever ready to aid all who needed him. The mother was
slight, vivid in character, and, even though her health had suffered
through the birth of her sons, was always gay and active in the simple
home that she so well knew how to make attractive and hospitable.

When I first knew them they lived at Sceaux, rue des Sablons (to-day rue
Pierre Curie) in a little house of ancient construction half concealed
amidst the verdure of a pretty garden. Their life was peaceful. Doctor
Curie went where his duties called him, either in Sceaux or in
neighboring localities. Beyond this he occupied himself with his garden
or his reading. Near relatives and neighbors came to visit on Sundays,
when bowling and chess were the favorite amusements. From time to time
Henri Brisson sought out his old companion in his tranquil retreat.
Great calm and serenity enveloped the garden, the dwelling, and its
inhabitants.

Pierre Curie was born the 15th of May, 1859, in a house facing the
Jardin des Plantes, rue Cuvier, where his parents lived at the time when
his father was working in the Museum laboratories. He was the second son
of Doctor Curie and three and a half years younger than his brother
Jacques. In after life he retained few particularly characteristic
memories of his childhood in Paris; yet he did tell me how vividly
present in his mind were the days of the Commune, the battle on the
barricade so near the house where he then lived, the hospital
established by his father, and the expeditions, on which his brother
accompanied him, in search of the wounded.

It was in 1883 that Pierre moved with his parents from the capital to
the suburbs of Paris, living first, from 1883 to 1892, at
Fontenay-aux-Roses, then at Sceaux from 1892 to 1895, the year of our
marriage.

Pierre passed his childhood entirely within the family circle; he never
went to the elementary school nor to the lycée. His earliest
instruction was given him first by his mother and was then continued by
his father and his elder brother, who himself had never followed in any
complete way the course of the lycée. Pierre's intellectual capacities
were not those which would permit the rapid assimilation of a prescribed
course of studies. His dreamer's spirit would not submit itself to the
ordering of the intellectual effort imposed by the school. The
difficulty he experienced in following such a program was usually
attributed to a certain slowness of mind. He himself believed that he
had this slow mind and often said so. I think, however, that this belief
was not entirely justified. It seems to me, rather, that already from
his early youth it was necessary for him to concentrate his thought with
great intensity upon a certain definite object, in order to obtain a
precise result, and that it was impossible for him to interrupt or to
modify the course of his reflections to suit exterior circumstances. It
is clear that a mind of this kind can hold within itself great future
possibilities. But it is no less clear that no system of education has
been especially provided by the public school for persons of this
intellectual category, which nevertheless includes more representatives
than one would believe at first sight.

Very fortunately for Pierre, who could not, as we can see, become a
brilliant pupil in a lycée, his parents had a sufficiently keen
intelligence to understand his difficulty, and they refrained from
demanding of their son an effort which would have been prejudicial to
his development. If, then, Pierre's earliest instruction was irregular
and incomplete, it had the advantage of not so weighing on his
intelligence as to deform it by dogmas, prejudices or preconceived
ideas. And he was always grateful to his parents for this very liberal
attitude. He grew up in all freedom, developing his taste for natural
science through his excursions into the country, where he collected
plants and animals for his father. These excursions, which he made
either alone or with one of the family, helped to awake in him a great
love of Nature, a passion which endured to the end of his life.

Intimate contact with Nature, which, because of the artificial
conditions of city life and of traditional education, few children can
know, had a decisive influence on Pierre's development. Guided by his
father, he learned to observe facts and to interpret them correctly. He
became familiar with the animals and plants of the environs of Paris. He
knew which ones could be found at each season of the year in the forests
and fields, the streams and ponds. The ponds in particular had for him
an ever new attraction with their characteristic vegetation and their
population of frogs, tritons, salamanders, dragonflies, and other
denizens of air and water. No efforts to obtain the objects of his
interests seemed too great for him. He never hesitated to take any
animal in his hands in order to examine it more closely. Later, after
our marriage, in our walks together, if I made some objection to letting
him put a frog into my hands, he would exclaim: "But no, see how pretty
it is!" He loved always, too, to bring back bouquets of wild flowers
from his walks.

Thus his knowledge of natural history progressed rapidly. At the same
time, also, he was mastering the elements of mathematics. His classical
studies, on the contrary, had been much neglected, and it was
principally through general reading that he acquired a knowledge of
literature and history. His father, who was widely cultured, possessed a
library containing many French and foreign works. Having himself a very
pronounced taste for reading, he was able to communicate it to his son.

When he was about fourteen years old, a very happy event occurred in
Pierre's education. He was put under an excellent professor, A. Bazille,
who taught him elementary and advanced mathematics. This master was able
to appreciate his young pupil, became much attached to him, and directed
his work with the greatest solicitude. He even helped him to advance in
his study of Latin, in which he was very much behind. At the same time
Pierre and Albert Bazille, his professor's son, became friends.

This teaching had, I am sure, a great influence on the mind of Pierre,
aiding him to develop and to sound the depth of his faculties and to
realize his capacities for science. He had a remarkable aptitude for
mathematics, which expressed itself chiefly by a characteristic
geometric spirit and a great power of spatial vision. He, therefore,
progressed rapidly and joyfully in his studies under M. Bazille, for
whom he always felt an unalterable gratitude.

He once told me something which proved that even at this time he was not
content solely to follow a fixed program of studies, but that he had
already begun to launch out into personal investigation. Strongly
attracted by the theory of determinants, which he had just mastered, he
undertook to realize an analogous conception, but in three dimensions,
and endeavored to discover the properties and uses of these "cubical
determinants." Needless to say that at his age, and with the knowledge
then at his disposal, such an enterprise was beyond his powers. The
attempt, however, was none the less indicative of his awakening
inventive spirit.

Several years later, when preoccupied with reflections upon symmetry, he
asked himself the question: "Could not one find a general method for the
solution of any equation whatever? Everything is a question of
symmetry." He did not then know of Galois' theory of groups which had
made it possible to attack this problem. But he was happy later to learn
its results in the geometric applications to the case of equations of
the 5th degree.

Thanks to his rapid progress in mathematics and physics, Pierre Curie
was made a bachelor of science at the age of sixteen years. With this he
passed his most difficult stage of formal education. The only thing with
which he had to concern himself in the future was the acquisition of
knowledge through his personal and independent effort in a field of
science freely chosen.




CHAPTER II

DREAMS OF YOUTH. FIRST SCIENTIFIC WORK.
DISCOVERY OF PIEZO-ELECTRICITY


Pierre Curie was still very young when he began his higher studies in
preparation for the licentiate in physics. He followed the lectures and
laboratory work at the Sorbonne and had, besides, access to the
laboratory of Professor Leroux in the School of Pharmacy, where he
assisted in the preparation of the physics courses. At the same time he
became further acquainted with laboratory methods by working with his
brother Jacques, who was then preparator of chemistry courses under
Riche and Jungfleisch.

Pierre received his licentiate in physical sciences at the age of
eighteen. During his studies he had attracted the attention of Desains,
director of the University laboratory, and of Mouton, assistant director
of the same laboratory. Thanks to their appreciation he was appointed,
when only nineteen years old, preparator for Desains and placed in
charge of the students' laboratory work in physics. He held this
position five years, and it was during this time that he began his
experimental research.

It is to be regretted that because of his financial situation Pierre was
obliged, at this early age of nineteen, to accept the post of preparator
instead of being able to give his whole time for two or three years
longer to his University studies. With his time thus absorbed by his
professional duties and his investigations he had to give up following
the lectures in higher mathematics, and he therefore passed no further
examinations. In compensation, however, he was released from military
service in conformity with the privileges at that time accorded young
men who undertook to serve as teachers in the public-school system.

He was by this time a tall and slender young man with chestnut-colored
hair and a shy and reserved expression. At the same time his youthful
face mirrored a profound inner life. One has such an impression of him
as he appears in a good group photograph of Doctor Curie's family. His
head is resting on his hand in a pose of abstraction and reverie, and
one cannot but be struck by the expression of the large, limpid eyes
that seem to be following some inner vision. Beside him the brown-haired
brother offers a striking contrast, his vivacious eyes and whole
appearance suggesting decision.

The two brothers loved each other tenderly and lived as good comrades,
being accustomed to work together in the laboratory and walk together in
their free hours. They also kept up affectionate relations with a few of
their childhood friends: Louis Depouilly, their cousin, who became a
physician; Louis Vauthier, also later a physician; and Albert Bazille,
who became an engineer in the post and telegraph service.

Pierre used to tell me of the vivid memories he had of the vacations
passed at Draveil on the Seine, where, with his brother Jacques, he took
long walks beside the river, agreeably interrupted by swimming and
diving in the stream. Both brothers were excellent swimmers. Sometimes
they tramped for entire days. They had, at an early age, acquired the
habit of visiting the suburbs of Paris on foot. At times also Pierre
made solitary excursions which well suited his meditative spirit. On
these occasions he lost all sense of time, and went to the extreme limit
of his physical forces. Absorbed in delightful contemplation of the
things about him, he was not conscious of material difficulties.

On the pages of a diary written in 1879,[1] he thus expressed the
salutary influence of the country upon him:


"Oh, what a good time I have passed there in that gracious solitude, so
far from the thousand little worrying things that torment me in Paris.
No, I do not regret my nights passed in the woods, and my solitary days.
If I had the time I would let myself recount all my musings. I would
also describe my delicious valley, filled with the perfume of aromatic
plants, the beautiful mass of foliage, so fresh and so humid, that hung
over the Bièvre, the fairy palace with its colonnades of hops, the
stony hills, red with heather, where it was so good to be. Oh, I shall
remember always with gratitude the forest of the Minière; of all the
woods I have seen, it is this one that I have loved most and where I
have been happiest. Often in the evening I would start out and ascend
again this valley, and I would return with twenty ideas in my head."


Thus, for Pierre Curie, the sensation of well-being he experienced in
the country was derived from the opportunity for tranquil reflection.
Daily life in Paris with its numerous interruptions did not permit of
undisturbed concentration, and this was to him a cause of inquietude and
suffering. He felt himself destined for scientific research; for him the
necessity was imperative of comprehending the phenomena of Nature in
order to form a satisfactory theory to explain them. But when trying to
fix his mind on some problem he had frequently to turn aside because of
the multiplicity of futile things that disturbed his reflections and
plunged him into discouragement.

Under the heading, "A day like too many others," he enumerated in his
diary a list of the puerile happenings that had completely filled one of
his days, leaving no time for useful work. He then concluded: "There is
my day, and I have accomplished nothing. Why?" Further on he returns to
the same theme under a title borrowed from Victor Hugo's "Le Roi
S'Amuse,"


"To deafen with little bells the spirit that would think."


"In order that, weak one that I am, I shall not let my head turn with
all the winds, yielding to the least breath that touches it, it is
necessary that all should be immobile about me, or that, like a spinning
top, movement alone should render me insensible to external objects.

"When, in the process of turning slowly upon myself, I try to gain
momentum, a nothing, a word, a story, a paper, a visit stops me and is
able to put off or retard forever the moment when, granted a sufficient
swiftness I might have, in spite of my surroundings, concentrated on my
own intention.... We must eat, drink, sleep, be idle, love, touch the
sweetest things of life and yet not succumb to them. It is necessary
that, in doing all this, the higher thoughts to which one is dedicated
remain dominant and continue their unmoved course in our poor heads. It
is necessary to make a dream of life, and to make of a dream a reality."


This acute analysis, sufficiently surprising in a young man of twenty
years, suggests in an admirable manner the conditions necessary to the
highest manifestations of the intellect. It carries a lesson which, if
it were sufficiently understood, would facilitate the way of all
contemplative spirits capable of opening new paths for humanity.

The unity of thought toward which Pierre Curie strove was troubled not
only by professional and social obligations but also by his tastes,
which urged him towards a broad literary and artistic culture. Like his
father, he loved reading, and did not fear to undertake arduous literary
tasks. To some criticism made in this connection, he responded readily:
"I do not dislike tedious books." This meant that he was fascinated by
the search after truth which is sometimes associated with writing devoid
of charm. He also loved painting and music, and went gladly to look at
pictures or to attend a concert. A few fragments of poetry in his
handwriting were left among his papers.

But all these preoccupations were subordinated in his mind to what he
considered his true task, and when his scientific imagination was not in
full activity, he felt himself, in a sense, an incomplete being. He
expressed this inquietude with an emotion born of his suffering during
momentary periods of depression.


"What shall I become?" he wrote. "Very rarely have I command of all
myself; ordinarily a part of me sleeps. My poor spirit, are you then so
weak that you cannot control my body? Oh, my thoughts, you count indeed
for very little! I should have the greatest confidence in the power of
my imagination to pull me out of the rut, but I greatly fear that my
imagination is dead."


But despite hesitations, doubts, and lost moments, the young man was
little by little striking out his path and strengthening his will. He
was resolutely carrying on fruitful investigations at an age when many
men who were to become savants were as yet only pupils.

His first work, done in collaboration with Desains, concerned the
determination of the lengths of heat waves with the aid of a
thermoelectric element and a metallic wire grating, a process, then
entirely new, which has since often been employed in the study of this
question.

Following this he undertook an investigation on crystals in
collaboration with his brother, who had passed his licentiate and was
preparator for Friedel in the laboratory of mineralogy at the Sorbonne.
Their experiments led the two young physicists to a great success: the
discovery of the hitherto unknown phenomena of piezo-electricity, which
consists of an electric polarization produced by the compression or the
expansion of crystals in the direction of the axis of symmetry. This was
by no means a chance discovery. It was the result of much reflection on
the symmetry of crystalline matter, which enabled the brothers to
foresee the possibilities of such polarization. The first part of the
investigation was made in Friedel's laboratory. With an experimental
skill rare at their age, the young men succeeded in making a complete
study of the new phenomenon, established the conditions of symmetry
necessary to its production in crystals, and stated its remarkably
simple quantitative laws, as well as its absolute magnitude for certain
crystals. Several well-known scientists of other nations (Roentgen,
Kundt, Voigt, Riecke) have made further investigations along this new
road opened by Jacques and Pierre Curie.

The second part of the work, and much more difficult to realize
experimentally, concerned the compression resulting in piezo-electric
crystals when they are exposed to the action of an electric field. This
phenomenon, foreseen by Lippmann, was demonstrated by the Curie
brothers. The difficulty of the experiment lay in the minuteness of the
deformations that had to be observed. Fortunately Desains and Mouton
placed a small room adjoining the physics laboratory at the disposal of
the brothers so that they might proceed successfully with their delicate
operations.

From these researches, as much theoretical as experimental, they
immediately deduced a practical application, in the form of a new
apparatus, a piezo-electric quartz electrometer, which measures in
absolute terms small quantities of electricity, as well as electric
currents of low intensity. This apparatus has since then rendered great
service in experiments in radioactivity.[2]

During the course of their experiments on piezo-electricity the Curies
were obliged to employ electrometric apparatus, and, not being able to
use the quadrant electrometer known at that time, they developed a new
form of that instrument, better adapted to their necessities. This
became known in France as the Curie electrometer. Thus these years of
collaboration between the two brothers, always intimately united, proved
both happy and fruitful. Their devotion and their common interest in
science were to them both a stimulant and a support. During their work
the vivacity and energy of Jacques were of precious aid to Pierre,
always more easily absorbed by his thoughts.

However, this beautiful and close collaboration lasted only a few years.
In 1883, Pierre and Jacques were obliged to separate; Jacques left for
the University of Montpellier as Head Lecturer in Mineralogy (_Maître de
Conferences_). Pierre was made Director of Laboratory Work in the School
of Industrial Physics and Chemistry founded by the city of Paris at the
suggestion of Friedel and of Schützenberger, who became its first
director. Their remarkable researches with crystals won for the brothers
in 1895--very late, it is true--the Planté prize.


[Footnote 1: Pierre Curie did not leave a veritable diary but only a few
pages as chance permitted, covering but a short period of his life.]

[Footnote 2: The piezo-electric property of quartz has recently had an
important application; it has been utilized by P. Langevin in the
production of elastic waves of high frequency (beyond sound) sent out in
water with the aim of detecting submarine obstacles. This same method
can serve in a more general manner to explore ocean depths. We see,
here, once again, how pure speculation can lead to discoveries that will
be useful later in unforeseen directions.]




CHAPTER III

LIFE AS THE DIRECTOR OF LABORATORY WORK
IN THE SCHOOL OF PHYSICS AND CHEMISTRY.
GENERALIZATION OF THE PRINCIPLE
OF SYMMETRY. INVESTIGATIONS OF MAGNETISM


It was in the School of Physics, in the old buildings of the Collège
Rollin, that Pierre Curie was destined to work, first as Director of
Laboratory Work, then as Professor, for twenty-two years, a period
covering practically the whole of his scientific life. His memory seemed
to cling to these old buildings, now destroyed, in which he had passed
all his days, returning only in the evening to his parents in the
country. He counted himself fortunate since he enjoyed the favor of the
Founder-Director Schützenberger, and the esteem and good will of his
students, many of whom became his disciples and friends. In alluding to
this experience, at the close of an address delivered at the Sorbonne
near the end of his life, he said:


"I desire to recall here that we have made all our investigations in the
School of Physics and Chemistry of the city of Paris. In all creative
scientific work the influence of the surroundings in which one works is
of great importance, and a part of the result is due to that influence.
For more than twenty years I have worked in the School of Physics and
Chemistry. Schützenberger, the first director of the School, was an
eminent scientist. I remember with gratitude that he procured for me
opportunities for my own investigations when I was yet but an assistant.
Later, he permitted Madame Curie to work beside me, an authorization
which was at that time far from an ordinary innovation.

"Schützenberger allowed us all great liberty; his direction made itself
felt chiefly through his inspiring love of science. The professors of
the School of Physics and Chemistry, and the students who have gone from
it, have created a kindly and stimulating atmosphere that has been
extremely helpful to me. It is among the old students of the school that
we have found our collaborators and our friends. I am happy to be able,
here, to thank them all."


The newly appointed director of the laboratory was, when he first
assumed his duties, scarcely older than his students, who loved him
because of his extreme simplicity of manner, which was much more that of
a comrade than of a master. Some of these students recall with emotion
their work carried on with him and his discussion at the blackboard,
where he readily allowed himself to be led to debate scientific matters
to their great profit both in information and in kindled enthusiasm. At
a dinner given in 1903 by the Association of Former Students of the
School, which he attended, he laughingly recalled an incident of this
period. One day after lingering late with several students in the
laboratory, he found the door locked, and they all had to climb down
from the first floor single file, along a pipe that ran near one of the
windows.

Because of his reserve and shyness he did not make acquaintances easily,
but those whose work brought them near him loved him because of his
kindliness. This was true of his subordinates during his entire life. In
the school his laboratory helper, whom he had aided under trying
circumstances, thought of him with the greatest gratitude, in fact, with
veritable adoration.

Although separated from his brother, he remained bound to him by their
former bond of love and confidence. During vacations, Jacques Curie
would come to him that they might renew again that valuable
collaboration to which both willingly sacrificed their periods of
liberty. At times it was Pierre who joined Jacques, who was engaged in
making a geological chart of the Auvergne country, and there they
covered together the daily distances necessary to the tracing of such a
map.

Here are a few memories of these long walks, extracts from a letter
written to me shortly before our marriage:


"I have been very happy to pass a little time with my brother. We have
been far from all immediate care, and so isolated by our manner of
living that we have not even been able to receive a letter, never
knowing one night where we would sleep the next. At times it seemed to
me that we had gone back to the days when we lived entirely together.
Then we always arrived at the same opinions about all things, with the
result that it was no longer necessary for us to speak in order to
understand each other. This was all the more astonishing because we
differed so entirely in character."


From the point of view of scientific investigation, one must recognize
that the nomination of Pierre Curie to the School of Physics and
Chemistry retarded from the very first his experimental research.
Indeed, at the time of his appointment nothing yet existed in that
establishment; everything had to be created. Even the walls and the
partitions were hardly yet in place. He had, therefore, to organize
completely the laboratory and its work, and he acquitted himself of this
task in a remarkable manner, injecting into it the spirit of precision
and originality so characteristic of him.

The direction of the laboratory work of the large number of students
(thirty by promotion) was alone a strain on a young man, assisted as he
was only by one laboratory helper. The first years were, therefore, hard
years of assiduous work, of benefit chiefly to the students trained and
developed by the young laboratory director.

He himself profited by this enforced interruption of his experimental
research by trying to complete his scientific studies and, in
particular, his knowledge of mathematics. At the same time he became
engrossed in considerations of a theoretical nature on the relations
between crystallography and physics.

In 1884 he published a memoir on questions of the order and repetition
that are at the base of the study of the symmetry of crystals. This was
followed in the same year by a more general treatment of the same
subject. Another article on symmetry and its repetitions appeared in
1885. In that year he published, too, a very important theoretical
work[3] on the formation of crystals, and the capillary constants of
the different faces.

This rapid succession of investigations shows how completely engrossed
Pierre Curie was in the subject of the physics of crystals. Both his
theoretical and his experimental research in this domain grouped itself
around a very general principle, the principle of symmetry, that he had
arrived at step by step, and which he only definitely enunciated in
memoirs published between the years 1893 and 1895.

The following is the form, already classic, in which he made his
announcement:


"When certain causes produce certain effects, the elements of symmetry
in the causes ought to reappear in the effects produced.

"When certain effects reveal a certain dissymmetry, this dissymmetry
should be apparent in the causes which have given them birth.

"The converse of these two statements does not hold, at least
practically; that is to say, the effects produced can be more
symmetrical than their causes."


The capital importance of this statement, perfect in its simplicity,
lies in the fact that the elements of symmetry which it introduces are
related to all the phenomena of physics without exception.

Guided by an exhaustive study of the groups of symmetry which might
exist in nature, Pierre Curie showed how one should use this revelation
in character at once geometric and physical, in order to foresee whether
a particular phenomenon can reproduce itself, or whether its
reproduction is impossible under the given conditions. At the beginning
of a certain memoir, he insists in these terms:

"I think it is necessary to introduce into physics the ideas of symmetry
familiar to crystallographers."

His work in this field is fundamental, and even though he was led away
from it later by other investigations, he always retained a passionate
interest in the physics of crystals, as well as in projects of further
research in this domain.

The principle of symmetry to which Pierre Curie had so eagerly devoted
himself is one of the small number of great principles which dominate
the study of the phenomena of physics, and which, having their root in
ideas derived by experiment, yet little by little detach themselves and
assume a form more and more general and more and more perfect. It is in
this way that the idea of the equivalence of heat and of work, added to
the earlier notion of the equivalence of kinetic and potential energies,
brought about the establishment of the principle of the conservation of
energy whose application is entirely general. In the same way the law of
the conservation of mass grew out of the experiments of Lavoisier, which
belong to the foundations of chemistry. Recently an admirable synthesis
has made it possible for us to attain a still higher degree of
generalization through the union of these two principles, for it has
been proved that the mass of a body is proportional to its internal
energy. The study of electrical phenomena led Lippmann to announce the
general law of the conservation of electricity. The principle of Carnot,
born of considerations on the functioning of thermal machines, has
acquired also so general a significance, that it made possible the
foreseeing of the most probable character of spontaneous evolution for
all material systems.

The principle of symmetry furnishes an example of an analogous
evolution. To begin with, observation of Nature was able to suggest the
idea of symmetry; though such observations reveal only imperfectly any
regular dispositions in the aspects of animals and plants. The
regularity becomes very much more perfect in the case of crystallized
minerals. We may consider that Nature furnishes us the idea of a plane
of symmetry and of an axis of symmetry. An object possesses a plane of
symmetry, or a plane of reflection, if this plane divides the object
into two parts, of which each one may be thought of as the image of the
other reflected in the plane as in a mirror. It is this, approximately,
that occurs in the external appearance of man and of numerous animals.
An object possesses an axis of symmetry of the order _n_, if it
preserves the same appearance after a rotation on this axis of the nth
part of a revolution. Thus a regular flower of four petals has an axis
of symmetry of the order four, or a quarternary axis. Crystals like those
of rock salt or of alum possess many planes of symmetry and many axes of
symmetry of different orders.

Geometry teaches us to study the elements of symmetry of a limited
figure such, for instance, as a polyhedron; and to discover the
relations between its parts which permit us to reunite different
symmetries in groups. The knowledge of these groups is of the greatest
usefulness in establishing a rational classification of crystal forms in
a small number of systems each of which is derived from a simple
geometric form. Thus the regular octahedron belongs to the same system
as the cube, for in the case of each the group formed by the axes and
the planes of symmetry is the same.

In the study of the physical properties of crystalline matter it is
necessary to take account of the symmetry of such matter. This is, in
general, _anisotropic_; that is to say, it has not the same properties
in all directions. On the other hand, media such as glass or water are
isotropic, having equivalent properties in all directions. It was the
study of optics which first showed that the propagation of light in a
crystal is dependent upon the elements of symmetry in that crystal. The
same thing is true for the conduction of heat or electricity, for
magnetization, for polarization, etc.

It was in reflecting upon the relations between cause and effect that
govern these phenomena that Pierre Curie was led to complete and extend
the idea of symmetry, by considering it as a condition of space
characteristic of the medium in which a given phenomenon occurs. To
define this condition it is necessary to consider not only the
constitution of the medium but also its condition of movement and the
physical agents to which it is subordinated. Thus a right circular
cylinder possesses a plane of symmetry perpendicular to its axis in its
position, and an infinity of planes of symmetry pass through its axis.
If the same cylinder is in rotation on its axis, the first plane of
symmetry persists, but all the others are suppressed. Furthermore, if an
electric current traverses the cylinder lengthwise, no plane of symmetry
remains.

In every phenomenon the elements of symmetry compatible with its
existence may be determined. Certain elements can coexist with certain
phenomena, but they are not necessary to them. That which is necessary
is that certain ones among these elements shall not exist. It is
_dissymmetry_ that creates the phenomenon. When several phenomena are
superposed in the same system, the dissymmetries are added together.
"Works of Pierre Curie," page 127.

It was from the above considerations that Pierre Curie announced the
general law whose text, already cited, attains the highest degree of
generalization. The synthesis thus obtained seems complete, and all that
was further needed was to deduce from it all the developments of which
it admits.

For this it is convenient to define the particular symmetry of each
phenomenon and to introduce a classification which makes clear the
principal groups of symmetry. Mass, electric charge, temperature, have
the same symmetry, of a type called _scalar_, that of the sphere. A
current of water and a rectilineal electric current have the symmetry of
an arrow, of the type _polar vector_. The symmetry of an upright
circular cylinder is of the type _tensor_. All of the physics of
crystals can be expressed in a form in which the particular phenomena in
question are not specified, but in which are examined only the
geometrical and analytical relations between the types of quantities
where certain ones are considered as causes and the other as effects.

Thus, the study of electrical polarization by the application of an
electric field becomes the examination of the relation between two
systems of vectors, and the writing out of a system of linear equations
having 9 coefficients. The same system of equations holds for the
relation between an electric field and an electric current in
crystalline conductors; or for that between the temperature gradient and
the heat current, except that the meaning of the coefficients must be
changed. Similarly, a study of the general relations between a vector
and a system of tensors can reveal all the characteristics of
piezo-electric phenomena. And all the rich variety of the phenomena of
elasticity depends on the relation between two sets of tensors which
require, in principle, 36 coefficients.

The foregoing brief exposition reveals the high philosophic import of
these conceptions of symmetry which touch all natural phenomena, and
whose profound significance Pierre Curie so clearly set forth. It is
interesting in this connection to recall the relation which Pasteur saw
between these same conceptions and the manifestations of life. "The
universe," he said, "is a dissymmetric whole. I am led to believe that
life, as it is revealed to us, must be a function of the dissymmetry of
the universe, or of the consequences that it involves."

As his organization of his work in the School progressed, Pierre Curie
could begin to dream of going forward again with his experimental
research. He could do so, however, only under most precarious
conditions, for he had not even a laboratory for his personal work, nor
a room of any kind entirely at his disposition. Besides, he possessed no
funds to support his investigations. It was only after he had been
several years at the School that he obtained, thanks to the influence of
Schützenberger, a small annual subvention for his work. Up to that time
the materials necessary for him were provided, thanks to the kindness of
his superiors, to the extent possible, by drawing upon a very limited
general fund of the teaching laboratory. As for a place to work in, he
had to content himself with very little. He set up certain of his
experiments in the rooms of his pupils when these were not in use. But
more frequently he worked in an outside corridor running between a
stairway and a laboratory. It was there that he conducted, in
particular, his long research on magnetism.

This abnormal state of affairs was manifestly prejudicial to his work,
but it had, nevertheless, the happy result of bringing his students
closer to him, for it allowed them, at times, to share in his personal
scientific interests.

His return to experimental research is marked by a profound study of the
"direct reading periodic precision balance for least weights." (1889,
1890, 1891.) In this balance, the use of small weights is suppressed by
the employment of a microscope by means of which one reads a micrometer
attached to the extremity of one of the arms of the balance. The reading
is made when the oscillation of the balance is arrested, which can occur
very rapidly, thanks to the use of pneumatic dampeners conveniently
constructed. This balance marks a considerable advance over old systems.
It has shown itself particularly valuable in laboratories for chemical
analysis, where the rapidity of the weighings is frequently a test of
precision. We can say that the introduction of the Curie balances marks
an epoch in the construction of these instruments. The work done in this
field was far from empirical; it comprised a study of the theory of
damped movements and the construction of numerous curves established
with the aid of some of his students.

It was toward 1891 that Pierre Curie began a long series of
investigations on the magnetic properties of bodies at divers
temperatures, from the normal up to 1400° C. These investigations,
covering years, were presented as a Doctor's thesis before the Faculty
of Sciences of the University of Paris in 1895. In it he stated
precisely in the following few words the object and results of his work:


"From the point of view of their magnetic properties, bodies may be
divided into two groups: _diamagnetic_ bodies, bodies only feebly
magnetic, and _paramagnetic_ bodies.[4] At first sight the two groups
seem entirely separate. The principal aim of this research has been to
discover if there exist transitions between these two states of matter,
and if it is possible to make a given body pass progressively through
them. To determine this I have examined the properties of a great number
of bodies at temperatures differing as much as possible, in magnetic
fields of varying intensities.

"My experiments failed to prove any relation between the properties of
_diamagnetic_ and those of _paramagnetic_ bodies. _And the results
support the theories which attribute magnetism and diamagnetism to
causes of a different nature_. On the contrary, the properties of
_ferro-magnetic_ bodies and of bodies _feebly magnetic_ are intimately
united."


This experimental work presented many difficulties, for it necessitated
the measuring of very minute forces (of the order of ¹⁄₁₀₀ of a
milligramme weight) within a container where the temperature could
attain 400° C.

As Pierre Curie well understood, the results he obtained are, from a
theoretic point of view, of fundamental importance. The Curie law,
according to which the coefficient of magnetization of a body feebly
magnetized varies in inverse ratio to the absolute temperature, is a
remarkably simple law. It is quite comparable to the Gay-Lussac law
relating to the variation of the density of a perfect gas with the
temperature. In his well known theory of magnetism P. Langevin, in 1905,
took into account the Curie law and arrived again, theoretically, at the
difference between the origins of diamagnetism and paramagnetism. His
work, as well as the important investigations of P. Weiss, demonstrated
the accuracy of Pierre Curie's conclusions, as well as the importance of
the analogy that he perceived between the intensity of magnetization and
the density of a fluid--the paramagnetic state being comparable to a
gaseous state, and the ferro-magnetic state to the state of
condensation.

In connection with this work, Pierre Curie spent some time in the search
for unknown phenomena whose existence did not seem, _a priori_,
impossible to him. He sought for bodies strongly diamagnetic, but found
none. He tried to discover, too, if there were bodies that acted as
conductors of magnetism, and if magnetism can exist in a "free state,"
like electricity. Here also the result was negative. He never published
any of these investigations, for he had the habit of thus engaging in
the pursuit of phenomena, often with little hope of success, solely for
the love of the unforeseen, and without ever thinking of publication.

Because of this entirely disinterested passion for scientific research
the presentation of a doctor's thesis which would give an account of
these early investigations had never appealed to him. He was already
thirty-five years old when he decided to gather together, in such a
thesis, the results of his beautiful work on magnetism.

I have a very vivid memory of how he sustained his thesis before the
examiners, for he had invited me, because of the friendship that already
existed between us, to be present on the occasion. The jury was composed
of Professors Bonty, Lippmann, and Hautefeuille. In the audience were
some of his friends, among them his aged father, extremely happy in his
son's success. I remember the simplicity and the clarity of the
exposition, the esteem indicated by the attitude of the professors, and
the conversation between them and the candidate which reminded one of a
meeting of the Physics Society. I was greatly impressed; it seemed to me
that the little room that day sheltered the exaltation of human thought.

In recalling this period in the life of Pierre Curie, between 1883 and
1895, we can appreciate the great progress the young physicist had made
while acting as Chief of Laboratory. He had succeeded during this time
in organizing an entirely new teaching service; he had published an
important series of theoretical memoirs, as well as the results of
experimental research of the first order. In addition, he had
constructed new apparatus of great perfection--and all this in spite of
very insufficient accommodations and resources. This achievement
suggests the distance he had traveled since the doubts and hesitations
of his early youth in learning to discipline his methods of work, and to
derive from them the full advantage of his exceptional capacities.

He enjoyed a growing esteem in France, and in foreign countries. He was
listened to with interest at the meetings of the learned societies
(Society of Physics, Society of Mineralogy, Society of Electricians),
where he was in the habit of presenting his communications and where he
joined readily in the discussion of various scientific questions.

Among foreign scholars who already at this time appreciated him highly,
I can name, in the first place, the illustrious English physicist, Lord
Kelvin, who joined with him in a certain scientific discussion, and who
often expressed for him, from that time on, both esteem and sympathy.
During one of his visits to Paris, Lord Kelvin was present at a meeting
of the Society of Physics when Pierre Curie made a statement regarding
the construction and the use of standard condensers with guard ring. In
this statement he recommended the use of an apparatus which involved the
charging of the central part of the guard ring plate by a galvanic cell
and in uniting the guard ring with the earth. One uses then, as a
measure, the charge induced on the second plate. Even though the
resulting disposition of lines of the field be complex, the charge
induced can be calculated by a theorem of electrostatics, with the same
simple formula as is used for an ordinary apparatus in a uniform field,
and one has the benefit of a better isolation. Lord Kelvin believed at
first that this reasoning was inexact. Despite his great repute and his
advanced age, he went the following day to the laboratory to find the
young Director. Here he discussed the matter with him before the
blackboard. He was completely convinced, and seemed even delighted to
concede the point to his companion.[5]

It may seem astonishing that Pierre Curie, in spite of his merits,
continued during twelve years in the small position of Chief of
Laboratory. Without doubt this was largely due to the fact that it is
easy to overlook those who have not the active support of influential
persons. It was due also to the fact that it was impossible for him to
take the many steps that the pushing of any candidature involves. Then,
too, his independence of character ill fitted him to ask for an advance,
and this notwithstanding the fact that his position was very modest.
Indeed his salary, then comparable to that of a day laborer (about 300
francs a month), was scarcely sufficient to enable him to lead the
simple life that would yet permit him to carry on his work.

He expressed his feelings on this subject in the following words:


"I have heard that perhaps one of the professors will resign, and that I
might, in that case, make application to succeed him. What an ugly
necessity is this of seeking any position whatsoever; I am not
accustomed to this form of activity, demoralizing to the highest degree.
I am sorry that I spoke to you about it. I think that nothing is more
unhealthy to the spirit than to allow oneself to be occupied by things
of this character and to listen to the petty gossip that people come to
report to you."


If he disliked soliciting an advancement in position, he was even less
inclined to hope for honors. He had, in fact, a very decided opinion on
the subject of honorary distinctions. Not only did he believe that they
were not helpful, but he considered them frankly harmful. He felt that
the desire to obtain them is a cause of trouble, and that it can degrade
the worthiest aim of man, which is, work for the pure love of it.

Since he possessed great moral probity, he did not hesitate to make his
acts conform to his opinions. When Schützenberger, in order to offer
him a mark of esteem, wished to propose him for the _Palmes
académiques_ he refused this distinction, despite the advantages which,
according to general belief, it would confer. And he wrote to his
director:


"I have been informed that you intend to propose me again to the
_prefet_ for the decoration. I pray you do not do so. If you procure for
me this honor, you will place me under the necessity of refusing it, for
I have firmly decided not to accept a decoration of any kind. I hope
that you will be good enough to avoid taking a step that will make me
appear a little ridiculous in the eyes of many people. If your aim is to
offer me a testimony of your interest, you have already done that, and
in a very much more effective manner which touched me greatly, for you
have made it possible for me to work without worry."


Faithful to this firm opinion, he later declined the decoration of the
Légion d'Honneur, which was offered him in 1903.

But even though Pierre Curie refused to take steps to change his
situation it was at last improved. In 1895 the well-known physicist,
Mascart, professor in the Collège de France, impressed with his
ability, and with Lord Kelvin's opinion of him, insisted that
Schützenberger create a new Chair of Physics at the School of Physics
and Chemistry. Pierre Curie was then named professor under conditions in
which his talents were duly recognized. However, nothing was done at
this time to ameliorate the inadequate material conditions under which,
as we have already seen, he was carrying on his personal investigations.


[Footnote 3: In this very brief memoir is presented, for the first time,
a theory which explains why crystals develop certain faces
simultaneously, in a particular direction, and consequently why crystals
possess a determined form.]

[Footnote 4: _Paramagnetic_ bodies are those which are magnetized in the
same manner as iron, either strongly (_ferro-magnetic_) or feebly.
_Diamagnetic_ bodies are those whose very feeble magnetization is
opposed to that which iron takes in the same magnetic field.]

[Footnote 5: The following is the text of a letter from this
distinguished savant to Pierre Curie, written during one of his visits
to Paris:

                   October, 1893.

"DEAR MR. CURIE:

"I am much obliged to you for your letter of Saturday and the
information contained in it, which is exceedingly interesting to me.

"If I call at your laboratory between 10 and 11 tomorrow morning should
I find you there? There are two or three things I would like to speak to
you about; and I would like also to see more of your curves representing
the magnetization of iron at different temperatures.

                  "Yours truly,

                            "KELVIN."]




CHAPTER IV

MARRIAGE AND ORGANIZATION OF THE FAMILY
LIFE. PERSONALITY AND CHARACTER


I met Pierre Curie for the first time in the spring of the year 1894. I
was then living in Paris where for three years I[6] had been studying at
the Sorbonne. I had passed the examinations for the licentiate in
physics, and was preparing for those in mathematics. At the same time I
had begun to work in the research laboratory of Professor Lippmann. A
Polish physicist whom I knew, and who was a great admirer of Pierre
Curie, one day invited us together to spend the evening with himself and
his wife.

As I entered the room, Pierre Curie was standing in the recess of a
French window opening on a balcony. He seemed to me very young, though
he was at that time thirty-five years old. I was struck by the open
expression of his face and by the slight suggestion of detachment in his
whole attitude. His speech, rather slow and deliberate, his simplicity,
and his smile, at once grave and youthful, inspired confidence. We began
a conversation which soon became friendly. It first concerned certain
scientific matters about which I was very glad to be able to ask his
opinion. Then we discussed certain social and humanitarian subjects
which interested us both. There was, between his conceptions and mine,
despite the difference between our native countries, a surprising
kinship, no doubt attributable to a certain likeness in the moral
atmosphere in which we were both raised by our families.

We met again at the Physics Society and in the laboratory. Then he asked
if he might call upon me. I lived at that time in a room on the sixth
floor of a house situated near the schools. It was a poor little room,
for my resources were extremely limited. I was, nevertheless, very happy
in it for I was now first realizing, although already twenty-five years
old, the ardent desire I had so long cherished of carrying on advanced
studies in science.

Pierre Curie came to see me, and showed a simple and sincere sympathy
with my student life. Soon he caught the habit of speaking to me of his
dream of an existence consecrated entirely to scientific research, and
he asked me to share that life. It was not, however, easy for me to make
such a decision, for it meant separation from my country and my family,
and the renouncement of certain social projects that were dear to me.
Having grown up in an atmosphere of patriotism kept alive by the
oppression of Poland, I wished, like many other young people of my
country, to contribute my effort toward the conservation of our national
spirit.

So matters stood, when at the beginning of my vacation I left Paris to
go to my father in Poland. Our correspondence during this separation
helped to strengthen the bond of affection between us.

During the year 1894 Pierre Curie wrote me letters that seem to me
admirable in their form. No one of them was very long, for he had the
habit of concise expression, but all were written in a spirit of
sincerity and with an evident anxiety to make the one he desired as a
companion know him as he was. The very quality of the expression has
always seemed to me remarkable. No other one could describe in a few
lines, as he could, a state of mind, or a situation, and by the simplest
means make that description evoke a seizing image of truth. Because of
this gift, he might, I believe, have been a great writer. I have already
cited a few fragments of his letters, and others will follow. It is
appropriate to quote here a few lines which express how he looked on the
possibility of our marriage:


"We have promised each other (is it not true?) to have, the one for the
other, at least a great affection. Provided that you do not change your
mind! For there are no promises which hold; these are things that do not
admit of compulsion.

"It would, nevertheless, be a beautiful thing in which I hardly dare
believe, to pass through life together hypnotized in our dreams: your
dream for your country; our dream for humanity; our dream for science.
Of all these dreams, I believe the last, alone, is legitimate. I mean to
say by this that we are powerless to change the social order. Even if
this were not true we should not know what to do. And in working without
understanding we should never be sure that we were not doing more harm
than good, by retarding some inevitable evolution. From the point of
view of science, on the contrary, we can pretend to accomplish
something. The territory here is more solid and obvious, and however
small it is, it is truly in our possession.

"I strongly advise you to return to Paris in October. I shall be very
unhappy if you do not come this year, but it is not my friend's
selfishness that makes me ask you to return. I ask it because I believe
you will work better here and that you can accomplish here something
more substantial and more useful."


One can understand, from this letter, that for Pierre Curie there was
only one way of looking at the future. He had dedicated his life to his
dream of science: he felt the need of a companion who could live his
dream with him. He told me many times that the reason he had not married
until he was thirty-six was because he did not believe in the
possibility of a marriage which would meet this, his absolute necessity.

When he was twenty-two years old he wrote in his diary:


"Women, much more than men, love life for life's sake. Women of genius
are rare. And when, pushed by some mystic love, we wish to enter into a
life opposed to nature, when we give all our thoughts to some work which
removes us from those immediately about us, it is with women that we
have to struggle, and the struggle is nearly always an unequal one. For
in the name of life and of nature they seek to lead us back."


We can see, however, in the letters I have quoted earlier, the
unshakeable faith that Pierre Curie had in science and in its power to
further the general good of humanity. It seems appropriate to apply to
him the sentiment expressed by Pasteur in words so well known: "I
believe invincibly that science and peace will triumph over ignorance
and war."

This confidence in the solutions of science made Pierre Curie little
inclined to take an active part in politics. He was attached, by
education and by conviction, to democratic and socialistic ideas, but he
was not dominated by any party doctrine. However, he always fulfilled,
as his father did, his obligations as a voter. In public life, as in
private life, he was opposed to the use of violence.


"What would you think," he wrote me, "of a person who would knock his
head against a stone wall with the intention of overthrowing it? Such an
idea might be the result of very beautiful feelings, but in realization
it would be ridiculous and stupid. I believe that certain questions
demand a general solution, and do not admit, today, of specific
solutions, and that one who begins a course that has no issue, may do
much harm. I believe, further, that justice is not of this world, and
that the strongest system or rather the one best developed from the
economic point of view will be that which will stand. A man may exhaust
himself by work, and yet live, at best, miserably. This is a revolting
fact, but it will not, because of that, cease. It will disappear
probably because man is a kind of machine, and it is of economic
advantage to make every machine work in its normal manner, without
forcing it."


He felt the same necessity for clarity and understanding in considering
his own inner life as in examining a general problem. A great necessity
of loyalty to himself and toward others made him suffer from the
compromises imposed by life, even though he reduced them to a minimum.


"We are all the slaves of our affections," he wrote, "slaves of the
prejudices of those we love. Besides, we must make a living, and this
forces us to become a wheel in the machine. The most painful are the
concessions we are forced to make to the prejudices of the society in
which we live. We must make more or fewer compromises according as we
feel ourselves feebler or stronger. If one does not make enough
concessions he is crushed; if he makes too many he is ignoble and
despises himself. I find myself far from the principles I held ten years
ago. At that time I believed it necessary to be excessive in everything,
and to make no concessions whatsoever to one's environment. I believed
it necessary to exaggerate one's faults as well as one's virtues."


This was the _credo_ of the man who, without fortune himself, desired to
share his life with that of a student also without fortune, whom he had
met by chance.

After my return from my vacation our friendship grew more and more
precious to us; each realized that he or she could find no better life
companion. We decided, therefore, to marry, and the ceremony took place
in July, 1895. In conformity with our mutual wish it was the simplest
service possible,--a civil ceremony, for Pierre Curie professed no
religion, and I myself did not practice any. My husband's parents
received me with great cordiality, and reciprocally my father and my
sisters, who were present at our marriage, were happy in knowing the
family to which I was to belong.

Our first home, an extremely simple one, consisted of a little apartment
of three rooms in the rue de la Glacière, not far from the School of
Physics. Its chief attraction was its view of a large garden. It was
furnished very simply with objects that had belonged to our families.
Our means did not permit our having servants, so that I had to assume
practically all the household duties, as I had been in the habit of
doing during my student days.

Professor Curie's salary was 6000 francs a year, and we held that he
should not undertake any supplementary work, at least in the beginning.
As for myself, I was preparing to take the examination for the
_agregation_ of young women, in view of obtaining a teaching post. These
I passed in 1896. We ordered our life to suit our scientific work and
our days were passed in the laboratory, where Schützenberger permitted
that I might work with my husband.

He was then engaged in a research on the growth of crystals, which
interested him keenly. He wished to know if certain faces of a crystal
had a preferential development chiefly because they have a different
rapidity of growth or because their solubility is different. He quickly
obtained interesting results (not published) but he had to interrupt his
investigations to undertake others on radioactivity. And he often
regretted that he was never able to return to them. I was occupied at
this time with the study of the magnetization of tempered steel.

The preparation of his class lectures was for Pierre Curie a genuine
care. The Chair was a new one, and carried no prescribed course of
study. He divided his lectures, at first, between crystallography and
electricity. Then, as he recognized more and more the utility of a
serious theoretical course in electricity for future engineers, he
devoted himself entirely to this subject, and succeeded in establishing
a course (of about 120 lectures) that was the most complete and modern
then to be had in Paris. This cost him a considerable effort, of which I
was the daily witness; for he was always anxious to give a complete
picture of the phenomena and of the evolution of theories, and of ideas.
He was always anxious, too, that his mode of exposition should be clear
and precise. He thought of publishing a treatise summing up this course,
but unfortunately the many preoccupations of the following years
prevented him from putting this plan into execution.

We lived a very single life, interested in common, as we were, in our
laboratory experiments and in the preparation of lectures and
examinations. During eleven years we were scarcely ever separated, which
means that there are very few lines of existing correspondence between
us, representing that period. We spent our rest days and our vacations
walking or bicycling either in the country near Paris, or along the sea,
or in the mountains. My husband was so engrossed in his researches,
however, that it was very difficult for him to remain for any length of
time in a place where he lacked facilities for work. After a few days he
would say: "It seems to me a very long time since we have accomplished
anything." And yet he liked the excursions which covered successive
days, and enjoyed to the full our walks together, just as he had
formerly enjoyed those with his brother. But his joy in seeing beautiful
things never drew his thoughts away from the scientific questions that
absorbed him. In these free times, we traversed the region of the
Cevennes and of the Monts d'Auvergne, as well as the coast of France,
and some of its great forests.

These days in the open, filled with beautiful sights, made a deep
impression on us, and we loved to recall them. One of our radiant
memories was of a sunny day, when after a long and wearying climb, we
reached the fresh, green meadow of the Aubrac, in the pure air of the
high plateaus. Another vivid memory was that of an evening, when,
lingering until twilight in the gorge of the Truyère, we were enchanted
to hear a popular air dying away in the distance, carried to us from a
little boat that descended the stream. We had taken so little notice of
the time that we did not regain our lodging before dawn. At one point we
had an encounter with carts whose horses were frightened by our
bicycles, and we were obliged to cut across ploughed fields. At length
we regained our route on the high plateau, bathed in the unreal light of
the moon. And cows that were passing the night in enclosures came
gravely to contemplate us with their large, tranquil eyes.

The forest of Compiegne charmed us in the spring, with its mass of green
foliage stretching far as the eye could see, and its periwinkles and
anemones. On the border of the forest of Fontainebleau, the banks of the
Loing, covered with water buttercups, were an object of delight for
Pierre Curie. We loved the melancholy coasts of Brittany and the reaches
of heather and gorse, stretching to the very points of Finistère, which
seemed like claws or teeth burying themselves in the water which forever
rages at them.

Later, when we had our baby with us, we passed our vacations in some one
locality, without traveling about. We lived then as simply as possible
in retired villages where we could scarcely be distinguished from the
villagers themselves. I remember the stupefaction of an American
journalist when he found us one day at Pouldu, at a moment when I was
sitting on one of the stone steps of our house in the act of shaking the
sand from my sandals. However, his embarrassment was short-lived and,
adapting himself to the situation, he sat down beside me and began
jotting down in his notebook my answers to his questions.

The most affectionate relations existed between my husband's parents and
myself. We often went to Sceaux, where the room my husband used to have
before our marriage was always reserved for us. I had also a very tender
affection for Jacques Curie and his family (he was married and had two
children); for Pierre's brother became mine, and has always remained so.

Our eldest daughter, Irene, was born in September, 1897, and only a few
days afterwards my husband suffered a great loss in the death of his
mother. Doctor Curie came to live with us in a house which had a garden
and was situated on the old fortifications of Paris (108 Boulevard
Kellermann) near the park of Montsouris. Pierre Curie lived in this
house until the end of his life.

With the birth of our child, the difficulties of carrying on our work
were augmented: for I had to give more time to the household. Very
fortunately for us I could leave my little girl with her grandfather,
who much enjoyed taking care of her. But we had to think also of
increasing our resources to meet the needs of our larger family and to
enable us to secure someone to help me in the house, a necessity from
now on. However, our situation remained as it was during the following
two years, which we consecrated to intensive laboratory research on
radioactivity. It was, indeed, not relieved until 1900, to the
detriment, it is true, of the amount of time we could give to our
investigations.

All formal social obligations were excluded from our life. Pierre Curie
had for such things an unconquerable repugnance. Neither in his earlier
nor his later life would he pay visits or undertake to involve himself
in relations without special interest. By nature grave and silent, he
preferred to abandon himself to his own reflections, rather than to
engage in an exchange of banal words. On the other hand, he valued
greatly his boyhood friends, and those to whom he was bound by a common
interest in science.

Among the latter, E. Gouy, professor of the faculty of sciences at Lyon,
should be named. His friendly relations with Pierre Curie dated from the
time when they were both preparators at the Sorbonne. They carried on
regularly a scientific correspondence, and took great pleasure in seeing
each other again during the various brief visits of E. Gouy to Paris, on
which occasions they were inseparable. There existed also a friendship
of long standing between my husband and Ch. Ed. Guillaume, now director
of the International Bureau of Weights and Measures of Sèvres. They met
at the Physics Society and occasionally on Sundays at Sèvres or Sceaux.
Later a group of younger men formed themselves about Pierre Curie. They
were investigators engaged, as he was, in physical and chemical research
in the newest fields of these sciences. Among these men were André
Debierne, my husband's intimate friend and collaborator in the work on
radioactivity; George Sagnac, his collaborator in a study of the X-rays;
Paul Langevin, who became a professor in the Collège de France; Jean
Perrin, at present professor of physical chemistry in the Sorbonne; and
Georges Urbain, student of the School of Physics and later professor in
the Sorbonne. Often one or the other came to see us in our quiet house
in the Boulevard Kellermann. Then we engaged in discussions of recent or
future experiments, or of new ideas and theories, and never tired of
rejoicing over the marvelous development of modern physics.

There were not many large reunions in our house, for my husband did not
feel the need of them. He was more at his ease in a conversation with
some one or few persons, and rarely attended any meetings except those
of the scientific societies. If by chance he found himself in a
gathering where the general conversation did not interest him, he took
refuge in a tranquil corner where he could forget the company as he
pursued his own thoughts.

Our relations with our families were very restricted on his side as on
mine; for he had few relatives and mine were far away. He was, however,
very devoted to those of my family who could come to visit me in Paris,
or during our vacations.

In 1899, Pierre Curie made a journey with me to the Carpathians of
Austrian Poland, where one of my sisters, married to Doctor Dluski and
herself a physician, directed, with him, a large sanatorium. Through a
touching desire to know all that was dear to me, my husband, though he
knew little of foreign languages, wished to learn Polish, something
which I had not thought of suggesting because I did not believe it could
prove sufficiently useful to him. He felt a sincere sympathy for my
country and believed in the future Establishment of a free Poland.

In our life together it was given to me to know him as he had hoped I
might, and to penetrate each day further into his thought. He was as
much and much more than all I had dreamed at the time of our union. My
admiration of his unusual qualities grew continually; he lived on a
plane so rare and so elevated that he sometimes seemed to me a being
unique in his freedom from all vanity and from the littlenesses that one
discovers in oneself and in others, and which one judges with indulgence
although aspiring to a more perfect ideal.

In this lay, without doubt, the secret of that infinite charm of his to
which one could not long rest insensible. His thoughtful expression and
the directness of his look were strongly attractive and this attraction
was increased by his kindliness and gentleness of character. He
sometimes said that he never felt combative, and this was entirely true.
One could not enter into a dispute with him because he could not become
angry. "Getting angry is not one of my strong points," he would say,
smiling. If he had few friends, he had no enemies; for he could not
injure anyone, even by inadvertence. But at the same time no one could
force him to deviate from his line of action, something which led his
father to nickname him the "gentle stubborn one."

When he expressed his opinion he did so frankly, for he was convinced
that diplomatic methods are puerile, and that directness is at once
easiest and best. Because of this practice, he acquired a certain
reputation for naïveté; in reality he was acting on a well-considered
decision, rather than by instinct. It was perhaps because he was able to
judge himself and to retire within himself, that he was so capable of
clearly appreciating the springs of action, the intention, and the
thoughts of others. And if he sometimes neglected details, he was rarely
deceived in the essentials. Usually he kept his sure judgments to
himself; but once he had made up his mind he sometimes expressed them
without reticence, in the assurance that he was doing something useful.

In his scientific relations he showed no sharpness, and did not permit
himself to be influenced by considerations of personal credit or by
personal sentiments. Every beautiful success gave him pleasure, even if
achieved in a domain where he felt himself to have priority. He said:
"What does it matter if I have not published such and such
investigations, if another has published them?" For he held that in
science we should be interested in things and not in persons. He was so
genuinely against every form of emulation that he opposed even the
competitions and gradings of the lycées, as well as all forms of
honorary distinction. He never failed to give counsel and encouragement
to any of those who showed an aptitude for science, and certain among
them still remain profoundly grateful to him.

If his attitude was that of one of the élite who have attained the
highest summit of civilization, his acts were those of a truly good man
endowed with the sentiment of human solidarity intimately bound to his
intellectual conceptions, and full of understanding and indulgence. He
was always ready to aid, as far as his means allowed, any person in a
difficult situation, even if helping meant giving some of his time,
which was always the greatest sacrifice he could make. His generosity
was so spontaneous that one scarcely noticed it. He believed that the
only advantage of material means, beyond that of providing the
necessities of a simple life, was in the opportunity they offered of
aiding others, and of pursuing the work of one's preference.

What shall I say, finally, of his love for his own, and of his qualities
as friend? His friendship, which he gave rarely, was sure and faithful,
for it rested on a community of ideas and opinions. And still more
rarely did he give affection; but how complete was his gift to his
brother and to me! He could forsake his customary reserve for an
unconstraint which established harmony and confidence. His tenderness
was the most exquisite of blessings, sure and helpful, full of
gentleness and solicitude. It was good to be surrounded by this
tenderness; it was cruel to lose it after having lived in an atmosphere
completely permeated by it. But I will let his own words tell how
completely he gave himself:


"I think of you who fill my life, and I long for new powers. It seems to
me that in concentrating my mind exclusively upon you, as I am doing,
that I should succeed in seeing you, and in following what you are
doing; and that I should be able to make you feel that I am altogether
yours at this moment,--but the image does not come."


We were not warranted in having great confidence in our health, nor in
our strength so often put to severe tests. And from time to time, as
happens to those who know the value of sharing a common life, the fear
of the irreparable touched our minds. In such moments his simple courage
led him always to the same inevitable conclusion: "Whatever happens,
even if one should become like a body without a soul, still one must
always work."


[Footnote 6: The following are a few brief biographical details:

My name is Marie Sklodowska. My father and mother belonged to Catholic
Polish families. Both were teachers in secondary schools in Warsaw (at
that time under Russia). I was born in Warsaw and attended a lycée
there. Following the lycée, I taught several years. Then in 1892 I came
to Paris in order to study science.]




CHAPTER V

THE DREAM BECOME A REALITY. THE DISCOVERY OF RADIUM


I have already said that in 1897 Pierre Curie was occupied with an
investigation on the growth of crystals. I myself had finished, by the
beginning of vacation, a study of the magnetization of tempered steels
which had resulted in our getting a small subvention from the Society
for the Encouragement of National Industry. Our daughter Irene was born
in September, and as soon as I was well again, I resumed my work in the
laboratory with the intention of preparing a doctor's thesis.

Our attention was caught by a curious phenomenon discovered in 1896 by
Henri Becquerel. The discovery of the X-ray by Roentgen had excited the
imagination, and many physicians were trying to discover if similar rays
were not emitted by fluorescent bodies under the action of light. With
this question in mind Henri Becquerel was studying uranium salts, and,
as sometimes occurs, came upon a phenomenon different from that he was
looking for: the spontaneous emission by uranium salts of rays of a
peculiar character. This was the discovery of radioactivity.

The particular phenomenon discovered by Becquerel was as follows:
uranium compound placed upon a photographic plate covered with black
paper produces on that plate an impression analogous to that which light
would make. The impression is due to uranium rays that traverse the
paper. These same rays can, like X-rays, discharge an electroscope, by
making the air which surrounds it a conductor.

Henri Becquerel assured himself that these properties do not depend on a
preliminary isolation, and that they persist when the uranium compound
is kept in darkness during several months. The next step was to ask
whence came this energy, of minute quantity, it is true, but constantly
given off by uranium compounds under the form of radiations.

The study of this phenomenon seemed to us very attractive and all the
more so because the question was entirely new and nothing yet had been
written upon it. I decided to undertake an investigation of it.

It was necessary to find a place in which to conduct the experiments. My
husband obtained from the director of the School the authorization to
use a glassed-in study on the ground floor which was then being used as
a storeroom and machine shop.


[Illustration: _Henri Manuel, Paris._

Pierre and Marie Curie in their laboratory, where radium was
discovered.]


In order to go beyond the results reached by Becquerel, it was necessary
to employ a precise quantitative method. The phenomenon that best lent
itself to measurement was the conductibility produced in the air by
uranium rays. This phenomenon, which is called _ionization_, is produced
also by X-rays and investigation of it in connection with them had made
known its principal characteristics.

For measuring the very feeble currents that one can make pass through
air ionized by uranium rays, I had at my disposition an excellent method
developed and applied by Pierre and Jacques Curie. This method consists
in counterbalancing on a sensitive electrometer the quantity of
electricity carried by the current with that which a piezo-electric
quartz can furnish. The installation therefore required a Curie
electrometer, a piezo-electric quartz, and a chamber of ionization,
which last was formed by a plate condenser whose higher plate was joined
to the electrometer, while the lower plate, charged with a known
potential, was covered with a thin layer of the substance to be
examined. Needless to say, the place for such an electrometric
installation was hardly the crowded and damp little room in which I had
to set it up.

My experiments proved that the radiation of uranium compounds can be
measured with precision under determined conditions, and that this
radiation is an atomic property of the element of uranium. Its intensity
is proportional to the quantity of uranium contained in the compound,
and depends neither on conditions of chemical combination, nor on
external circumstances, such as light or temperature.

I undertook next to discover if there were other elements possessing the
same property, and with this aim I examined all the elements then known,
either in their pure state or in compounds. I found that among these
bodies, thorium compounds are the only ones which emit rays similar to
those of uranium. The radiation of thorium has an intensity of the same
order as that of uranium, and is, as in the case of uranium, an atomic
property of the element.

It was necessary at this point to find a new term to define this new
property of matter manifested by the elements of uranium and thorium. I
proposed the word radioactivity which has since become generally
adopted; the radioactive elements have been called radio elements.

During the course of my research, I had had occasion to examine not only
simple compounds, salts and oxides, but also a great number of minerals.
Certain ones proved radioactive; these were those containing uranium and
thorium; but their radioactivity seemed abnormal, for it was much
greater than the amount I had found in uranium and thorium had led me to
expect.

This abnormality greatly surprised us. When I had assured myself that it
was not due to an error in the experiment, it became necessary to find
an explanation. I then made the hypothesis that the ores uranium and
thorium contain in small quantity a substance much more strongly
radioactive than either uranium or thorium. This substance could not be
one of the known elements, because these had already been examined; it
must, therefore, be a new chemical element.

I had a passionate desire to verify this hypothesis as rapidly as
possible. And Pierre Curie, keenly interested in the question, abandoned
his work on crystals (provisionally, he thought) to join me in the
search for this unknown substance.

We chose, for our work, the ore pitchblende, a uranium ore, which in its
pure state is about four times more active than oxide of uranium.

Since the composition of this ore was known through very careful
chemical analysis, we could expect to find, at a maximum, 1 per cent of
new substance. The result of our experiment proved that there were in
reality new radioactive elements in pitchblende, but that their
proportion did not reach even a millionth per cent!

The method we employed is a _new method in chemical research based on
radioactivity_. It consists in inducing separation by the ordinary means
of chemical analysis, and of measuring, under suitable conditions, the
radioactivity of all the separate products. By this means one can note
the chemical character of the radioactive element sought for, for it
will become concentrated in those products which will become more and
more radioactive as the separation progresses. We soon recognized that
the radioactivity was concentrated principally in two different chemical
fractions, and we became able to recognize in pitchblende the presence
of at least two new radioactive elements: polonium and radium. We
announced the existence of polonium in July, 1898, and of radium in
December of the same year.[7]

In spite of this relatively rapid progress, our work was far from
finished. In our opinion, there could be no doubt of the existence of
these new elements, but to make chemists admit their existence, it was
necessary to isolate them. Now, in our most strongly radioactive
products (several hundred times more active than uranium), the polonium
and radium were present only as traces. The polonium occurred associated
with bismuth extracted from pitchblende, and radium accompanied the
barium extracted from the same mineral. We already knew by what methods
we might hope to separate polonium from bismuth and radium from barium;
but to accomplish such a separation we had to have at our disposition
much larger quantities of the primary ore than we had.

It was during this period of our research that we were extremely
handicapped by inadequate conditions, by the lack of a proper place to
work in, by the lack of money and of personnel.

Pitchblende was an expensive mineral, and we could not afford to buy a
sufficient quantity. At that time the principal source of this mineral
was at St. Joachimsthal (Bohemia) where there was a mine which the
Austrian government worked for the extraction of uranium. We believed
that we would find all the radium and a part of the polonium in the
residues of this mine, residues which had so far not been used at all.
Thanks to the influence of the Academy of Sciences of Vienna, we secured
several tons of these residues at an advantageous price, and we used it
as our primary material. In the beginning we had to draw on our private
resources to pay the costs of our experiment; later we were given a few
subventions and some help from outside sources.

The question of quarters was particularly serious; we did not know where
we could conduct our chemical treatments. We had been obliged to start
them in an abandoned storeroom across a court from the workroom where we
had our electrometric installation. This was a wooden shed with a
bituminous floor and a glass roof which did not keep the rain out, and
without any interior arrangements. The only objects it contained were
some worn pine tables, a cast-iron stove, which worked badly, and the
blackboard which Pierre Curie loved to use. There were no hoods to carry
away the poisonous gases thrown off in our chemical treatments, so that
it was necessary to carry them on outside in the court, but when the
weather was unfavorable we went on with them inside, leaving the windows
open.


[Illustration: A view of the extraction of radium in the old
shed where the first radium was obtained.]


In this makeshift laboratory we worked practically unaided during two
years, occupying ourselves as much with chemical research as with the
study of the radiation of the increasingly active products we were
obtaining. Then it became necessary for us to divide our work. Pierre
Curie continued the investigations on the properties of radium, while I
went ahead with the chemical experiments which had as their objective
the preparation of pure radium salts. I had to work with as much as
twenty kilogrammes of material at a time, so that the hangar was filled
with great vessels full of precipitates and of liquids. It was
exhausting work to move the containers about, to transfer the liquids,
and to stir for hours at a time, with an iron bar, the boiling material
in the cast-iron basin. I extracted from the mineral the radium-bearing
barium and this, in the state of chloride, I submitted to a fractional
crystallization. The radium accumulated in the least soluble parts, and
I believed that this process must lead to the separation of the chloride
of radium. The very delicate operations of the last crystallizations
were exceedingly difficult to carry out in that laboratory, where it was
impossible to find protection from the iron and coal dust. At the end of
a year, results indicated clearly that it would be easier to separate
radium than polonium; that is why we concentrated our efforts in this
direction. We examined the radium salts we obtained with the aim of
discovering their powers and we loaned samples of the salts to several
scientists,[8] in particular to Henri Becquerel.

During the years 1899 and 1900, Pierre Curie published with me a memoir
on the discovery of the induced radioactivity produced by radium. We
published another paper on the effects of the rays: the luminous
effects, the chemical effects, etc.; and still another on the electric
charge carried by certain of the rays. And, finally, we made a general
report on the new radioactive substances and their radiations, for the
Congress of Physics which met in Paris in 1900. My husband published,
besides, a study of the action of a magnetic field on radium rays.


[Illustration: Pierre Curie with the quartz piezo-electroscope
he invented, by which rays of radium are measured.]


The main result of our investigations and of those of other scientists
during these years, was to make known the nature of the rays emitted by
radium, and to prove that they belonged to three different categories.
Radium emits a stream of active corpuscles moving with great speed.
Certain of them carry a positive charge and form the Alpha rays; others,
much smaller, carry a negative charge and form Beta rays. The movements
of these two groups are influenced by a magnet. A third group is
constituted by the rays that are insensible to the action of a magnet,
and that, we know to-day, are a radiation similar to light and to
X-rays.

We had an especial joy in observing that our products containing
concentrated radium were all spontaneously luminous. My husband who had
hoped to see them show beautiful colorations had to agree that this
other unhoped-for characteristic gave him even a greater satisfaction
than that he had aspired to.

The Congress of 1900 offered us an opportunity to make known, at closer
range, to foreign scientists, our new radioactive bodies. This was one
of the points on which the interest of this Congress chiefly centered.

We were at this time entirely absorbed in the new field that opened
before us, thanks to the discovery so little expected. And we were very
happy in spite of the difficult conditions under which we worked. We
passed our days at the laboratory, often eating a simple student's lunch
there. A great tranquillity reigned in our poor, shabby hangar;
occasionally, while observing an operation, we would walk up and down
talking of our work, present and future. When we were cold, a cup of hot
tea, drunk beside the stove, cheered us. We lived in a preoccupation as
complete as that of a dream.

Sometimes we returned in the evening after dinner for another survey of
our domain. Our precious products, for which we had no shelter, were
arranged on tables and boards; from all sides we could see their
slightly luminous silhouettes, and these gleamings, which seemed
suspended in the darkness, stirred us with ever new emotion and
enchantment.

Actually, the employees of the School owed Pierre Curie no service. But
nevertheless the laboratory helper whom he had had to aid him when he
was laboratory chief had always continued to help him as much as he
could in the time at his disposal. This good man, whose name was Petit,
felt a real affection and solicitude for us, and many things were made
easier because of his good will and the interest he took in our success.


[Illustration: A view of the extraction of radium in the old
shed where the first radium was obtained.]


We had begun our research in radioactivity quite alone, but because of
the magnitude of the undertaking, we were more and more convinced of the
utility of inviting collaboration. Already in 1898, one of the
laboratory chiefs of the School, G. Bemont, had given us temporary aid.
And toward 1900 Pierre Curie associated with him a young chemist, André
Debierne, preparator under Friedel, who held him in high esteem. André
Debierne gladly accepted Pierre Curie's proposal that he occupy himself
with the investigation of radioactivity; and he undertook, in
particular, the search for a new radio element, which we suspected
existed in the iron group and in rare earths. He discovered the element
actinium. Even though he carried on his work in the laboratory of
physical chemistry at the Sorbonne, directed by Jean Perrin, he
frequently came to visit us in our storeroom, and was soon an intimate
friend of ours, and of Doctor Curie and the children.

About this same time, George Sagnac, a young physicist engaged in the
study of X-rays, often came to discuss with my husband the analogies one
could expect to find between these rays, and their secondary rays, and
the radiations of radioactive bodies. They worked together on the
investigation of the electric charge carried by the secondary rays.

Besides our collaborators we saw very few persons in the laboratory;
however, from time to time some physicist or chemist came to see our
experiments, or to ask Pierre Curie for advice or information; for his
authority in several branches of physics was very well recognized. And
then there were discussions before the blackboard,--discussions which
are pleasantly remembered to-day, because they stimulated an interest in
science and an ardor for work without interrupting any course of
reflection, and without troubling that atmosphere of peace and
contemplation which is the true atmosphere of the laboratory.


[Footnote 7: This last publication was issued in common with G.
Bemont, who had collaborated with us in our experiments.]

[Footnote 8: I quote, as an example, a letter addressed to Pierre Curie
by A. Paulsen, thanking him for radioactive products loaned him in 1899:

                  "Den Damke Nordl's Expedition
                      Akureyi, 16 Oct. 1899.

Monsieur, and most honored colleague,

"I thank you warmly for your letter of August 1, which I have just
received in the north of Iceland.

"We have abandoned all the methods hitherto employed to establish in a
fixed conductor the potential that exists at certain points in the mass
of air that surrounds it, and are using only your radiant powder.

"Accept, Monsieur, and most honored colleague, my respectful salutations
and my renewed thanks for the great services you have rendered my
expedition.

                            "ADAM PAULSEN."]




CHAPTER VI

THE STRUGGLE FOR MEANS TO WORK. THE
BURDEN OF CELEBRITY. THE FIRST ASSISTANCE
FROM THE STATE. IT COMES TOO LATE


In spite of our desire to concentrate our entire effort on the work in
which we were engaged, and in spite of the fact that our needs were so
modest, we were forced to recognize, toward 1900, that some increase in
our income was indispensable. Pierre Curie had few illusions about his
chances of obtaining an important chair in the University of Paris,
which would, even though it meant no large salary, have sufficed for the
small needs of our family, and enabled us to live without a
supplementary revenue. Since he was neither a graduate of the Normal
School nor of the Polytechnic, he lacked the support, often decisive,
which these big schools give their pupils; and the posts to which he
might justly have aspired, because of his achievements, were given to
others, without anyone's even thinking of him as a possible candidate.
At the beginning of 1898, he asked, without success, for the Chair of
Physical Chemistry left vacant by the death of Salet, and this failure
convinced him that he had no chance of advancement. He was appointed,
however, in March, 1900, to the position of assistant professor
(_répétiteur_) in the Polytechnic School, but he kept his post only
six months.

In the spring of 1900, there came an unexpected offer, that of the Chair
of Physics in the University of Geneva. The doyen of that University
made the invitation in the most cordial manner, and insisted that the
University was ready to make an exceptional effort to secure a scientist
of such high repute. The advantages of this position were that the
salary was larger than the average one, that it carried the promise of
the development of a Physics Laboratory adequate to our needs, and that
an official position for me would be provided in this laboratory. Such a
proposition merited a most careful consideration, so we made a visit to
the University of Geneva, where our reception was the most encouraging
possible.

This was a grave decision for us to make. Geneva presented material
advantages, and the opportunity of a life comparable in its tranquillity
with that in the country. Pierre Curie was, therefore, tempted to
accept, and it was only our immediate interest in our researches in
radium that made him finally decide not to. He feared the interruption
of our investigations which such a change must involve.

At this moment the Chair of Physics in the physics, chemistry and
natural history course at the Sorbonne, obligatory for students of
medicine, and familiarly known as P.C.N., was vacant; he applied, and
was appointed, due to the influence of Henri Poincaré, who was anxious
to free him from the necessity of quitting France. At the same time I
was given charge of the physics lectures in the Normal School for Girls
at Sèvres.

So we remained in Paris, and with our income increased. But we were at
the same time working under increasingly difficult conditions. Pierre
Curie was doing double teaching; and that in the P.C.N., with its very
large number of students, fatigued him greatly. As for myself, I had to
give much time to the preparation of my lectures at Sèvres, and to the
organization of the laboratory work there, which I found very
insufficient.

Moreover, Pierre Curie's new position did not bring with it a
laboratory; a little office and a single work room were all that he had
at his disposition in the annex (12 rue Cuvier) of the Sorbonne, which
served as teaching quarters for the P.C.N. And yet he felt it absolutely
necessary to go ahead with his own work. In fact, the rapid extension of
his investigations in radioactivity had made him determine that in his
new position at the Sorbonne he would receive students and start them in
research. He therefore took steps to find larger available working
quarters. Those who have taken similar steps realize the wall of
financial and administrative obstacles against which he was throwing
himself, and realize the large number of official letters, visits, and
of requests the least success entailed. All this thoroughly wearied and
discouraged Pierre Curie. He was obliged, too, constantly, to keep
traveling back and forth between the laboratories of the P.C.N. and the
hangar of the School of Physics where we still continued our work.

And besides these difficulties, we found that we could not make further
progress without the aid of industrial means of treating our raw
material. Fortunately certain expedients and generous assistance solved
this question.

As early as 1899 Pierre Curie succeeded in organizing a first industrial
experiment, using for it a chance installation placed at his disposition
by the Central Society of Chemical Products, with which he had had
relations in connection with the construction of his balances. The
technical details had been arranged very successfully by André
Debierne, and the operations brought good results, even though it had
been necessary to train a special personnel for this chemical work which
demanded special precautions.

Our investigations had started a general scientific movement, and
similar work was being undertaken in other countries. Toward these
efforts Pierre Curie maintained a most disinterested and liberal
attitude. With my agreement he refused to draw any material profit from
our discovery. We took no copyright, and published without reserve all
the results of our research, as well as the exact processes of the
preparation of radium. In addition, we gave to those interested whatever
information they asked of us. This was of great benefit to the radium
industry, which could thus develop in full freedom, first in France,
then in foreign countries, and furnish to scientists and to physicians
the products which they needed. This industry still employs to-day, with
scarcely any modifications, the processes indicated by us.[9]

Even though our industrial experiment yielded good results, again our
slender resources made it difficult to make further progress. Inspired
by our attempt, a French industrial, Armet de Lisle, had the idea, which
seemed daring at that epoch, of founding a veritable radium factory that
would furnish this product to physicians, whose interest in the
biological effects of radium and its possible therapeutic applications
had been aroused by the publication of various investigations. The
project proved a success because he could employ men already trained by
us in the delicate processes of this manufacture. Radium was then
regularly placed on sale, at a high price, it is true, because of the
special conditions under which it had to be made, and because, too, of
the immediate rise in the cost of the minerals necessary to its
production.[10]

I should like to express, here, our appreciation of the spirit in which
Armet de Lisle offered to cooperate with us. In an entirely
disinterested manner he placed at our disposition a little working place
in his factory and a part of the means necessary for us to use it. Other
funds were added either by ourselves, or came through subventions, of
which the most important, accorded in 1902 by the Academy of Sciences,
amounted to 20,000 francs.

It was in this way that we were able to utilize the ore we had acquired
little by little in the preparation of a certain quantity of radium,
which we used constantly in our research. The radium-bearing barium was
extracted in the factory, and I carried on its purification and
fractional crystallization in the laboratory. In 1902 I succeeded in
preparing a decigramme of chloride of pure radium which gave only the
spectrum of the new element, radium. I made a first determination of the
atomic weight of this new element, an atomic weight much higher than
that of barium. Thus the chemical individuality of radium was completely
established, and the reality of radioelements was a known fact about
which there could be no further controversy.

I based my doctor's thesis, presented in 1903, on these investigations.

Later, the quantity of radium extracted for the laboratory was
increased, and in 1907 I was able to make a second and more precise
determination of the atomic weight as 225.35--one accepts now the number
226. I succeeded, too, jointly with André Debierne, in obtaining radium
in the state of metal. The total quantity of radium I prepared and gave
to the laboratory, in agreement with Pierre Curie's desire, amounted to
more than a gramme of radium element.

The activity of pure radium exceeded all our expectations. For equal
weights this substance emits a radiation more than a million times more
intense than uranium. To offset this, the quantity of radium contained
in uranium minerals is scarcely more than three decigrammes of radium to
the ton of uranium. There is a very close relation between these two
substances. In fact, we know to-day that radium is produced in the
minerals at the expense of uranium.

The years that followed his nomination to the P.C.N. were hard for
Pierre Curie. He had to face the many anxieties incident to the
organization of a complicated system of work when his happiness depended
on his being able to concentrate his efforts on a single determined
subject. The physical fatigue due to the numerous courses he was obliged
to give was so great that he suffered from attacks of acute pain, which
in his overtaxed condition became more and more frequent.

It was therefore vitally important, if he was to spare his energy and
keep his health, that the burden of his professional duties be
lightened. He decided to apply for the Chair of Mineralogy, which was
vacant, at the Sorbonne, for which he was entirely qualified because of
his profound knowledge and his important publications on the theories of
the physics of crystals. Yet his candidacy failed.

During this painful period he nevertheless managed, by a truly
superhuman effort, successfully to complete and publish several
investigations that he had made either alone or in collaboration:


Investigations on induced radioactivity (in collaboration
  with A. Debierne).

Investigations on the same subject (in collaboration
  with J. Danne).

Investigations on the conductibility provoked in
  dielectric liquids by the rays of radium and the
  Roentgen rays.

Investigations on the law of the decrease of the
  emanation of radium and on the radioactive
  constants that characterize this emanation and
  its active deposit.

Discovery of the liberation of heat produced by
  radium (in collaboration with A. Laborde).

Investigations on the diffusion of the emanation of
  radium in the air (in collaboration with J.
  Danne).

Investigation on the radioactivity of gases from
  thermal springs (in collaboration with A.
  Laborde).

Investigation on the physiological effects of
  radium rays (in common with Henri Becquerel).

Investigation on the physiological action of the
  radium emanation (in common with Bouchard
  and Balthazard).

Notes on the apparatus for the determination of
  magnetic constants (in common with C. Cheneveau).


All these investigations in radioactivity are fundamental and touch very
varied subjects. Several have as their aim the study of the emanation,
that strange gaseous body that radium produces and which is largely
responsible for the intense radiation commonly attributed to the radium
itself. Pierre Curie demonstrated by a searching examination the
rigorous and invariable law according to which the emanation destroys
itself, no matter what the conditions are in which it finds itself.
To-day the emanation of radium, harvested in tiny phials, is commonly
employed by physicians as a therapeutic agent. Technical considerations
make its employment preferable to the direct use of radium, and in this
case no physician can proceed without consulting the numerical chart
which tells how much of this emanation has disappeared each day, despite
the fact that it is cloistered in its little glass prison. It is this
same emanation that is found in small quantities in mineral waters, and
that plays a part in their curative effects.

More striking still was the discovery of the discharge of heat from
radium. Without any alteration in appearance this substance releases
each hour a quantity of heat sufficient to melt its own weight of ice.
When well protected against this external loss, radium heats itself. Its
temperature can rise 10 degrees or more above that of the surrounding
atmosphere. This defied all contemporary scientific experience.

Finally, I cannot pass in silence, because of their various
repercussions, the experiments connected with the physiological effects
of radium.

In order to test the results that had just been announced by F. Giesel,
Pierre Curie voluntarily exposed his arm to the action of radium during
several hours. This resulted in a lesion resembling a burn, that
developed progressively and required several months to heal. Henri
Becquerel had by accident a similar burn as a result of carrying in his
vest pocket a glass tube containing radium salt. He came to tell us of
this evil effect of radium, exclaiming in a manner at once delighted and
annoyed: "I love it, but I owe it a grudge!"

Since he realized the interest in these physiological effects of radium,
Pierre Curie undertook, in collaboration with physicians, the
investigations to which I have just referred, submitting animals to the
action of radium emanation. These studies formed the point of departure
in radium therapy. The first attempts at treatment with radium were made
with products loaned by Pierre Curie, and had as their object the cure
of lupus and other skin lesions. Thus radium therapy, an important
branch of medicine, and frequently designated as _Curietherapie_, was
born in France, and was developed first through the investigations of
French physicians (Danlos, Oudin, Wickham, Dominici, Cheron, Degrais,
and others).[11]

In the meantime the great impetus given to the study of radioactivity
abroad led to a rapid succession of new discoveries. Many scientists
engaged in the search for other radio elements, using the new method of
chemical analysis, with the aid of radiation, that we had inaugurated.
Thus were found the mesothorium now used by physicians and manufactured
industrially, radio-thorium, ionium, protoactinium, radio-lead, and
other substances. At present we know, in all, about thirty radio
elements (among which three are gases, or emanations), but among them
all radium still plays the most important part, because of the great
intensity of its radiation, which diminishes only extremely slowly
during the course of years.

The year 1903 was especially important in the development of the new
science. In this year the investigation of radium, the new chemical
element, was achieved, and Pierre Curie demonstrated the astonishing
discharge of heat by this element, which nevertheless remained unaltered
in appearance. In England, Ramsay and Soddy announced a great discovery.
They proved that radium continually produces helium gas and under
conditions that force one to believe in an atomic transformation. If,
indeed, radium salt heated to its melting point is confined for some
time in a sealed glass tube, entirely emptied of air, one can, in
reheating it, make it throw off a small quantity of helium, easy to
measure and to recognize from the character of its spectrum. This
fundamental experiment has received numerous confirmations. It furnished
us the first example of a transformation of atoms, independent, it is
true, of our will, but at the same time it reduces to nothing the theory
of the absolute fixity of the atomic edifice.

All these facts, along with others formerly known, were made the object
of a synthesis of the highest value, in a work by E. Rutherford and F.
Soddy, who proposed a theory of radioactive transformations, to-day
universally adopted. According to this theory, each radio element, even
when it appears unchanged, is undergoing a spontaneous transformation,
and the more rapid the transformation, the more intense is the
radiation.[12]

A radioactive atom can transform itself in two ways: it can expel from
itself an atom of helium, which, thrown off at an enormous speed and
with a positive charge, constitutes an Alpha ray. Or, instead, it can
detach from its structure a much smaller fragment, one of those
electrons to which we have become accustomed in modern physics, and
whose mass, 1800 times smaller than that of an atom of hydrogen when its
speed is moderate, grows excessively when its speed approaches that of
light. These electrons, which carry a negative charge, form the Beta
rays. Whatever the detached fragment, the residual atom no longer
resembles the primitive atom. Thus when the atom of radium has expelled
an atom of helium, the residue is an atom of gaseous emanation. This
residue changes in its turn, and the process is not arrested until the
attainment of a last residue which is stable and does not give off any
radiation. This stable matter is inactive matter.

Thus the Alpha and Beta rays result from the fragmentation of atoms.
Gamma-rays are a radiation analogous to light, which accompanies the
cataclysm of the atomic transformation. They are very penetrating, and
are the ones most used in the therapeutic methods so far developed.[13]

We can see in all this that radio elements form families, in which each
member derives from a preceding member by direct descent the primary
elements being uranium and thorium. We can in particular prove that
radium is a descendant of uranium, and that polonium is a descendant of
radium. Since each radio element, at the same time that it is formed by
the mother substance, destroys itself, it cannot accumulate in the
presence of this mother substance beyond a determined proportion, which
explains why the relation between radium and uranium remains constant in
the very ancient unaltered minerals.

The spontaneous destruction of radio elements takes place according to a
fundamental law, called the _exponential law_, according to which the
quantity of each radio element diminishes by one-half in a time always
the same, called a period, this time-period making it possible to
determine without ambiguity the element under consideration. These
periods, which can be measured by diverse methods, vary greatly. The
period of uranium is several billions of years; that of radium is about
1600 years; that of its emanation a little less than four days; and
there are among the following descendants some whose period is the small
fraction of a second. The exponential law has a profound philosophic
bearing; it indicates that the transformation is produced according to
the laws of probability. The causes that determine the transformation
are a mystery to us, and we do not yet know if they derive from causal
conditions outside the atom, or from conditions of internal instability.
In many cases, up to the present, no exterior action has shown itself
effective in influencing the transformation.

This rapid succession of discoveries which overthrew familiar scientific
conceptions long held in physics and chemistry did not fail to meet, at
first, with doubts and incredulity. But the great part of the scientific
world received them with enthusiasm. At the same time Pierre Curie's
fame grew in France and in foreign countries. Already in 1901 the
Academy of Sciences had awarded him the Lacaze prize. In 1902, Mascart,
who had many times given him most valuable aid, decided to propose him
as a member of the Academy of Sciences. It was not easy for Pierre Curie
to agree to this, believing, as he did, that the Academy should elect
its members without the necessity of any preliminary solicitation or
paying of calls. Nevertheless, because of the friendly insistence of
Mascart, and above all because the Physics Section of the Academy had
already declared itself unanimously in his favor, he presented himself.
In spite of this, however, he failed of election, and it was only in
1905 that he became a member of the Institute, a membership which did
not last even a year. He was also elected to several academies and
scientific societies in other countries, and given an honorary doctor's
degree by several universities.

During 1903 we went to London at the invitation of the Royal
Institution, before which my husband was to lecture on radium. On this
occasion he had a most enthusiastic reception. He was especially happy
to see here again Lord Kelvin, who had always expressed an affection for
him, and who, despite his advanced age, preserved an interest,
perennially young, in science. The illustrious scientist showed, with
touching satisfaction, a glass vial containing a grain of radium salt
that Pierre Curie had given him. We met here also other celebrated
scientists, as Crookes, Ramsay, and J. Dewar. In collaboration with the
latter, Pierre Curie published investigations on the discharge of heat
by radium at very low temperatures, and upon the formation of helium in
radium salt.

A few months later the Davy medal was conferred upon him (and also upon
me) by the Royal Society of London, and at almost the same time, we
received, together with Henri Becquerel, the Nobel prize for physics.
Our health prevented us from attending the ceremony for the awarding of
this prize in December, and it was only in June, 1905, that we were able
to go to Stockholm where Pierre Curie gave his Nobel lecture. We were
most cordially received and had the felicity of seeing the admirable
Swedish nature in its most brilliant aspect.

The award of the Nobel prize was an important event for us because of
the prestige carried by the Nobel foundation, only recently founded
(1901). Also, from a financial point of view, the half of the prize
represented an important sum. It meant that in the future Pierre Curie
could turn over his teaching in the School of Physics to Paul Langevin,
one of his former students, and a physicist of great competence. He
could also engage a preparator to aid him in his work.

But at the same time the publicity this very happy event entailed bore
very heavily on a man who was neither prepared for it, nor accustomed to
it. There followed an avalanche of visits, of letters, of demands for
articles and lectures, which meant a constant enervation, fatigue, and
loss of time. He was kind and did not like to refuse a request; but on
the other hand, he had to recognize that he could not accede to the
solicitations that overwhelmed him without disastrous results to his
health, as well as to his peace of mind, and his work. In a letter to
Ch. Ed. Guillaume, he said:


"People ask me for articles and lectures, and after a few years are
passed, the very persons who make these demands will be astonished to
see that we have not accomplished any work."


And in other letters of the same period, written to E. Gouy, he
expressed himself as follows:


                  "20 March 1902

"As you have seen, fortune favors us at this moment; but these favors of
fortune do not come without many worries. We have never been less
tranquil than at this moment. There are days when we scarcely have time
to breathe. And to think that we dreamed of living in the wild, quite
removed from human beings!"


                  "22 January 1904

"MY DEAR FRIEND:

"I have wanted to write to you for a long time; excuse me if I have not
done so. The cause is the stupid life which I lead at present. You have
seen this sudden infatuation for radium, which has resulted for us in
all the advantages of a moment of popularity. We have been pursued by
journalists and photographers from all countries of the world; they have
gone even so far as to report the conversation between my daughter and
her nurse, and to describe the black-and-white cat that lives with
us.... Further, we have had a great many appeals for money.... Finally,
the collectors of autographs, snobs, society people, and even at times,
scientists, have come to see us--in our magnificent and tranquil
quarters in the laboratory--and every evening there has been a
voluminous correspondence to send off. With such a state of things I
feel myself invaded by a kind of stupor. And yet all this turmoil will
not perhaps have been in vain, if it results in my getting a chair and
a laboratory. To tell the truth, it will be necessary to create the
chair, and I shall not have the laboratory at first. I should have
preferred the reverse, but Liard wishes to take advantage of the present
moment to bring about the creation of a new chair that will later be
acquired for the university. They are to establish a chair without a
fixed program, which will be something like a course in the Collège de
France, and I believe I shall be obliged to change my subject each year,
which will be a great trial to me."


                  "31 January 1905

"... I have had to give up going to Sweden. We are, as you see, most
irregular in our relations with the Swedish Academy; but, to tell the
truth, I can only keep up by avoiding all physical fatigue. And my wife
is in the same condition; we can no longer dream of the great work days
of times gone by.

"As to research, I am doing nothing at present. With my course, my
students, apparatus to install, and the interminable procession of
people who come to disturb me without serious reason, the days pass
without my having been able to achieve anything useful at this end."


                  "25 July 1905

"MY DEAR FRIEND:

"We have regretted so much being deprived of your visit this year, but
hope to see you in October. If we do not make an effort from time to
time, we end by losing touch with our best and most congenial friends,
and in keeping company with others for the simple reason that it is easy
to meet them.

"We continue to lead the same life of people who are extremely occupied,
without being able to accomplish anything interesting. It is now more
than a year since I have been able to engage in any research, and I have
no moment to myself. Clearly I have not yet discovered a means to defend
ourselves against this frittering away of our time which is nevertheless
extremely necessary. Intellectually, it is a question of life or death."


                  "7 November 1905

"I begin my course tomorrow but under very bad conditions for the
preparation of my experiments. The lecture room is at the Sorbonne, and
my laboratory is in the rue Cuvier. Besides, a great number of other
courses are given in the same lecture room, and I can use it only one
morning for the preparation of my own.

"I am neither very well, nor very ill; but I am easily fatigued, and I
have left but very little capacity for work. My wife, on the contrary,
leads a very active life, between her children, the School at Sèvres,
and the laboratory. She does not lose a minute, and occupies herself
more regularly than I can with the direction of the laboratory in which
she passes the greater part of the day."


To sum up: despite these outside complications, our life, by a common
effort of will, remained as simple and as retired as formerly. Toward
the close of 1904 our family was increased by the birth of a second
daughter. Eve Denise was born in the modest house in Boulevard
Kellermann, where we still lived with Doctor Curie, seeing only a few
friends.

As our elder daughter grew up, she began to be a little companion to her
father, who took a lively interest in her education and gladly went for
walks with her in his free times, especially on his vacation days. He
carried on serious conversations with her, replying to all her questions
and delighting in the progressive development of her young mind. From
their early age, his children enjoyed his tender affection, and he never
wearied of trying to understand these little beings, in order to be able
to give them the best he had to give.

With his great success in other countries, the complete appreciation of
Pierre Curie in France, however tardily, did at last follow. At
forty-five he found himself in the first rank of French scientists and
yet, as a teacher, he occupied an inferior position. This abnormal state
of affairs aroused public opinion in his favor, and under the influence
of this wave of feeling, the director of the Academy of Paris, L. Liard,
asked Parliament to create a new professorship in the Sorbonne, and at
the beginning of the academic year 1904-05 Pierre Curie was named
titular professor of the Faculty of Sciences of Paris. A year later he
definitely quitted the School of Physics where his substitute, Paul
Langevin, succeeded him.

This new professorship was not established without a few difficulties.
The first project had provided for a new chair, but not for a
laboratory. And Pierre Curie felt that he could not accept a situation
which involved the risk of losing even the mediocre means of work that
he then had, instead of offering better ones. He wrote, therefore, to
his chiefs, that he had decided to remain at the P.C.N. His firmness won
the day. To the new chair was added a fund for a laboratory and
personnel for the new work (a chief of laboratory, a preparator, and a
laboratory boy). The position of chief of laboratory was offered to me,
which was a cause of very great satisfaction to my husband.

It was not without regret that we left the School of Physics, where we
had known such happy work days, despite their attendant difficulties. We
had become particularly attached to our hangar, which continued to
stand, though in a state of increasing decay, for several years, and we
went to visit it from time to time. Later it had to be pulled down to
make way for a new building for the Physics School, but we have
preserved photographs of it. Warned of its approaching destruction by
the faithful Petit, I made my last pilgrimage there, alas, alone. On the
blackboard there was still the writing of him who had been the soul of
the place; the humble refuge for his research was all impregnated with
his memory. The cruel reality seemed some bad dream; I almost expected
to see the tall figure appear, and to hear the sound of the familiar
voice.

Even though Parliament had voted the creation of a new chair, it did not
go so far as to consider the simultaneous founding of a laboratory which
was, nevertheless, necessary to the development of the new science of
radioactivity. Pierre Curie therefore kept the little workroom at the
P.C.N., and secured as a temporary solution of his difficulty the use of
a large room, then not being used by the P.C.N. He arranged, too, to
have a little building consisting of two rooms and a study set up in the
court.

One cannot help feeling sorrow in realizing that this was a last
concession, and that actually one of the first French scientists never
had an adequate laboratory to work in, and this even though his genius
had revealed itself as early as his twentieth year. Without doubt if he
had lived longer, he would have had the benefit of satisfactory
conditions for his work, but he was still deprived of them at his death
at the premature age of forty-eight. Can we fully imagine the regret of
an enthusiastic and disinterested worker in a great work, who is
retarded in the realization of his dream by the constant lack of means?
And can we think without a feeling of profound grief of the waste--the
one irreparable one--of the nation's greatest asset: the genius, the
powers, and the courage of its best children?

Pierre Curie had always in mind his urgent need for a good laboratory.
When, because of his great reputation, his chiefs felt obliged to try to
induce him, in 1903, to accept the decoration of the Légion d'Honneur,
he declined that distinction, remaining true to the opinion already
referred to in a preceding chapter. And the letter he wrote on this
occasion was inspired by the same feeling as that in the one previously
quoted, when he wrote to his director to refuse the _palmes
académiques_. I quote an extract:


"I pray you to thank the Minister, and to inform him that I do not in
the least feel the need of a decoration, but that I do feel the greatest
need for a laboratory."


After he was named professor at the Sorbonne, Pierre Curie had to
prepare a new course. The position had been given a very personal
character and a very general scope. He was left great freedom in the
choice of the matter he would present. Taking advantage of this freedom
he returned to a subject that was dear to him, and devoted part of his
lectures to the laws of symmetry, the study of fields of vectors and
tensors, and to the application of these ideas to the physics of
crystals. He intended to carry these lessons further, and to work out a
course that would completely cover the physics of crystallized matter
which would have been especially useful because this subject was so
little known in France. His other lessons dealt with radioactivity, set
forth the discoveries made in this new domain, and the revolution they
had caused in science.

Even though he was very much absorbed in the preparation of his course,
and often ill, my husband continued, nevertheless, to work in the
laboratory, which was becoming better and better organized. He had a
little more space now, and could receive a few students. In
collaboration with A. Laborde, he carried on investigations in mineral
waters and gases discharged from springs. This was the last work he
published.

His intellectual faculties were at this time at their height. One could
but admire the surety and rigor of his reasoning on the theories of
physics, his clear comprehension of fundamental principles, and a
certain profound sense of phenomena which he had by instinct, but which
he perfected during the course of a life entirely consecrated to
research and reflection. His skill in experiment, remarkable from the
beginning, was increased by practice. He experienced the pleasure of an
artist when he succeeded with a delicate installation. He enjoyed, too,
devising and constructing new apparatus, and I used jokingly to tell him
that he would not be happy unless he made at least an attempt of this
kind once every six months. His natural curiosity and vivid imagination
pushed him to undertakings in very varied directions; he could change
the object of his research with surprising ease.

He was scrupulously careful of scientific probity and of complete
accuracy in his publications. These are very perfect in form, and none
the less so in those parts where he applies the critical spirit to
himself, expressing his determination never to affirm anything that does
not seem entirely clear. He expresses his thought on this point in the
following words:


"In the study of unknown phenomena, one can make very general hypotheses
and then advance step by step with the help of experience. This method
of progress is sure but necessarily slow. One can, on the contrary, make
daring hypotheses in which he specifies the mechanism of phenomena. Such
a method of procedure has the advantage of suggesting certain
experiments, and, above all, of facilitating reasoning by rendering it
less abstract through the employment of an image. But on the other hand,
one cannot hope thus to conceive a complex theory in accord with
experiment. The precise hypothesis almost certainly includes a portion
of error along with a portion of truth. And this last portion, if it
exists, forms only a part of a more general proposition to which it will
be necessary in the end to return."


Moreover, even though he never hesitated to make hypotheses, he never
permitted their premature publication. He could never accustom himself
to a system of work which involved hasty publications, and was always
happier in a domain in which but a few investigators were quietly
working. The considerable vogue of radioactivity made him wish to
abandon this field of research for a time, and to return to his
interrupted studies of the physics of crystals. He dreamed also of
making an examination of diverse theoretical questions.

He gave much thought to his teaching, which constantly improved, and
which suggested to him ideas on the general orientation of studies and
on methods of teaching, which he believed should be based on contact
with experience and nature. He hoped to see his views adopted by the
Association of Professors as soon as it was formed, and to obtain the
declaration "that the teaching of the sciences must be the dominant
teaching of both the boys' and girls' lycées."

"But," he said, "such a notion would have little chance of success."

But this last period of his life, so fecund, was, alas, soon to end. His
admirable scientific career was to be suddenly broken at the very moment
when he could hope that the years of work to come would be less hard
than those which had preceded.

In 1906, quite ill and tired, he went with me and the children to spend
Easter in the Chevreuse Valley. Those were two sweet days under a mild
sun, and Pierre Curie felt the weight of weariness lighten in a healing
repose near to those who were dear to him. He amused himself in the
meadows with his little girls, and talked with me of their present and
their future.

He returned to Paris for a reunion and dinner of the Physics Society.
There he sat beside Henri Poincaré and had a long conversation with him
on methods of teaching. As we were returning on foot to our house, he
continued to develop his ideas on the culture that he dreamed of, happy
in the consciousness that I shared his views.

The following day, the 19th of April, 1906, he attended a reunion of the
Association of Professors of the Faculties of the Sciences, where he
talked with them very cordially about the aims which the Association
might adopt. As he went out from this reunion and was crossing the rue
Dauphine, he was struck by a truck coming from the Pont Neuf, and fell
under its wheels. A concussion of the brain brought instantaneous death.

So perished the hope founded on the wonderful being who thus ceased to
he. In the study room to which he was never to return, the water
buttercups he had brought from the country were still fresh.


[Footnote 9: During my recent visit to America, where a gramme of radium
was generously offered me by American women, the Buffalo Society of
Natural Sciences presented me, as a souvenir, with a publication
reviewing the development of the radium industry in the United States.
This included photographic reproductions of letters from Pierre Curie in
which he replied in as complete a manner as possible to the questions
asked by American engineers. (1902 and 1903.)]

[Footnote 10: The price of a milligramme of the element of radium was
then fixed at about 750 francs.]

[Footnote 11: These physicians were aided by the manufacturer, Armet de
Lisle, who placed at their disposition the radium needed for their first
undertakings. He founded, besides, in 1906, a laboratory for clinical
study, provided with a supply of radium. And he subventioned the first
special publication devoted to radioactivity and its applications, as a
journal under the name _Radium_, edited by J. Danne. This is an example
of generous support of science by industry, in reality still very rare
but which one wishes might become general, in the common interest of
these two branches of human activity.]

[Footnote 12: The hypothesis according to which radioactivity is bound
up with the atomic transformation of elements was first envisaged by
Pierre Curie and by me, along with other possible hypotheses, before it
was utilized by E. Rutherford. (See _Revue Scientifique_, 1900, Mme.
Curie, etc.)]

[Footnote 13: By using the unusual energy of Alpha-rays E. Rutherford
has obtained recently the rupture of certain light atoms, like those of
nitrogen.]




CHAPTER VII

THE NATION'S SORROW. THE LABORATORIES:
"SACRED PLACES"


I shall not attempt to describe the grief of the family left by Pierre
Curie. By what I have earlier said in this narrative one can understand
what he meant to his father, his brother, and his wife. He was, too, a
devoted father, tender in his love for his children, and happy to occupy
himself with them. But our daughters were still too young at this time
to realize the calamity that had befallen us. Their grandfather and I,
united in our common suffering, did what we could to see that their
childhood should not be too much darkened by the disaster.

The news of the catastrophe caused veritable consternation in the
scientific world of France, as well as in that of other countries. The
heads of the university and the professors expressed their emotion in
letters full of sympathy, and a great number of foreign scientists also
sent letters and telegrams. No less deep was the impression produced on
the public with whom Pierre Curie, despite his reserve, enjoyed great
renown. This feeling was expressed in numerous private letters coming
not only from those whom we knew, but also from persons entirely unknown
to us. At the same time the press printed articles of regret, bearing
the stamp of deep sincerity. The French government sent its condolences,
and a few rulers of foreign countries sent their personal expressions of
sympathy. One of the purest glories of France had been extinguished, and
each understood that this was a nation's sorrow.[14]

Faithful to the memory of him who had left us, we wished a simple
interment in the family vault in the little cemetery at Sceaux. There
was neither official ceremony nor address, and only his friends
accompanied him to his last home. As he thought of him who was no more,
his brother Jacques said to me: "He had all the gifts; there were not
two like him."

In order to assure the continuance of his work, the Faculty of Sciences
of Paris paid me the very great honor of asking me to take the place
that he had occupied. I accepted this heavy heritage, in the hope that I
might build up some day, in his memory, a laboratory worthy of him,
which he had never had, but where others would be able to work to
develop his idea. This hope is now partly realized, thanks to the common
initiative of the University and the Pasteur Institute, which have aimed
at the creation of a Radium Institute, composed of two laboratories, the
Curie and the Pasteur, destined for the physicochemical and the
biological study of radium rays. In touching homage to him who had
disappeared the new street leading to the Institute was named rue Pierre
Curie.

This Institute is, however, insufficient in view of the considerable
development of radioactivity and of its therapeutic applications. The
best authorized persons now recognize that France must possess a Radium
Institute comparable to those of England and America for the
_Curietherapie_ which has become an efficacious means in the battle
against cancer. It is to be hoped that with generous and far-seeing aid,
we shall have, in a few years, a Radium Institute complete and enlarged,
worthy of our country.

To honor the memory of Pierre Curie, the French Society of Physics
decided to issue a complete publication of his works. This publication,
arranged by P. Langevin and C. Cheneveau, comprises but a single volume
of about 600 pages, which appeared in 1908, and for which I wrote a
preface. This unique volume, which includes a work as important as it is
varied, is a faithful reflection of the mentality of the author. One
finds in it a great richness of ideas and of experimental facts leading
to clear and well-established results, but the exposition is limited to
the strictly necessary, and is irreproachable, one might even say
classical, in form. It is to be regretted that Pierre Curie did not use
his gifts as scientist and author in writing extended memoirs or books.
It was not the desire that was lacking; he had several cherished
projects of this nature. But he could never put them into execution
because of the difficulties with which he had to struggle during all his
working life.


And now, let us glance at this narrative as a whole, in which I have
attempted to evoke the image of a man who, inflexibly devoted to the
service of his ideal, honored humanity by an existence lived in silence,
in the simple grandeur of his genius and his character. He had the faith
of those who open new ways. He knew that he had a high mission to fulfil
and the mystic dream of his youth pushed him invincibly beyond the usual
path of life into a way which he called anti-natural because it
signified the renunciation of the pleasures of life. Nevertheless, he
resolutely subordinated his thoughts and desires to this dream, adapting
himself to it and identifying himself with it more and more completely.
Believing only in the pacific might of science and of reason, he lived
for the search of truth. Without prejudice or _parti pris_, he carried
the same loyalty into his study of things that he used in his
understanding of other men and of himself. Detached from every common
passion, seeking neither supremacy nor honors, he had no enemies, even
though the effort he had achieved in the control of himself had made of
him one of those elect whom we find in advance of their time in all the
epochs of civilization. Like them he was able to exercise a profound
influence merely by the radiation of his inner strength.

It is useful to learn how much sacrifice such a life represents. The
life of a great scientist in his laboratory is not, as many may think, a
peaceful idyll. More often it is a bitter battle with things, with one's
surroundings, and above all with oneself. A great discovery does not
leap completely achieved from the brain of the scientist, as Minerva
sprang, all panoplied, from the head of Jupiter; it is the fruit of
accumulated preliminary work. Between the days of fecund productivity
are inserted days of uncertainty when nothing seems to succeed, and when
even matter itself seems hostile; and it is then that one must hold out
against discouragement. Thus without ever forsaking his inexhaustible
patience, Pierre Curie used sometimes to say to me: "It is nevertheless
hard, this life that we have chosen."

For the admirable gift of himself, and for the magnificent service he
renders humanity, what reward does our society offer the scientist? Have
these servants of an idea the necessary means of work? Have they an
assured existence, sheltered from care? The example of Pierre Curie, and
of others, shows that they have none of these things; and that more
often, before they can secure possible working conditions, they have to
exhaust their youth and their powers in daily anxieties. Our society, in
which reigns an eager desire for riches and luxury, does not understand
the value of science. It does not realize that science is a most
precious part of its moral patrimony. Nor does it take sufficient
cognizance of the fact that science is at the base of all the progress
that lightens the burden of life and lessens its suffering. Neither
public powers nor private generosity actually accord to science and to
scientists the support and the subsidies indispensable to fully
effective work.

I invoke, in closing, the admirable pleading of Pasteur:


"If the conquests useful for humanity touch your heart, if you are
overwhelmed before the astonishing results of electric telegraphy, of
the daguerrotype, of anesthesia, and of other wonderful discoveries, if
you are jealous of the part your country may claim in the spreading of
these marvelous things, take an interest, I beg of you, in those sacred
places to which we give the expressive name of laboratories. Demand that
they be multiplied and ornamented, for these are the temples of the
future, of wealth, and of well-being. It is in them that humanity grows,
fortifies itself, and becomes better. There it may learn to read in the
works of nature the story of progress and of universal harmony, even
while its own creations are too often those of barbarism, fanaticism,
and destruction."


May this truth be widely spread, and deeply penetrate public opinion,
that the future may be less hard for the pioneers who must open up new
domains for the general good of humanity.


_Extracts from Published Appreciations_


I have chosen certain extracts from various published appreciations of
Pierre Curie in order to complete my account by a few moving testimonies
from eminent men of science.


_Henri Poincaré_:

"Curie was one of those on whom Science and France believed they had the
right to count. His age permitted far-reaching hopes; what he had
already given seemed a promise, and we knew that, living, he would not
have failed. On the night preceding his death (pardon this personal
memory) I sat next to him and he talked with me of his plans and his
ideas. I admired the fecundity and the depth of his thought, the new
aspect which physical phenomena took on when looked at through that
original and lucid mind. I felt that I better understood the grandeur of
human intelligence--and the following day, in an instant, all was
annihilated. A stupid accident brutally reminded us how little place
thought holds in the face of the thousand blind forces that hurl
themselves across the world without knowing whither they go, crushing
all in their passage.

"His friends, his colleagues understood at once the import of the loss
they suffered, but the grief extended far beyond them. In foreign
countries the most illustrious scientists joined in trying to show the
esteem in which they held our compatriot, while in our own land there
was no Frenchman, however ignorant, who did not feel more or less
vaguely what a force his nation and humanity had lost.

"Curie brought to his study of physical phenomena I do not know what
very fine sense which made him divine unsuspected analogies, and made it
possible for him to orient himself in a labyrinth of complex appearances
where others would have gone astray.... True physicists, like Curie,
neither look within themselves, nor on the surface of things, but they
know how to look through things.

"All those who knew him knew their pleasure and surety in his
acquaintance, and the delicate charm that was exhaled, one might say, by
his gentle modesty, by his naïve directness, by the fineness of his
spirit. Always ready to efface himself before his family, before his
friends, and even before his rivals, he was what one calls a 'poor
candidate'; but in our democracy candidates are the least thing we lack.

"Who would have thought that so much gentleness concealed an
intransigeant soul? He did not compromise with those general principles
on which he was nourished, nor with the particular moral ideal he had
been taught to love, that ideal of absolute sincerity, too high,
perhaps, for the world in which we live. He did not know the thousand
little accommodations with which our weakness contents itself. Moreover,
he never separated the worship of this ideal from what he rendered to
science, and he gave us a shining example of the high conception of duty
that may spring from a simple and pure love of truth. It matters little
in what God he believed; it is not the God, but faith, that performs
miracles."


_Institut de France_: Written about P. Curie by M. D. Gernez.

"All for work, all for science: this sums up the life of Pierre Curie, a
life so rich in brilliant discoveries and in the outlook of genius that
it won him practically universal admiration. In the full maturity of his
investigations whose progress he so eagerly pursued his work was ended,
to the consternation of us all, by a terrible catastrophe on the 19th of
April, 1906....

"All these honors did not dazzle him; he was and he will remain a
remarkable figure among those who make the scientific history of our
epoch. His contemporaries found in him a precious example of a devotion
to science at once unyielding and disinterested. There have been few
lives more pure and more justly famous."


_Jean Perrin_:

"Pierre Curie, whom all called a master, and whom we had the joy to
call, too, our friend, died suddenly in the fullness of his powers....
We will try to show through him, as an example, what part a powerful
genius can return to sincerity, to liberty, to the strong and calm
audacity of thought which nothing can enchain and nothing can astonish.
We acknowledge also all the greatness of the soul where these fine
qualities of intelligence and character were united in a most noble
unselfishness and most exquisite goodness.

"Those who have known Pierre Curie, know that, near him one felt awaken
the need to do and to understand. We will try to honor his memory by
spreading abroad this impression, and we will ask his pale and beautiful
face for the secret of that radiation which made all those who
approached him better men."


_C. Cheneveau_:

"... In order to realize our irreparable loss we must remember Curie's
attachment to his students.... Some of us offered him, with reason, a
veritable worship.... For myself, he was, next to my own family, one of
those I loved most. How well he knew how to surround his simple
collaborator with a great and tender affection. His immense kindness
extended even to his most humble helpers, who adored him. I have never
seen more sincere and more heart-breaking tears than those shed by the
laboratory boys on the news of his sudden death."


_Paul Langevin_:

"... The hours when one could meet him and in which one loved to talk
about his science and in which one thought with him, return each day to
recall his memory, to bring back his kindly and thoughtful face, his
luminous eyes and his beautiful, expressive head modeled by twenty-five
years passed in the laboratory, and by a life of unremittent work and
complete simplicity.

"... It is in his laboratory that my memories, still so recent, most
readily bring him back to me, as he would appear to those near to whom
he had grown older, scarcely changed by the eighteen years that have
passed since. Timid and often awkward, I began under him my laboratory
education....

"Surrounded by apparatus for the greater part conceived or modified by
himself, he manipulated it with extreme dexterity, with the familiar
gestures of the long white hands of the physicist....

"He was twenty-nine years old when I entered as a student. The mastery
which ten years, passed entirely in the laboratory, had given him,
imposed itself even on us, despite our ignorance, by the surety of his
movements and explanations, and the ease, shaded by timidity, of his
manner. We returned always with joy to the laboratory, where it was good
to work near him because we felt him working near to us in that large,
light room filled with apparatus whose forms were still a little
mysterious to us. We did not fear to enter it often to consult him, and
he sometimes admitted us, too, to perform some particularly delicate
manipulation. Probably my finest memories of my school years are those
of moments passed there standing before the blackboard where he took
pleasure in talking with us, in awakening in us fruitful ideas, and in
discussions of research which formed our taste for the things of
science. His live and contagious curiosity, the fullness and surety of
his information made him an admirable awakener of spirits."

I have wished above all, in gathering together here these few memories,
in a bouquet reverently placed upon his tomb, to help, if I can, to fix
the image of a man truly great in character and in thought, of a
wonderful representative of the genius of our race. Entirely
unfranchised from ancient servitudes, and passionately loving reason and
clarity, he was an example--as is a prophet inspired by truths of the
future--of what may be realized in moral beauty and goodness by a free
and upright spirit, of constant courage, and of a mental honesty which
made him repulse what he did not understand, and place his life in
accord with this dream.


[Footnote 14: From the great number of letters and telegrams of
condolence, I quote, as examples, these lines written by three great
scientists, today no longer living.

From M. Berthelot:

"MADAME:

"I do not wish to wait longer without sending you the sympathetic
expression of my profound grief and of that of French and foreign
scientists on the occasion of the common loss with you that we have all
experienced. We were struck as by lightning by the tragic news! So many
services already rendered science and humanity, so many services that we
awaited from that genial inventor: all this vanished in an instant, or
become already but a memory!"


From G. Lippmann:

"MADAME:

It is while traveling, and very late, that I receive the terrible news.
I feel as if I had lost a brother; I did not know by what close ties I
was attached to your husband. I know today. I suffer also for you,
Madame. Believe in my sincere and respectful devotion."


From Lord Kelvin:

"Grievously distressed by terrible news of Curie's death. When will be
funeral. We arrive Hotel Mirabeau tomorrow morning. Kelvin, Villa St.
Martin, Cannes."]




AUTOBIOGRAPHICAL NOTES
MARIE CURIE




CHAPTER I


I have been asked by my American friends to write the story of my life.
At first, the idea seemed alien to me, but I yielded to persuasion.
However, I could not conceive my biography as a complete expression of
personal feelings or a detailed description of all incidents I would
remember. Many of our feelings change with the years, and, when faded
away, may seem altogether strange; incidents lose their momentary
interest and may be remembered as if they have occurred to some other
person. But there may be in a life some general direction, some
continuous thread, due to a few dominant ideas and a few strong
feelings, that explain the life and are characteristic of a human
personality. Of my life, which has not been easy on the whole, I have
described the general course and the essential features, and I trust
that my story gives an understanding of the state of mind in which I
have lived and worked.

My family is of Polish origin, and my name is Marie Sklodowska. My
father and my mother both came from among the small Polish landed
proprietors. In my country this class is composed of a large number of
families, owners of small and medium-sized estates, frequently
interrelated. It has been, until recently, chiefly from this group that
Poland has drawn her intellectual recruits.

While my paternal grandfather had divided his time between agriculture
and directing a provincial college, my father, more strongly drawn to
study, followed the course of the University of Petrograd, and later
definitely established himself at Warsaw as Professor of Physics and
Mathematics in one of the lyceums of that city. He married a young woman
whose mode of life was congenial to his; for, although very young, she
had, what was, for that time, a very serious education, and was the
director of one of the best Warsaw schools for young girls.

My father and mother worshiped their profession in the highest degree
and have left, all over their country, a lasting remembrance with their
pupils. I cannot, even to-day, go into Polish society without meeting
persons who have tender memories of my parents.

Although my parents adopted a university career, they continued to keep
in close touch with their numerous family in the country. It was with
their relatives that I frequently spent my vacation, living in all
freedom and finding opportunities to know the field life by which I was
deeply attracted. To these conditions, so different from the usual
villegiature, I believe, I owe my love for the country and nature.

Born at Warsaw, on the 7th of November, 1867, I was the last of five
children, but my oldest sister died at the early age of fourteen, and we
were left, three sisters and a brother. Cruelly struck by the loss of
her daughter and worn away by a grave illness, my mother died at
forty-two, leaving her husband in the deepest sorrow with his children.
I was then only nine years old, and my eldest brother was hardly
thirteen.

This catastrophe was the first great sorrow of my life and threw me into
a profound depression. My mother had an exceptional personality. With
all her intellectuality she had a big heart and a very high sense of
duty. And, though possessing infinite indulgence and good nature, she
still held in the family a remarkable moral authority. She had an ardent
piety (my parents were both Catholics), but she was never intolerant;
differences in religious belief did not trouble her; she was equally
kind to any one not sharing her opinions. Her influence over me was
extraordinary, for in me the natural love of the little girl for her
mother was united with a passionate admiration.

Very much affected by the death of my mother, my father devoted himself
entirely to his work and to the care of our education. His professional
obligations were heavy and left him little leisure time. For many years
we all felt weighing on us the loss of the one who had been the soul of
the house.

We all started our studies very young. I was only six years old, and,
because I was the youngest and smallest in the class, was frequently
brought forward to recite when there were visitors. This was a great
trial to me, because of my timidity; I wanted always to run away and
hide. My father, an excellent educator, was interested in our work and
knew how to direct it, but the conditions of our education were
difficult. We began our studies in private schools and finished them in
those of the government.

Warsaw was then under Russian domination, and one of the worst aspects
of this control was the oppression exerted on the school and the child.
The private schools directed by Poles were closely watched by the police
and overburdened with the necessity of teaching the Russian language
even to children so young that they could scarcely speak their native
Polish. Nevertheless, since the teachers were nearly all of Polish
nationality, they endeavored in every possible way to mitigate the
difficulties resulting from the national persecution. These schools,
however, could not legally give diplomas, which were obtainable only in
those of the government.

The latter, entirely Russian, were directly opposed to the Polish
national spirit. All instruction was given in Russian, by Russian
professors, who, being hostile to the Polish nation, treated their
pupils as enemies. Men of moral and intellectual distinction could
scarcely agree to teach in schools where an alien attitude was forced
upon them. So what the pupils were taught was of questionable value, and
the moral atmosphere was altogether unbearable. Constantly held in
suspicion and spied upon, the children knew that a single conversation
in Polish, or an imprudent word, might seriously harm, not only
themselves, but also their families. Amidst these hostilities, they lost
all the joy of life, and precocious feelings of distrust and indignation
weighed upon their childhood. On the other side, this abnormal situation
resulted in exciting the patriotic feeling of Polish youths to the
highest degree.

Yet of this period of my early youth, darkened though it was by
mourning and the sorrow of oppression, I still keep more than one
pleasant remembrance. In our quiet but occupied life, reunions of
relatives and friends of our family brought some joy. My father was very
interested in literature and well acquainted with Polish and foreign
poetry; he even composed poetry himself and was able to translate it
from foreign languages into Polish in a very successful way. His little
poems on family events were our delight. On Saturday evenings he used to
recite or read to us the masterpieces of Polish prose and poetry. These
evenings were for us a great pleasure and a source of renewed patriotic
feelings.

Since my childhood I have had a strong taste for poetry, and I willingly
learned by heart long passages from our great poets, the favorite ones
being Mickiewecz, Krasinski and Slowacki. This taste was even more
developed when I became acquainted with foreign literatures; my early
studies included the knowledge of French, German, and Russian, and I
soon became familiar with the fine works written in these languages.
Later I felt the need of knowing English and succeeded in acquiring the
knowledge of that language and its literature.

My musical studies have been very scarce. My mother was a musician and
had a beautiful voice. She wanted us to have musical training. After her
death, having no more encouragement from her, I soon abandoned this
effort, which I often regretted afterwards.

I learned easily mathematics and physics, as far as these sciences were
taken in consideration in the school. I found in this ready help from my
father, who loved science and had to teach it himself. He enjoyed any
explanation he could give us about Nature and her ways. Unhappily, he
had no laboratory and could not perform experiments.

The periods of vacations were particularly comforting, when, escaping
the strict watch of the police in the city, we took refuge with
relatives or friends in the country. There we found the free life of the
old-fashioned family estate; races in the woods and joyous participation
in work in the far-stretching, level grain-fields. At other times we
passed the border of our Russian-ruled division (Congress Poland) and
went southwards into the mountain country of Galicia, where the Austrian
political control was less oppressive than that which we suffered. There
we could speak Polish in all freedom and sing patriotic songs without
going to prison.

My first impression of the mountains was very vivid, because I had been
brought up in the plains. So I enjoyed immensely our life in the
Carpathian villages, the view of the pikes, the excursions to the
valleys and to the high mountain lakes with picturesque names such as:
"The Eye of the Sea." However, I never lost my attachment to the open
horizon and the gentle views of a plain hill country.

Later I had the opportunity to spend a vacation with my father far more
south in Podolia, and to have the first view of the sea at Odessa, and
afterwards at the Baltic shore. This was a thrilling experience. But it
was in France that I become acquainted with the big waves of the ocean
and the ever-changing tide. All my life through, the new sights of
Nature made me rejoice like a child.

Thus passed the period of our school life. We all had much facility for
intellectual work. My brother, Doctor Sklodowski, having finished his
medical studies, became later the chief physician in one of the
principal Warsaw hospitals. My sisters and I intended to take up
teaching as our parents had done. However, my elder sister, when grown
up, changed her mind and decided to study medicine. She took the degree
of doctor at the Paris University, married Doctor Dluski, a Polish
physician, and together they established an important sanatorium in a
wonderfully beautiful Carpathian mountain place of Austrian Poland. My
second sister, married in Warsaw, Mrs. Szalay, was for many years a
teacher in the schools, where she rendered great service. Later she was
appointed in one of the lyceums of free Poland.

I was but fifteen when I finished my high-school studies, always having
held first rank in my class. The fatigue of growth and study compelled
me to take almost a year's rest in the country. I then returned to my
father in Warsaw, hoping to teach in the free schools. But family
circumstances obliged me to change my decision. My father, now aged and
tired, needed rest; his fortune was very modest. So I resolved to accept
a position as governess for several children. Thus, when scarcely
seventeen, I left my father's house to begin an independent life.

That going away remains one of the most vivid memories of my youth. My
heart was heavy as I climbed into the railway car. It was to carry me
for several hours, away from those I loved. And after the railway
journey I must drive for five hours longer. What experience was awaiting
me? So I questioned as I sat close to the car window looking out across
the wide plains.

The father of the family to which I went was an agriculturist. His
oldest daughter was about my age, and although working with me, was my
companion rather than my pupil. There were two younger children, a boy
and a girl. My relations with my pupils were friendly; after our lessons
we went together for daily walks. Loving the country, I did not feel
lonesome, and although this particular country was not especially
picturesque, I was satisfied with it in all seasons. I took the greatest
interest in the agricultural development of the estate where the methods
were considered as models for the region. I knew the progressive details
of the work, the distribution of crops in the fields; I eagerly followed
the growth of the plants, and in the stables of the farm I knew the
horses.

In winter the vast plains, covered with snow, were not lacking in charm,
and we went for long sleigh rides. Sometimes we could hardly see the
road. "Look out for the ditch!" I would call to the driver. "You are
going straight into it," and "Never fear!" he would answer, as over we
went! But these tumbles only added to the gayety of our excursions.

I remember the marvelous snow house we made one winter when the snow was
very high in the fields; we could sit in it and look out across the
rose-tinted snow plains. We also used to skate on the ice of the river
and to watch the weather anxiously, to make sure that the ice was not
going to give way, depriving us of our pleasure.

Since my duties with my pupils did not take up all my time, I organized
a small class for the children of the village who could not be educated
under the Russian government. In this the oldest daughter of the house
aided me. We taught the little children and the girls who wished to come
how to read and write, and we put in circulation Polish books which were
appreciated, too, by the parents. Even this innocent work presented
danger, as all initiative of this kind was forbidden by the government
and might bring imprisonment or deportation to Siberia.

My evenings I generally devoted to study. I had heard that a few women
had succeeded in following certain courses in Petrograd or in foreign
countries, and I was determined to prepare myself by preliminary work to
follow their example.

I had not yet decided what path I would choose. I was as much interested
in literature and sociology as in science. However, during these years
of isolated work, trying little by little to find my real preferences, I
finally turned towards mathematics and physics, and resolutely undertook
a serious preparation for future work. This work I proposed doing in
Paris, and I hoped to save enough money to be able to live and work in
that city for some time.

My solitary study was beset with difficulties. The scientific education
I had received at the lyceum was very incomplete; it was well under the
bachelorship program of a French lyceum; I tried to add to it in my own
way, with the help of books picked up at random. This method could not
be greatly productive, yet it was not without results. I acquired the
habit of independent work, and learned a few things which were to be of
use later on.

I had to modify my plans for the future when my eldest sister decided to
go to Paris to study medicine. We had promised each other mutual aid,
but our means did not permit of our leaving together. So I kept my
position for three and a half years, and, having finished my work with
my pupils, I returned to Warsaw, where a position, similar to the one I
had left, was awaiting me.

I kept this new place for only a year and then went back to my father,
who had retired some time before and was living alone. Together we
passed an excellent year, he occupying himself with some literary work,
while I increased our funds by giving private lessons. Meantime I
continued my efforts to educate myself. This was no easy task under the
Russian government of Warsaw; yet I found more opportunities than in the
country. To my great joy, I was able, for the first time in my life, to
find access to a laboratory: a small municipal physical laboratory
directed by one of my cousins. I found little time to work there, except
in the evenings and on Sundays, and was generally left to myself. I
tried out various experiments described in treatises on physics and
chemistry, and the results were sometimes unexpected. At times I would
be encouraged by a little unhoped-for success, at others I would be in
the deepest despair because of accidents and failures resulting from my
inexperience. But on the whole, though I was taught that the way of
progress is neither swift nor easy, this first trial confirmed in me the
taste for experimental research in the fields of physics and chemistry.

Other means of instruction came to me through my being one of an
enthusiastic group of young men and women of Warsaw, who united in a
common desire to study, and whose activities were at the same time
social and patriotic. It was one of those groups of Polish youths who
believed that the hope of their country lay in a great effort to develop
the intellectual and moral strength of the nation, and that such an
effort would lead to a better national situation. The nearest purpose
was to work at one's own instruction and to provide means of instruction
for workmen and peasants. In accordance with this program we agreed
among ourselves to give evening courses, each one teaching what he knew
best. There is no need to say that this was a secret organization, which
made everything extremely difficult. There were in our group very
devoted young people who, as I still believe today, could do truly
useful work.

I have a bright remembrance of the sympathetic intellectual and social
companionship which I enjoyed at that time. Truly the means of action
were poor and the results obtained could not be considerable; yet I
still believe that the ideas which inspired us then are the only way to
real social progress. You cannot hope to build a better world without
improving the individuals. To that end each of us must work for his own
improvement, and at the same time share a general responsibility for all
humanity, our particular duty being to aid those to whom we think we can
be most useful.

All the experiences of this period intensified my longing for further
study. And, in his affection for me, my father, in spite of limited
resources, helped me to hasten the execution of my early project. My
sister had just married at Paris, and it was decided that I should go
there to live with her. My father and I hoped that, once my studies were
finished, we would again live happily together. Fate was to decide
otherwise, since my marriage was to hold me in France. My father, who in
his own youth had wished to do scientific work, was consoled in our
separation by the progressive success of my work. I keep a tender memory
of his kindness and disinterestedness. He lived with the family of my
married brother, and, like an excellent grandfather, brought up the
children. We had the sorrow of losing him in 1902, when he had just
passed seventy.

So it was in November, 1891, at the age of twenty-four, that I was able
to realize the dream that had been always present in my mind for several
years.

When I arrived in Paris I was affectionately welcomed by my sister and
brother-in-law, but I stayed with them only for a few months, for they
lived in one of the outside quarters of Paris where my brother-in-law
was beginning a medical practice, and I needed to get nearer to the
schools. I was finally installed, like many other students of my
country, in a modest little room for which I gathered some furniture. I
kept to this way of living during the four years of my student life.

It would be impossible to tell of all the good these years brought to
me. Undistracted by any outside occupation, I was entirely absorbed in
the joy of learning and understanding. Yet, all the while, my living
conditions were far from easy, my own funds being small and my family
not having the means to aid me as they would have liked to do. However,
my situation was not exceptional; it was the familiar experience of many
of the Polish students whom I knew. The room I lived in was in a garret,
very cold in winter, for it was insufficiently heated by a small stove
which often lacked coal. During a particularly rigorous winter, it was
not unusual for the water to freeze in the basin in the night; to be
able to sleep I was obliged to pile all my clothes on the bedcovers. In
the same room I prepared my meals with the aid of an alcohol lamp and a
few kitchen utensils. These meals were often reduced to bread with a cup
of chocolate, eggs or fruit. I had no help in housekeeping and I myself
carried the little coal I used up the six flights.

This life, painful from certain points of view, had, for all that, a
real charm for me. It gave me a very precious sense of liberty and
independence. Unknown in Paris, I was lost in the great city, but the
feeling of living there alone, taking care of myself without any aid,
did not at all depress me. If sometimes I felt lonesome, my usual state
of mind was one of calm and great moral satisfaction.

All my mind was centered on my studies, which, especially at the
beginning, were difficult. In fact, I was insufficiently prepared to
follow the physical science course at the Sorbonne, for, despite all my
efforts, I had not succeeded in acquiring in Poland a preparation as
complete as that of the French students following the same course. So I
was obliged to supply this deficiency, especially in mathematics. I
divided my time between courses, experimental work, and study in the
library. In the evening I worked in my room, sometimes very late into
the night. All that I saw and learned that was new delighted me. It was
like a new world opened to me, the world of science, which I was at last
permitted to know in all liberty.

I have pleasant memories of my relations with my student companions.
Reserved and shy at the beginning, it was not long before I noticed that
the students, nearly all of whom worked seriously, were disposed to be
friendly. Our conversations about our studies deepened our interest in
the problems we discussed.

Among the Polish students I did not have any companions in my studies.
Nevertheless, my relations with their small colony had a certain
intimacy. From time to time we would gather in one another's bare rooms,
where we could talk over national questions and feel less isolated. We
would also go for walks together, or attend public reunions, for we were
all interested in politics. By the end of the first year, however, I was
forced to give up these relationships, for I found that all my energy
had to be concentrated on my studies, in order to achieve them as soon
as possible. I was even obliged to devote most of my vacation time to
mathematics.

My persistent efforts were not in vain. I was able to make up for the
deficiency of my training and to pass examinations at the same time with
the other students. I even had the satisfaction of graduating in first
rank as "_licenciée es sciences physiques_" in 1893, and in second rank
as "_licenciée es sciences mathématiques_" in 1894.

My brother-in-law, recalling later these years of work under the
conditions I have just described, jokingly referred to them as "the
heroic period of my sister-in-law's life." For myself, I shall always
consider one of the best memories of my life that period of solitary
years exclusively devoted to the studies, finally within my reach, for
which I had waited so long.

It was in 1894 that I first met Pierre Curie. One of my compatriots, a
professor at the University of Fribourg, having called upon me, invited
me to his home, with a young physicist of Paris, whom he knew and
esteemed highly. Upon entering the room I perceived, standing framed by
the French window opening on the balcony, a tall young man with auburn
hair and large, limpid eyes. I noticed the grave and gentle expression
of his face, as well as a certain abandon in his attitude, suggesting
the dreamer absorbed in his reflections. He showed me a simple
cordiality and seemed to me very sympathetic. After that first interview
he expressed the desire to see me again and to continue our conversation
of that evening on scientific and social subjects in which he and I were
both interested, and on which we seemed to have similar opinions.

Some time later, he came to me in my student room and we became good
friends. He described to me his days, filled with work, and his dream of
an existence entirely devoted to science. He was not long in asking me
to share that existence, but I could not decide at once; I hesitated
before a decision that meant abandoning my country and my family.

I went back to Poland for my vacation, without knowing whether or not I
was to return to Paris. But circumstances permitted me again to take up
my work there in the autumn of that year. I entered one of the physics
laboratories at the Sorbonne, to begin experimental research in
preparation for my doctor's thesis.

Again I saw Pierre Curie. Our work drew us closer and closer, until we
were both convinced that neither of us could find a better life
companion. So our marriage was decided upon and took place a little
later, in July, 1895.

Pierre Curie had just received his doctor's degree and had been made
professor in the School of Physics and Chemistry of the City of Paris.
He was thirty-six years old, and already a physicist known and
appreciated in France and abroad. Solely preoccupied with scientific
investigation, he had paid little attention to his career, and his
material resources were very modest. He lived at Sceaux, in the suburbs
of Paris, with his old parents, whom he loved tenderly, and whom he
described as "exquisite" the first time he spoke to me about them. In
fact, they were so: the father was an elderly physician of high
intellect and strong character, and the mother the most excellent of
women, entirely devoted to her husband and her sons. Pierre's elder
brother, who was then professor at the University of Montpellier, was
always his best friend. So I had the privilege of entering into a family
worthy of affection and esteem, and where I found the warmest welcome.

We were married in the simplest way. I wore no unusual dress on my
marriage day, and only a few friends were present at the ceremony, but
I had the joy of having my father and my second sister come from Poland.

We did not care for more than a quiet place in which to live and to
work, and were happy to find a little apartment of three rooms with a
beautiful view of a garden. A few pieces of furniture came to us from
our parents. With a money gift from a relative we acquired two bicycles
to take us out into the country.




CHAPTER II


With my marriage there began for me a new existence entirely different
from the solitary life that I had known during the preceding years. My
husband and I were so closely united by our affection and our common
work that we passed nearly all of our time together. I have only a few
letters from him, for we were so little apart. My husband spent all the
time he could spare from his teaching at his research work in the
laboratory of the school in which he was professor and I obtained
authorization to work with him.

Our living apartment was near the school, so we lost little time in
going and coming. As our material resources were limited, I was obliged
to attend to most of the housekeeping myself, particularly the
preparation of meals. It was not easy to reconcile these household
duties with my scientific work, yet, with good will, I managed it. The
great thing was that we were alone together in the little home which
gave us a peace and intimacy that were very enjoyable for us.

At the same time that I was working in the laboratory, I still had to
take a few study courses, for I had decided to take part in the
examination for a certificate that would allow me to teach young girls.
If I succeeded in this, I would be entitled to be named professor. In
August, 1896, after having devoted several months to preparation, I came
out first in the examination.

Our principal distraction from the close work of the laboratory
consisted in walks or bicycle rides in the country. My husband greatly
enjoyed the out-of-doors and took great interest in the plants and
animals of woods and meadows. Hardly a corner in the vicinity of Paris
was unknown to him. I also loved the country and these excursions were a
great joy for me as well as to him, relieving our mind from the tension
of the scientific work. We used to bring home bunches of flowers.
Sometimes we forgot all about the time and got back late at night. We
visited regularly my husband's parents where our room was always ready.

In the vacation we went on longer outings by means of our bicycles. In
this way we covered much ground in Auvergne and in the Cevennes and
visited several regions at the seashore. We took a great delight in
these long all-day excursions, arriving at night always in a new place.
If we stayed in one place too long, my husband began to wish to get back
to the laboratory. It is also in vacation time that we visited once my
family in the Carpathian mountains. My husband learned some Polish in
view of this journey to Poland.

But first of all in our life was our scientific work. My husband gave
much care to the preparation of his courses, and I gave him some
assistance in this, which, at the time, helped me in my education.
However, most of our time was devoted to our laboratory researches.

My husband did not then have a private laboratory. He could, to some
extent, use the laboratory of the school for his own work, but found
more freedom by installing himself in some unused corner of the Physics
School building. I thus learned from his example that one could work
happily even in very insufficient quarters. At this time my husband was
occupied with researches on crystals, while I undertook an investigation
of the magnetic properties of steel. This work was completed and
published in 1897.

In that same year the birth of our first daughter brought a great change
in our life. A few weeks later my husband's mother died and his father
came to live with us. We took a small house with a garden at the border
of Paris and continued to occupy this house as long as my husband lived.

It became a serious problem how to take care of our little Irene and of
our home without giving up my scientific work. Such a renunciation would
have been very painful to me, and my husband would not even think of it;
he used to say that he had got a wife made expressly for him to share
all his preoccupations. Neither of us would contemplate abandoning what
was so precious to both.

Of course we had to have a servant, but I personally saw to all the
details of the child's care. While I was in the laboratory, she was in
the care of her grandfather, who loved her tenderly and whose own life
was made brighter by her. So the close union of our family enabled me to
meet my obligations. Things were particularly difficult only in case of
more exceptional events, such as a child's illness, when sleepless
nights interrupted the normal course of life.

It can be easily understood that there was no place in our life for
worldly relations. We saw but a few friends, scientific workers, like
ourselves, with whom we talked in our home or in our garden, while I did
some sewing for my little girl. We also maintained affectionate
relations with my husband's brother and his family. But I was separated
from all my relatives, as my sister had left Paris with her husband to
live in Poland.

It was under this mode of quiet living, organized according to our
desires, that we achieved the great work of our lives, work begun about
the end of 1897 and lasting for many years.

I had decided on a theme for my doctorate. My attention had been drawn
to the interesting experiments of Henri Becquerel on the salts of the
rare metal uranium. Becquerel had shown that by placing some uranium
salt on a photographic plate, covered with black paper, the plate would
be affected as if light had fallen on it. The effect is produced by
special rays which are emitted by the uranium salt and are different
from ordinary luminous rays as they can pass through black paper.
Becquerel also showed that these rays can discharge an electroscope. He
at first thought that the uranium rays were produced as a result of
exposing the uranium salt to light, but experiment showed that salts
kept for several months in the dark continued the peculiar rays.

My husband and I were much excited by this new phenomenon, and I
resolved to undertake the special study of it. It seemed to me that the
first thing to do was to measure the phenomenon with precision. In this
I decided to use that property of the rays which enabled them to
discharge an electroscope. However, instead of the usual electroscope, I
used a more perfect apparatus. One of the models of the apparatus used
by me for these first measurements is now in the College of Physicians
and Surgeons in Philadelphia.

I was not long in obtaining interesting results. My determinations
showed that the emission of the rays is an atomic property of the
uranium, whatever the physical or chemical conditions of the salt were.
Any substance containing uranium is as much more active in emitting
rays, as it contains more of this element.

I then thought to find out if there were other substances possessing
this remarkable property of uranium, and soon found that substances
containing thorium behaved in a similar way, and that this behavior
depended similarly on an atomic property of thorium. I was now about to
undertake a detailed study of the uranium and thorium rays when I
discovered a new interesting fact.

I had occasion to examine a certain number of minerals. A few of them
showed activity; they were those containing either uranium or thorium.
The activity of these minerals would have had nothing astonishing about
it, if it had been in proportion to the quantities of uranium or thorium
contained in them. But it was not so. Some of these minerals revealed an
activity three or four times greater than that of uranium. I verified
this surprising fact carefully, and could not doubt its truth.
Speculating about the reason for this, there seemed to be but one
explanation. There must be, I thought, some unknown substance, very
active, in these minerals. My husband agreed with me and I urged that we
search at once for this hypothetical substance, thinking that, with
joined efforts, a result would be quickly obtained. Neither of us could
foresee that in beginning this work we were to enter the path of a new
science which we should follow for all our future.

Of course, I did not expect, even at the beginning, to find a new
element in any large quantity, as the minerals had already been analyzed
with some precision. At least, I thought there might be as much as one
per cent of the unknown substance in the minerals. But the more we
worked, the clearer we realized that the new radioactive element could
exist only in quite minute proportion and that, in consequence, its
activity must be very great. Would we have insisted, despite the
scarcity of our means of research, if we had known the true proportion
of what we were searching for, no one can tell; all that can be said now
is that the constant progress of our work held us absorbed in a
passionate research, while the difficulties were ever increasing. As a
matter of fact, it was only after several years of most arduous labor
that we finally succeeded in completely separating the new substance,
now known to everybody as radium. Here is, briefly, the story of the
search and discovery.

As we did not know, at the beginning, any of the chemical properties of
the unknown substance, but only that it emits rays, it was by these rays
that we had to search. We first undertook the analysis of a pitchblende
from St. Joachimsthal. Analyzing this ore by the usual chemical methods,
we added an examination of its different parts for radioactivity, by the
use of our delicate electrical apparatus. This was the foundation of a
new method of chemical analysis which, following our work, has been
extended, with the result that a large number of radioactive elements
have been discovered.

In a few weeks we could be convinced that our prevision had been right,
for the activity was concentrating in a regular way. And, in a few
months, we could separate from the pitchblende a substance accompanying
the bismuth, much more active than uranium, and having well defined
chemical properties. In July, 1898, we announced the existence of this
new substance, to which I gave the name of polonium, in memory of my
native country.

While engaged in this work on polonium, we had also discovered that,
accompanying the barium separated from the pitchblende, there was
another new element. After several months more of close work we were
able to separate this second new substance, which was afterwards shown
to be much more important than polonium. In December, 1898, we could
announce the discovery of this new and now famous element, to which we
gave the name of radium.

However, the greatest part of the material work had yet to be done. We
had, to be sure, discovered the existence of the remarkable new
elements, but it was chiefly by their radiant properties that these new
substances were distinguished from the bismuth and barium with which
they were mixed in minute quantities. We had still to separate them as
pure elements. On this work we now started.

We were very poorly equipped with facilities for this purpose. It was
necessary to subject large quantities of ore to careful chemical
treatment. We had no money, no suitable laboratory, no personal help for
our great and difficult undertaking. It was like creating something out
of nothing, and if my earlier studying years had once been called by my
brother-in-law the heroic period of my life, I can say without
exaggeration that the period on which my husband and I now entered was
truly the heroic one of our common life.

We knew by our experiments that in the treatment of pitchblende at the
uranium plant of St. Joachimsthal, radium must have been left in the
residues, and, with the permission of the Austrian government, which
owned the plant, we succeeded in securing a certain quantity of these
residues, then quite valueless,--and used them for extraction of radium.
How glad I was when the sacks arrived, with the brown dust mixed with
pine needles, and when the activity proved even greater than that of the
primitive ore! It was a stroke of luck that the residues had not been
thrown far away or disposed of in some way, but left in a heap in the
pine wood near the plant. Some time later, the Austrian government, on
the proposition of the Academy of Science of Vienna, let us have several
tons of similar residues at a low price. With this material was prepared
all the radium I had in my laboratory up to the date when I received the
precious gift from the American women.

The School of Physics could give us no suitable premises, but for lack
of anything better, the Director permitted us to use an abandoned shed
which had been in service as a dissecting room of the School of
Medicine. Its glass roof did not afford complete shelter against rain;
the heat was suffocating in summer, and the bitter cold of winter was
only a little lessened by the iron stove, except in its immediate
vicinity. There was no question of obtaining the needed proper apparatus
in common use by chemists. We simply had some old pine-wood tables with
furnaces and gas burners. We had to use the adjoining yard for those of
our chemical operations that involved producing irritating gases; even
then the gas often filled our shed. With this equipment we entered on
our exhausting work.

Yet it was in this miserable old shed that we passed the best and
happiest years of our life, devoting our entire days to our work. Often
I had to prepare our lunch in the shed, so as not to interrupt some
particularly important operation. Sometimes I had to spend a whole day
mixing a boiling mass with a heavy iron rod nearly as large as myself. I
would be broken with fatigue at the day's end. Other days, on the
contrary, the work would be a most minute and delicate fractional
crystallization, in the effort to concentrate the radium. I was then
annoyed by the floating dust of iron and coal from which I could not
protect my precious products. But I shall never be able to express the
joy of the untroubled quietness of this atmosphere of research and the
excitement of actual progress with the confident hope of still better
results. The feeling of discouragement that sometimes came after some
unsuccessful toil did not last long and gave way to renewed activity. We
had happy moments devoted to a quiet discussion of our work, walking
around our shed.

One of our joys was to go into our workroom at night; we then perceived
on all sides the feebly luminous silhouettes of the bottles or capsules
containing our products. It was really a lovely sight and one always new
to us. The glowing tubes looked like faint, fairy lights.

Thus the months passed, and our efforts, hardly interrupted by short
vacations, brought forth more and more complete evidence. Our faith grew
ever stronger, and our work being more and more known, we found means to
get new quantities of raw material and to carry on some of our crude
processes in a factory, allowing me to give more time to the delicate
finishing treatment.

At this stage I devoted myself especially to the purification of the
radium, my husband being absorbed by the study of the physical
properties of the rays emitted by the new substances. It was only after
treating one ton of pitchblende residues that I could get definite
results. Indeed we know to-day that even in the best minerals there are
not more than a few decigrammes of radium in a ton of raw material.

At last the time came when the isolated substances showed all the
characters of a pure chemical body. This body, the radium, gives a
characteristic spectrum, and I was able to determine for it an atomic
weight much higher than that of the barium. This was achieved in 1902. I
then possessed one decigramme of very pure radium chloride. It had taken
me almost four years to produce the kind of evidence which chemical
science demands, that radium is truly a new element. One year would
probably have been enough for the same purpose, if reasonable means had
been at my disposal. The demonstration that cost so much effort was the
basis of the new science of radioactivity.

In later years I was able to prepare several decigrammes of pure radium
salt, to make a more accurate determination of the atomic weight and
even to isolate the pure radium metal. However, 1902 was the year in
which the existence and character of radium were definitely established.

We had been able to live for several years entirely engrossed in the
work of research, but gradually circumstances changed. In 1900 my
husband was offered a professorship in the University of Geneva, but
almost simultaneously he obtained a position of assistant professor at
the Sorbonne, and I was made professor at the Normal Superior School for
young girls at Sèvres. So we remained in Paris.

I became much interested in my work in the Normal School, and endeavored
to develop more fully the practical laboratory exercises of the pupils.
These pupils were girls of about twenty years who had entered the school
after severe examination and had still to work very seriously to meet
the requirements that would enable them to be named professors in the
lycées. All these young women worked with great eagerness, and it was a
pleasure for me to direct their studies in physics.

But a growing notoriety, because of the announcement of our discoveries,
began to trouble our quiet work in the laboratory, and, little by
little, life became more difficult. In 1903 I finished my doctor's
thesis and obtained the degree. At the end of the same year the Nobel
prize was awarded jointly to Becquerel, my husband and me for the
discovery of radioactivity and new radioactive elements.

This event greatly increased the publicity of our work. For some time
there was no more peace. Visitors and demands for lectures and articles
interrupted every day.

The award of the Nobel prize was a great honor. It is also known that
the material means provided by this prize was much greater than is usual
in prizes for science. This was a great help in the continuation of our
researches. Unhappily, we were overtired and had a succession of
failures of health for the one or the other of us, so that it was not
until 1905 that we were able to go to Stockholm, where my husband gave
his Nobel lecture and where we were well received.

The fatigue resulting from the effort exceeding our forces, imposed by
the unsatisfactory conditions of our labor, was augmented by the
invasion of publicity. The overturn of our voluntary isolation was a
cause of real suffering for us and had all the effect of disaster. It
was serious trouble brought into the organization of our life, and I
have already explained how indispensable was our freedom from external
distraction, in order to maintain our family life and our scientific
activity. Of course, people who contribute to that kind of trouble
generally mean it kindly. It is only that they do not realize the
conditions of the problem.

In 1904 our second daughter. Eve Denise, came to us. I had, of course,
to interrupt my work in the laboratory for a while. In the same year,
because of the awarding of the Nobel prize and the general public
recognition, a new chair of physics was created in Sorbonne, and my
husband was named as its occupant. At the same time I was named chief of
work in the laboratory that was to be created for him. But in reality
the laboratory was not constructed then, and only a few rooms taken from
other uses were available to us.

In 1906 just as we were definitely giving up the old shed laboratory
where we had been so happy, there came the dreadful catastrophe which
took my husband away from me and left me alone to bring up our children
and, at the same time, to continue our work of research.

It is impossible for me to express the profoundness and importance of
the crisis brought into my life by the loss of the one who had been my
closest companion and best friend. Crushed by the blow, I did not feel
able to face the future. I could not forget, however, what my husband
used sometimes to say, that, even deprived of him, I ought to continue
my work.

The death of my husband, coming immediately after the general knowledge
of the discoveries with which his name is associated, was felt by the
public, and especially by the scientific circles, to be a national
misfortune. It was largely under the influence of this emotion that the
Faculty of Sciences of Paris decided to offer me the chair, as
professor, which my husband had occupied only one year and a half in the
Sorbonne. It was an exceptional decision, as up to then no woman had
held such a position. The University by doing this offered me a precious
mark of esteem and gave me opportunity to pursue the researches which
otherwise might have had to be abandoned. I had not expected a gift of
this kind; I never had any other ambition than to be able to work freely
for science. The honor that now came to me was deeply painful under the
cruel circumstances of its coming. Besides I wondered whether I would be
able to face such a grave responsibility. After much hesitation, I
decided that I ought at least to try to meet the task, and so I began in
1906 my teaching in the Sorbonne, as assistant professor, and two years
later I was named titular professor.

In my new situation the difficulties of my life were considerably
augmented, as I alone had now to carry the burden formerly weighing on
my husband and me together. The cares of my young children required
close vigilance; in this, my husband's father, who continued to live
with us, willingly took his share. He was happy to be occupied with the
little girls, whose company was his chief consolation after his son's
death. By his effort and mine, the children had a bright home, even if
we lived with our inner grief, which they were too young to realize. The
strong desire of my father-in-law being to live in the country, we took
a house with a garden in Sceaux, a suburb of Paris, from which I could
reach the city in half an hour.

This country life had great advantages, not only for my father-in-law,
who enjoyed his new surroundings, and especially his garden, but also
for my girls, who had the benefit of walks in the open country. But they
were more separated from me, and it became necessary to have a governess
for them. This position was filled first by one of my cousins, and then
by a devoted woman who had already brought up the daughter of one of my
sisters. Both of them were Polish, and in this way my daughters learned
my native tongue. From time to time, some one of my Polish family came
to see me in my grief, and we managed to meet in vacation time, at the
seashore in France, and once in the mountains of Poland.

In 1910 we suffered the loss of my very dear father-in-law, after a long
illness, which brought me many sorrowful days. I used to spend at his
bedside as much time as I could, listening to his remembrances of passed
years. His death affected deeply my elder daughter, who, at twelve, knew
the value of the cheerful hours spent in his company.

There were few resources for the education of my daughters in Sceaux.
The youngest one, a small child, needed principally a hygienic life,
outdoor walks and quite elementary schooling. She had already shown a
vivid intelligence and an unusual disposition for music. Her elder
sister resembled her father in the form of her intelligence. She was not
quick, but one could already see that she had a gift of reasoning power
and that she would like science. She had some training in a private
school in Paris, but I had not wanted to keep her in a lycée, as I have
always found the class hours in these schools too long for the health of
the children.

My view is that in the education of children the requirement of their
growth and physical evolution should be respected, and that some time
should be left for their artistic culture. In most schools, as they
exist to-day, the time spent in various reading and writing exercises is
too great, and the study required to be done at home too much. I also
find these schools lacking, in general, in practical exercises to
accompany the scientific studies.

With a few friends in the university circle who shared these views, we
organized, therefore, a cooperative group for the education of our
children, each of us taking charge of the teaching of a particular
subject to all of the young people. We were all very busy with other
things, and the children varied in age. Nevertheless, the little
experiment thus made was very interesting. With a small number of
classes we yet succeeded in reuniting the scientific and literary
elements of a desirable culture. The courses in science were accompanied
by practical exercises in which the children took great interest.

This arrangement, which lasted two years, proved to be very beneficial
for most of the children; it was certainly so for my elder daughter.
Following this preparation, she was able to enter a higher class in one
of the _collèges_ of Paris, and had no difficulty in passing her
bachelor's examination before the usual age, after which she continued
her scientific studies in the Sorbonne.

My second daughter, although not benefiting by a similar arrangement for
her earlier studies, at first followed the classes of a _collège_ only
partially, and later completely. She showed herself a good pupil, doing
satisfactory work in all directions.

I wanted very much to assure for my children a rational physical
education. Next to outdoor walks, I attach a great importance to
gymnastics and sports. This side of a girl's education is still rather
neglected in France. I took care that my children did gymnastics
regularly. I was also careful to have them spend vacations either in the
mountains or at the seashore. They can canoe and swim very well and are
not afraid of a long walk or a bicycle ride.

But of course the care of my children's education was only a part of my
duties, my professional occupations taking most of my time. I have been
frequently questioned, especially by women, how I could reconcile family
life with a scientific career. Well, it has not been easy; it required a
great deal of decision and of self-sacrifice. However, the family bond
has been preserved between me and my now grown-up daughters, and life is
made brighter by the mutual affection and understanding in our home,
where I could not suffer a harsh word or selfish behavior.

In 1906, when I succeeded my husband at the Sorbonne, I had only a
provisional laboratory with little space and most limited equipment. A
few scientists and students had already been admitted to work there with
my husband and me. With their help, I was able to continue the course of
research with good success.

In 1907, I received a precious mark of sympathy from Mr. Andrew
Carnegie, who donated to my laboratory an annual income for research
fellowships which enabled some advanced students or scientists to devote
their whole time to investigation. Such foundations are very encouraging
to those whose inclinations and talents are such as to warrant their
entire devotion to research work. They ought to be multiplied in the
interest of science.

As for myself, I had to devote again a great deal of time to the
preparation of several decigrammes of very pure radium chloride. With
this I achieved, in 1907, a new determination of the atomic weight of
radium, and in 1910 I was able to isolate the metal. The operation, an
extremely delicate one, was performed with the assistance of a
distinguished chemist belonging to the laboratory staff. It has never
been repeated since that time, because it involves a serious danger of
loss of radium, which can be avoided only with utmost care. So I saw at
last the mysterious white metal, but could not keep it in this state,
for it was required for further experiments.

As for the polonium, I have not been able to isolate it, its quantity in
the mineral being even much less than the quantity of radium. However,
very concentrated polonium has been prepared in my laboratory, and
important experiments have been performed with this substance,
concerning especially the production of helium by radiation of polonium.

I had to devote special care to the improvement of the measuring methods
in the laboratory. I have told how important precise measurements were
in the discovery of radium. It is still to be hoped that efficient
methods of quantitative determination may lead to new discoveries.

I devised a very satisfactory method for determining the quantity of
radium by the means of a radioactive gas produced by it and called
"emanation." This method, frequently used in my laboratory, permits of
the measurement of very small quantities of radium (less than a
thousandth of a milligramme), with a fair precision. More important
quantities are often measured by their penetrating radiation, named
Gamma-rays. For this we also possess in my laboratory a suitable
equipment. It is easier and more satisfactory to measure the radium by
the emitted rays, than to weigh it in a balance. However, these
measurements require the disposition of reliable standards. So the
question of a radium standard had to be taken into careful
consideration.

The measurements of radium had to be established on a solid basis, for
the benefit of laboratories and scientific research, which, of course,
is in itself an important reason, and moreover, the growing medical
utilization of this substance made it necessary to control the relative
purity of commercially produced radium.

The first experiments on the biological properties of radium were
successfully made in France with samples from our laboratory, while my
husband was living. The results were, at once, encouraging, so that the
new branch of medical science, called radiumtherapy (in France,
_Curietherapy_), developed rapidly, first in France and later in other
countries. To supply the radium wanted for this purpose, a
radium-producing industry was established. The first plant was created
in France and worked very successfully, but afterwards manufactures were
founded in other countries, the most important of which are now in
America, where great quantities of radium ore, named "carnotite," are
available. The radiumtherapy and the radium production developed
conjointly, and the results were more and more important, for the
treatment of several diseases, and particularly of cancer. As a
consequence of this, several institutes have been founded, in the large
cities, for the application of the new therapy. Some of these institutes
own several grammes of radium, the commercial price of the gramme being
now about $70,000, the cost of production depending on the very small
proportion of radium in the ore.

It may be easily understood how deeply I appreciated the privilege of
realizing that our discovery had become a benefit to mankind, not only
through its great scientific importance, but also by its power of
efficient action against human suffering and terrible disease. This was
indeed a splendid reward for our years of hard toil.

The success of the therapy depends, of course, on the precise knowledge
of the quantity of radium which is used, so that the measurements of
radium are as important for industry and for medicine as for
physicochemical research.

Considering all these needs, a commission of scientific men of different
countries was formed who agreed to take as a base an international
standard, formed of a carefully weighed quantity of pure radium salt.
Secondary standards were then to be prepared for each country, and
compared to the basic standard by means of their radiation. I was
appointed to prepare the primary standard.

This was a very delicate operation, as the weight of the standard
sample, quite small (about 21 milligrammes of chloride), had to be
determined with great precision. I performed the preparation in 1911.
The standard is a thin glass tube, of a few centimeters in length,
containing the pure salt which was used for the determination of atomic
weight. It was accepted by the Commission and is deposited in the
International Bureau of Weights and Measures at Sèvres, near Paris.
Several secondary standards, compared with the primary one, have been
put into service by the Commission. In France the control of radium
tubes, by the measurement of their radiation, takes place in my
laboratory, where any one may bring the radium to be tested; in the
United States this is done in the Bureau of Standards.

Near the end of the year 1910, I was proposed for the decoration of the
Légion of Honor. A similar proposal was made earlier in favor of my
husband, who, however, being opposed to all honorary distinctions, did
not accept the nomination. As my husband and I were too united in all
things for me to act differently from him in this matter, I did not
accept the decoration, in spite of the insistence of the Ministry. At
that time also, several colleagues persuaded me to be a candidate for
election to the Academy of Sciences of Paris, of which my husband was a
member during the last months of his life. I hesitated very much, as
such a candidacy requires, by custom, a great number of personal visits
to Academy members. However, I consented to offer myself a candidate,
because of the advantages an election would have for my laboratory. My
candidacy provoked a vivid public interest, especially because it
involved the question of the admission of women to the Academy. Many of
the Academicians were opposed to this in principle, and when the
scrutiny was made, I had a few votes less than was necessary. I do not
ever wish to renew my candidacy, because of my strong distaste for the
personal solicitation required. I believe that all such elections should
be based wholly on a spontaneous decision, without any personal efforts
involved, as was the case for several Academies and Societies which made
me a member without any demand or initiative on my part.

As a result of all the cares devolving on me, I fell seriously ill at
the end of 1911, when, for the second time, I received, this time alone,
the award of the Nobel prize. This was a very exceptional honor, a high
recognition of the discovery of the new elements and of the preparation
of pure radium. Suffering though I was, I went to Stockholm to receive
the prize. The journey was extremely painful for me. I was accompanied
by my eldest sister and my young daughter Irene. The ceremony of
delivery of the Nobel prizes is very impressive, having the features of
a national solemnity. A most generous reception was accorded me,
specially by the women of Sweden. This was a great comfort to me, but I
was suffering so much that when I returned I had to stay in bed for
several months. This grave illness, as well as the necessities of my
children's education, obliged me to move my home from Sceaux to Paris.

During the year 1912 I had the opportunity of collaborating in the
creation of a laboratory of radium at Warsaw. This laboratory was
founded by the Scientific Society of Warsaw which offered me its
direction. I could not leave France to go back to my native country, but
I willingly agreed to occupy myself with the organization of the studies
in the new laboratory. In 1913, having improved my health, I was able to
attend an inauguration fête in Warsaw, where a touching reception was
given, leaving me an unforgettable memory of national sentiment which
succeeded in creating useful work under particularly difficult political
conditions.

While still only partially recovered from my illness, I renewed my
efforts for the construction of a suitable laboratory in Paris. Finally
it was arranged for, and work began in 1912. The Pasteur Institute
wished to be associated with this laboratory, and, in accord with the
University, it was decided to create an Institute of Radium, with two
laboratories, one of physics and one of biology, the first to be devoted
to studies of the physical and chemical properties of the radioactive
elements, the second to the study of their biological and medical
applications. But, because of the lack of financial means, the
construction work proceeded very slowly, and was not yet entirely
finished when the war broke out in 1914.




CHAPTER III


In 1914, it happened, as it often had in other years, that my daughters
had left Paris for their summer vacation before me. They were
accompanied by their governess, in whom I had all confidence, and were
living in a small house on the seashore in Brittany, at a place where
there were also the families of several of our good friends. My work did
not generally permit me to pass the entire vacation near them without
interruption.

That year I was preparing to join them in the last days of July, when I
was stopped by the bad political news, with its premonitions of an
imminent military mobilization. It did not seem possible for me to leave
under these conditions, and I waited for further events. The
mobilization was announced on August 1st, immediately followed by
Germany's declaration of war on France. The few men of the laboratory
staff and the students were mobilized, and I was left alone with our
mechanic who could not join the army because of a serious heart trouble.

The historic events that followed are known to every one, but only those
who lived in Paris through the days of August and September, 1914, can
ever really know the state of mind in the capital and the quiet courage
shown by it. The mobilization was a general wave of all France passing
out to the border for the defense of the land. All our interest now
centered on the news from the front.

After the uncertainties of the first days this news became more and more
grave.

First, it was the invasion of Belgium and the heroic resistance of that
little country; then the victorious march of the German army through the
valley of the Oise toward Paris; and soon the departure of the French
government to Bordeaux, followed by the leaving of those Parisians who
could not, or would not, face the possible danger of German occupation.
The overloaded trains took into the country a great number of people,
mostly of the well-to-do class. But, on the whole, the people of Paris
gave a strong impression of calm and quiet decision in that fateful year
of 1914. In the end of August and the beginning of September the weather
was radiant, and under the glorious sky of those days the great city
with its architectural treasures seemed to be particularly dear to those
who remained in it.

When the danger of German attack on Paris became pressing, I felt
obliged to put in security the supply of radium then in my laboratory,
and I was charged by the government to take it to Bordeaux for safety.
But I did not want to be away long, and hence decided to return
immediately. I left by one of the trains that were carrying government
staff and baggage, and I well remember the aspect of the national
highway which is at intervals in view from the train; it showed a long
line of motor-cars carrying their owners from the capital.

Arriving at Bordeaux in the evening, I was very embarrassed with my
heavy bag including the radium protected by lead. I was not able to
carry it and waited in a public place, while a friendly ministry
employee who came by the same train managed to find a room for me in a
private apartment, the hotels being overcrowded. The next morning I
hurried to put the radium in a safe place, and succeeded, although not
without difficulty, in taking a military train back to Paris in the
evening of the same day. Having opportunity for exchanging a few
sentences with persons on the place who wanted to ask information from
people coming by the train, I was interested to notice how they seemed
surprised and comforted to learn of some one who found it natural to
return to Paris.

My trip back was troubled by delays; for several hours the train rested
immovable on the rails, while the travelers accepted a little bread from
the soldiers who were provided with it. Finally arriving in Paris, I
learned that the German army had turned; the battle of the Marne had
begun.

In Paris I shared the alternating hope and grief of the inhabitants
during the course of that great battle, and had the constant worry of
foreseeing a long separation from my children in case the Germans
succeeded in occupying the city. Yet I felt that I must stay at my post.
After the successful outcome of the battle, however, any immediate
danger of occupation being removed, I was able to have my daughters come
back from Brittany to Paris and again take up their studies. This was
the great desire of my children, who did not want to stay away from me
and from their work, even if many other families thought it wiser to
stay in the country, far from the front.

The dominant duty imposed on every one at that time was to help the
country in whatever way possible during the extreme crisis that it
faced. No general instructions to this were given to the members of the
University. It was left to each to take his own initiative and means of
action. I therefore sought to discover the most efficient way to do
useful work, turning my scientific knowledge to most profit.

During the rapid succession of events in August, 1914, it was clearly
proved that the preparation for defense was insufficient. Public feeling
was especially aroused by the realization of the grave failings which
appeared in the organization of the Health Service. My own attention was
particularly drawn to this situation, and I soon found a field of
activity which, once entered upon, absorbed the greatest part of my time
and efforts until the end of the war, and even for some time thereafter.
The work was the organization of radiologic and radiotherapeutic
services for the military hospitals. But I also had to make the change,
during these difficult war years, of my laboratory into the new building
of the Institute of Radium and to continue, in the measure possible to
me, regular teaching, as well as to investigate certain problems
especially interesting the military service.

It is well known that the X-rays offer surgeons and doctors extremely
useful means for the examination of the sick and wounded. They make
possible the discovery and the exact location of projectiles which have
entered the body, and this is a great help in their extraction. These
rays also reveal lesions of bones and of the internal organs and permit
one to follow the progress of recovery from internal injuries. The use
of the X-rays during the war saved the lives of many wounded men; it
also saved many from long suffering and lasting infirmity. To all the
wounded it gave a greater chance of recovery.

However, at the beginning of the war, the Military Board of Health had
no organization of radiology, while the civil organization was also but
little developed. Radiologic installations existed in only a small
number of important hospitals, and there were only a few specialists in
the large cities. The numerous new hospitals that were established all
over France in the first months of the war had, as a rule, no
installation for the use of X-rays.

To meet this need I first gathered together all the apparatus I could
find in the laboratories and stores. With this equipment I established
in August and September, 1914, several stations of radiology, the
operation of which was assured by volunteer helpers to whom I gave
instruction. These stations rendered great service during the battle of
the Marne. But as they could not satisfy the needs of all the hospitals
of the Paris region, I fitted up, with the help of the Red Cross, a
radiologic car. It was simply a touring motor-car, arranged for the
transport of a complete radiologic apparatus, together with a dynamo
that was worked by the engine of the car, and furnished the electric
current necessary for the production of the rays. This car could come at
the call of any of the hospitals, large or small, in the surroundings of
Paris. Cases of urgent need were frequent, for these hospitals had to
take care of the wounded who could not be transported to more distant
places.

The first results of this work showed that it was necessary to do more.
Thanks to special donations and to the help of a very efficient relief
committee called "le Patronage National des Blessés," I succeeded in
developing my initiative to a considerable extent. About two hundred
radiologic installations were established or materially improved through
my efforts in the zone of the French and Belgian armies, and in the
regions of France not occupied by the army. I was able, besides, to
equip in my laboratory and give to the army twenty radiologic cars. The
frames of these cars were donated by various persons who wished to be
helpful; some of them offered also the equipment. The cars were of the
greatest service to the army.

These privately developed installations were particularly important in
the first two years of the war, when the regular military service
possessed but few radiologic instruments. Later the Board of Health
created, little by little, a considerable radiologic service of its own,
as the utility of the stations was more clearly realized owing to the
example given by private initiative. But the needs of the armies were so
great, that my cooperation continued necessary to the end of the war,
and even afterwards.

I could not have accomplished this work without seeing for myself the
needs of the ambulance stations and hospitals. Thanks to the help of the
Red Cross and to the agreement of the Board of Health, I was able to
make several journeys to the army zones and to the other parts of
France. Several times I visited the ambulance stations of the armies of
the north and in the Belgian zone, going to Amiens, Calais, Dunkirk,
Furnes, and Poperinghe. I went to Verdun, Nancy, Luneville, Belfort, to
Compiegne, and Villers-Cotterets. In the regions distant from the front,
I took care of many hospitals which had to do very intensive work with
little aid. And I keep as a precious recollection of that time, many
letters of warm recognition from those to whom I brought help in their
difficulties.

The motive of my starting on a journey was usually a demand from
surgeons. I went with a radiologic car which I kept for my personal use.
In examining the wounded in the hospital, I could gain information of
the special needs of the region. When back in Paris, I got the necessary
equipment to meet these needs and returned to install it myself, for
very often the people on the ground could not do it. I had then to find
competent persons to handle the apparatus and show them how to do it, in
full detail. After a few days of hard toil, the manipulator knew enough
to work the apparatus himself, and at the same time a large number of
wounded had been examined. In addition, the surgeons of the region had
gained an idea of the usefulness of the radiologic examination (which
few of them knew at that time), and friendly relations were established
which made the later development of my work much easier.

On several of my trips I was accompanied by my elder daughter, Irene,
who was then seventeen years old, and, having finished her preparatory
studies, was beginning higher studies at the Sorbonne. Because she
greatly desired to be useful, she now studied nursing and learned
radiology, and did her best to help me under the most varied
circumstances. She did ambulance work at the front between Furnes and
Ypres, and also at Amiens, receiving, from the Chiefs of Service,
testimonials of work satisfactorily performed and, at the end of the
war, a medal.

Of the hospital life of those years, we keep many a remembrance, my
daughter and I. Traveling conditions were extraordinarily difficult; we
were often not sure of being able to press forward, to say nothing of
the uncertainty of finding lodgings and food. However, things always
ended in arranging themselves, thanks to our persistence and to the good
will we met. Wherever we went I had to look after each detail myself and
see innumerable military chiefs to obtain passes and permissions for
transportation. Many a time I loaded my apparatus on to the train
myself, with the help of the employees, to make sure that it would go
forward instead of remaining behind several days at the station. And on
arrival I also went to extract them from the encumbered station.

When I traveled with the radiologic car, other problems presented
themselves. I had, for instance, to find safe places for the car, to get
lodgings for the assistants and to secure the automobile accessories.
Since chauffeurs were scarce, I learned to drive the car, and did it
when necessary. Owing to all this personal supervision, my installations
were usually swiftly made, whereas appeal to the Central Health Service
was answered slowly. So the military chiefs greatly appreciated the
assistance they could get from me, especially in cases of urgent need.

We both, my daughter and myself, have pleasant and grateful memories of
the personnel of the hospitals, and were on the best terms with the
surgeons and nurses. One could not but admire these men and women who
were giving their services without counting, and whose task was often
overwhelming. Our collaboration was easy, for my daughter and I tried to
work in their spirit; and we felt that we were standing side by side
with friends.

While we were attached to the Belgian Ambulance Service, we were present
several times during visits of King Albert and Queen Elizabeth. We
appreciated deeply their devotion, their solicitude for the wounded,
their extreme simplicity, and the cordiality of their behavior.

But nothing was so moving as to be with the wounded and to take care of
them. We were drawn to them because of their suffering and because of
the patience with which they bore it. Almost everyone did his best to
facilitate the X-ray examination, notwithstanding the pain caused by any
displacement. One learned very soon to know them individually and to
exchange with them a few friendly words. Those who were not familiar
with the examination, wanted very much to be reassured about the effect
of the strange apparatus they were going to experience.

I can never forget the terrible impression of all that destruction of
human life and health. To hate the very idea of war, it ought to be
sufficient to see once what I have seen so many times, all through those
years: men and boys brought to the advanced ambulance in a mixture of
mud and blood, many of them dying of their injuries, many others
recovering but slowly through months of pain and suffering.

One of my difficult problems was to find the necessary trained
assistants to operate my apparatus. At the beginning of the war there
was little knowledge of radiology, and apparatus in the hands of those
who did not understand how to handle it deteriorated quickly and was
soon useless. The practice of radiology in most hospitals in war-time
does not require much medical knowledge; it can be sufficiently grasped
by intelligent persons who know how to study and who have some notion of
electrical machinery. Professors, engineers, or university students
often made good manipulators. I had to look for those who were
temporarily free from military service, or who happened to be stationed
in the locality where I needed them. But even after I had secured them,
these operators were often transferred by military orders, and I had to
search again for others to fill their places. For this reason, I
determined to train women to do this work.

Accordingly, I proposed to the Health Service to add a department of
radiology to the Nurses' School which had just been founded at the Edith
Cavell Hospital. This they agreed to do. And so, in 1916, the course was
organized at the Radium Institute, and provided in the following years
of war for the training of one hundred and fifty operators. Most of the
pupils who applied had only an elementary education, but could succeed
if working in a proper way. The course comprised theoretical studies and
very extended practical training; it included also some instruction in
anatomy. It was given by a few persons of good will, among them my
daughter. Our graduates formed an excellent personnel very genuinely
appreciated by the Board of Health. Theoretically, they were supposed to
serve as aides to physicians, but several of them proved capable of
independent work.

My continued and various experience in war radiology gave me a wide
knowledge of that subject, which I felt should be made more familiar to
the public. So I wrote a small book called "Radiology and the War," in
which I aimed to demonstrate the vital importance of radiology and to
compare its development during war time with its use in the previous
time of peace.

I come now to the account of the founding of the service of
radiumtherapy at the Radium Institute.

In 1915, the radium, which had been safely deposited in Bordeaux, was
brought back to Paris, and not having time for regular scientific
research, I decided to use it to cure the wounded, without, however,
risking the loss of this precious material. I proceeded to place at the
disposal of the Health Service not the radium itself, but the emanation
which can be obtained from it at regular intervals. The technique of the
use of the emanation can readily be employed in the larger radiumtherapy
institutes, and, in many ways, is more practicable than the direct use
of radium. In France, however, there was no national institute of
radiumtherapy, and the emanation was not used in hospitals.

I offered to furnish regularly to the Health Service bulbs of radium
emanation. The offer was accepted, and the "Emanation Service," started
in 1916, was continued until the end of the war and even longer. Having
no assistants, I had, for a long time, to prepare these emanation bulbs
alone, and their preparation is very delicate. Numbers of wounded and
sick, military and civil, were treated by means of these bulbs.

During the bombardment of Paris, the Health Board took special measures
to protect from shells the laboratory in which the bulbs were prepared.
Since the handling of radium is far from being free of danger (several
times I have felt a discomfort which I consider a result of this cause),
measures were taken to prevent harmful effects of the rays on the
persons preparing emanation.

While the work in connection with the hospitals remained my major
interest, I had many other preoccupations during the war.

After the failure of the German offensive in the summer of 1918, at the
request of the Italian government, I went to Italy to study the question
of her natural resources in radioactive materials. I remained a month
and was able to obtain certain results in interesting the public
authorities in the importance of this new subject.

It was in 1915 that I had to move my laboratory to the new building in
the rue Pierre Curie. This was a trying and complicated experience, for
which, once more, I had no money nor any help. So it was only between my
journeys that I was able, little by little, to do the transportation of
my laboratory equipment, in my radiologic cars. Afterwards, I had much
work in classifying and distributing my materials, and arranging the new
place in general, with the help of my daughter and of my mechanic, who,
unfortunately, was often ill.

One of my first cares was to have trees planted in the limited grounds
of my laboratory. I feel it very necessary for the eyes to have the
comfort of fresh leaves in spring and summer time. So I tried to make
things pleasant for those who were to work in the new building. We
planted a few lime trees and plane trees, as many as there was room for,
and did not forget flowerbeds and roses. I well remember the first day
of bombardment of Paris with the big German gun; we had gone, in the
early morning, to the flower-market, and spent all that day busy with
our plantation, while a few shells fell in the vicinity.

In spite of the great difficulties, the new laboratory was organized
little by little, and I had the satisfaction of having it quite ready
for the beginning of the school-year 1919-20, the period of
demobilization. In the spring of 1919, I organized special courses for
some American soldier students, who also studied with much zeal the
practical exercises directed by my daughter.


[Illustration: _Photo by U. S. Signal Corps._

Mme. Curie instructing American soldiers in her Paris laboratory.]


The entire period of the war was for me, as for many others, a period of
great fatigue. I took almost no vacation, except for a few days, now and
then, when I went to see my daughters on their holidays. My older
daughter would scarcely take any, and I was obliged to send her away
sometimes to preserve her health. She was continuing her studies in the
Sorbonne, and besides, as said before, was helping me with my war work,
while the younger daughter was still in the preparatory college. Neither
of them wished to leave Paris during the bombardment.

After more than four years of a war which caused ravages without
precedent, the armistice came at last, in the autumn of 1918, followed
by laborious efforts to reëstablish peace, which is not yet general nor
complete. It was a great relief to France to see the end of that dark
period of cruel losses. But the griefs are too recent and life still too
hard for calm and happiness yet to be restored.

Nevertheless, a great joy came to me as a consequence of the victory
obtained by the sacrifice of so many human lives. I had lived, though I
had scarcely expected it, to see the reparation of more than a century
of injustice that had been done to Poland, my native country, and that
had kept her in slavery, her territories and people divided among her
enemies. It was a deserved resurrection for the Polish nation, which
showed herself faithful to her national memories during the long period
of oppression, almost without hope. The dream that appeared so difficult
to realize, although so dear, became a reality following the storm that
swept over Europe. In these new conditions I went to Warsaw and saw my
family again, after many years of separation, in the capital of free
Poland. But how difficult are the conditions of life of the new Polish
republic, and how complicated is the problem of reorganization after so
many years of abnormal life!

In France, partly devastated and suffering from the loss of so many of
her citizens, the difficulties created by the war are not yet effaced,
and the return to normal work is being attained only gradually. The
scientific laboratories feel this state of affairs and the same
condition prevails for the Radium Institute.

The various radiologic organizations created during the war still
partially exist. The Radiographic Nurses' School has been maintained at
the request of the Board of Health. The emanation service, which could
not be abandoned, is also continued in a considerably enlarged form. It
has passed under the direction of Doctor Regaud, Director of the Pasteur
Laboratory of the Radium Institute, and is developing into a great
national service of radiumtherapy.

The work of the laboratory has been reorganized, with the return of the
mobilized personnel and the students. But in the restrained
circumstances under which the country still exists, the laboratory lacks
ways and means for its efficient development. Particularly are wanted an
independent hospital for radiumtherapy (which is called _Curietherapy_
in France), and an experimental station, outside of Paris, for
experiments on great quantities of material, such as are needed for the
progress of our knowledge of radioactive elements.

I myself am no longer young, and I frequently ask myself whether, in
spite of recent efforts of the government aided by some private
donations, I shall ever succeed in building up for those who will come
after me an Institute of Radium, such as I wish to the memory of Pierre
Curie and to the highest interest of humanity.

However, a precious encouragement came to me in the year 1921. On the
initiative of a generous daughter of the United States, Mrs. W. B.
Meloney, the women of that great American country collected a fund, the
"Marie Curie Radium Fund," and offered me the gift of a gramme of radium
to be placed entirely at my disposal for scientific research. Mrs.
Meloney invited me with my daughters to come to America and to receive
the gift, or the symbol of it, from the hands of the President of the
great republic, at the White House.

The fund was collected by a public subscription, as well by small as by
important gifts, and I was very thankful to my sisters of America for
this genuine proof of their affection. So I started for New York at the
beginning of May, after a ceremony given in my honor at the Opera of
Paris, to greet me before my departing.

I keep a grateful memory of my sojourn in the United States for several
weeks, of the impressive reception at the White House, where President
Harding addressed me in generous and affectionate words, of my visits to
the universities and colleges which welcomed me and bestowed on me their
honorary degrees, of the public reunions where I could not but feel the
deep sympathy of those who came to meet me and to wish me good luck.


[[Illustration: _Henri Manuel, Paris._

Madame Curie in her laboratory at the Institut Curie, Paris.]


I had also the opportunity of a visit to the Niagara Falls and to the
Grand Canyon, and admired immensely these marvelous creations of nature.

Unhappily, the precarious state of my health did not permit of the
complete fulfilment of the general plan established by my visit to
America. However, I saw and learned much, and my daughters enjoyed to a
full extent the opportunities of their unexpected vacation and the pride
in the recognition of their mother's work. We left for Europe at the end
of June, with the real sorrow of parting from excellent friends whom we
would not forget.

I came back to my work, made easier by the precious gift, with an even
stronger desire to carry it forward with renewed courage. But as my aims
are still wanting support in essential parts, I am frequently compelled
to give thought to a very fundamental question concerning the view a
scientist ought to take of his discovery.

My husband, as well as myself, always refused to draw from our discovery
any material profit. We have published, since the beginning, without any
reserve, the process that we used to prepare the radium. We took out no
patent and we did not reserve any advantage in any industrial
exploitation. No detail was kept secret, and it is due to the
information we gave in our publications that the industry of radium has
been rapidly developed. Up to the present time this industry hardly uses
any methods except those established by us. The treatment of the
minerals and the fractional crystallizations are still performed in the
same way, as I did it in my laboratory, even if the material means are
increased.

As for the radium prepared by me out of the ore we managed to obtain in
the first years of our work, I have given it all to my laboratory.

The price of radium is very high since it is found in minerals in very
small quantities, and the profits of its manufacture have been great, as
this substance is used to cure a number of diseases. So it is a fortune
which we have sacrificed in renouncing the exploitation of our
discovery, a fortune that could, after us, have gone to our children.
But what is even more to be considered is the objection of many of our
friends, who have argued, not without reason, that if we had guaranteed
our rights, we could have had the financial means of founding a
satisfactory Institute of Radium, without experiencing any of the
difficulties that have been such a handicap to both of us, and are still
a handicap to me. Yet, I still believe that we have done right.

Humanity, surely, needs practical men who make the best of their work
for the sake of their own interests, without forgetting the general
interest. But it also needs dreamers, for whom the unselfish following
of a purpose is so imperative that it becomes impossible for them to
devote much attention to their own material benefit. No doubt it could
be said that these idealists do not deserve riches since they do not
have the desire for them. It seems, however, that a society well
organized ought to assure to these workers the means for efficient
labor, in a life from which material care is excluded so that this life
may be freely devoted to the service of scientific research.




CHAPTER IV

A VISIT TO AMERICA


My beautiful voyage to the United States of America resulted, as is
known, from the generous initiative of an American woman, Mrs. Meloney,
editor of an important magazine, the _Delineator_, who, having planned
the gift of a gramme of radium to me by her countrywomen, succeeded in a
few months in bringing this plan to execution, and asked me to come over
and receive the gift personally.

The idea was that the gift would come exclusively from the American
women. A committee including several prominent women and distinguished
scientific men received some important gifts, and made an appeal for a
public subscription, to which a great number of women's organizations,
especially colleges and clubs, responded. In many cases gifts came from
persons who had experienced the benefit of radiumtherapy. In this way
was collected the "Marie Curie Radium Fund" of more than one hundred
thousand dollars for the purchase of a gramme of radium. The President
of the United States, Mr. Harding, kindly agreed to deliver the gift in
a ceremony at the White House.

The Committee invited me and my daughters to the United States in May,
and even though it was not vacation time for me, I accepted the
invitation with the consent of the University of Paris.

All care of the voyage was taken away from me. Mrs. Meloney came to
France in time to be present at a manifestation organized on the 28th of
April in favor of the Radium Institute of Paris by the magazine _Je Sais
Tout_, and accompanied by sincere expressions of sympathy for the
American nation. On May 4th, we took passage at Cherbourg on the
_Olympic_ for New York.

The program of my voyage prepared by the Committee seemed very
intimidating. It was announced that I would not only attend the ceremony
at the White House, but also visit many universities and colleges in
several towns. Some of these institutions had contributed to the Fund;
all desired to offer me honors. The vitality and the activity of the
American nation produces programs on a large scale. On the other hand,
the wideness of the country has developed in American citizens the
custom of long travel. But during all that travel I was protected with
the greatest care, in order to lighten as far as possible the inevitable
fatigue of the voyage and the receptions. America not only gave me a
generous welcome, but also true friends whom I could not thank enough
for their kindness and their devotion.

After having admired the grand view of the harbors of New York, and
having been greeted by groups of students, Girl Scouts, and Polish
delegates, and welcomed by many gifts of flowers, we took possession of
a peaceful apartment in town. The following day I made the acquaintance
of the Reception Committee at a luncheon given by Mrs. Carnegie in her
beautiful home still filled with memories of her husband, Andrew
Carnegie, whose philanthropic achievements are well known in France. The
following day we went for a visit of a few days to Smith College, and
Vassar College, a few hours from New York. Later I also visited the
colleges of Bryn Mawr and Wellesley, and I saw some others on my way.

These colleges, or universities for women, are very characteristic of
American life and culture. My short visit could not permit me to give an
authorized opinion on the intellectual training, but even in such a
visit as I made one may notice important differences between the French
and American conception of girls' education, and some of these
differences would not be in favor of our country. Two points have
particularly drawn my attention: the care of the health and the physical
development of the students, and the very independent organization of
their life which allows a large degree of individual initiative.

The colleges are excellent in their construction and organization. They
are composed of several buildings, often scattered in very large grounds
between lawns and trees. Smith is on the shore of a charming river. The
equipment is comfortable and hygienic, of extreme cleanliness, with
bathrooms, showers, distribution of cold and hot water. The students
have cheerful private rooms and common gathering rooms. A very complete
organization of games and sports exists in every college. The students
play tennis and baseball; they have gymnasium, canoeing, swimming, and
horseback riding. Their health is under the constant care of medical
advisers. It seems to be a frequent opinion of American mothers that the
existing atmosphere of cities like New York is not favorable to the
education of young girls, and that a life in the country in the open air
gives more suitable conditions for the health and the tranquillity of
studying.

In every college the young girls form an association and elect a
committee which has to establish the internal rules of the college. The
students display a great activity: they take part in educational work;
they publish a paper; they are devoted to songs and music; they write
plays, and act them in college and out of it. These plays have
interested me very much in their subjects and the execution. The
students are also of different social conditions. Many of them are of
wealthy families, but many others live on scholarships. The whole
organization may be considered as democratic. A few students are
foreigners, and we have met some French students very well pleased with
the college life and the studies.

Every college takes four years of study with examinations from time to
time. Some students afterwards do personal work, and acquire the degree
of Doctor, which does not exactly correspond to the same title in
France. The colleges have laboratories with many good facilities for
experimentation.

I have been strongly impressed by the joy of life animating these young
girls and expanding on every occasion, like that of one of my visit. If
the ceremonies of the reception were performed in a nearly military
order, a spontaneity of youth and happiness expressed itself in the
songs of greeting composed by the students, in the smiling and excited
faces, and in the rushing over the lawns to greet me at my arrival. This
was indeed a charming impression which I could not forget.

Back in New York, several ceremonies awaited me before my leaving for
Washington. A luncheon of the Chemists, a reception at the Museum of
Natural History and the Mineralogical Club, a dinner at the Institute of
Social Sciences, and a great meeting at Carnegie Hall, where many
delegations represented the faculties and students of women's colleges
and universities. At all these receptions I was greeted in warm
addresses by prominent men and women, and I received honors very
precious to me because of the sincerity of the givers. Neither has the
part of national friendships been forgotten; the address of
Vice-President Coolidge was a noble recognition of the past where French
and Polish citizens have been helpful to the young American Republic,
and is also a statement of fraternity strengthened by the tempest of the
last years.

It was in this atmosphere of affection created by the convergence of
intellectual and social sympathies that there took place on May 20th the
beautiful ceremony at the White House. It was a deeply moving ceremony
in all its simplicity, occurring before a democratic gathering including
the President and Mrs. Harding, cabinet officers, Judges of the Supreme
Court, high officers of Army and Navy, foreign diplomats,
representatives of women's clubs and societies, and prominent citizens
of Washington and other cities. It comprised a short presentation by the
French ambassador, M. Jusserand, a speech by Mrs. Meloney for the
American women, the address of President Harding, a few words of
gratitude said by me, a defile of the guests, and a group picture for a
souvenir, all this in the admirable setting of the White House, peaceful
and dignified, white indeed between its green lawns with wide prospects
on that beautiful afternoon of May. A remembrance never to be forgotten
was left by this reception in which the chief representative of a great
nation offered me homage of infinite value, the testimonial of the
recognition of his country's citizens.

The address of the President had been inspired by the same sentiments as
that of Vice-President Coolidge, as far as concerned his appreciation of
France and Poland. This address gave also an expression of the American
feeling which was emphasized by an exceptional solemnity in the
delivering of the gift.


[Illustration: _Copyright International._

Mme. Curie and President Harding at the White House, May 20, 1921, when
a gram of radium was presented to its discoverer by the women of
America.]


The American nation is generous, and always ready to appreciate an
action inspired by considerations of general interest. If the discovery
of radium has so much sympathy in America, it is not only because of its
scientific value, and of the importance of medical utilization; it is
also because the discovery has been given to humanity without
reservation or material benefits to the discoverers. Our American
friends wanted to honor this spirit animating the French science.

The radium itself was not brought to the ceremony. The President
presented me with the symbol of the gift, a small golden key opening the
casket devised for the transportation of the radium.

Our sojourn at Washington following the principal ceremony included a
very agreeable reception at the French Embassy and the Polish Legation,
a reception at the National Museum, and some laboratory visits.

The itinerary of our journey from Washington included visits to the
cities of Philadelphia, Pittsburgh, Chicago, Buffalo, Boston, and New
Haven, a visit to the Grand Canyon, and to Niagara Falls. On that trip I
was the guest of several universities which did me the honor of
bestowing honorary degrees on me. I have to thank for these the
universities of Pennsylvania, of Pittsburgh, of Chicago, the
Northwestern University, Columbia University, Yale University, the
Women's Medical College of Pennsylvania, the University of Pennsylvania,
Smith College, and Wellesley College, while I thank Harvard University
for her reception.

The delivery of honorary degrees in American universities is accompanied
by solemnities. In principle, the presence of the candidate is required,
and the delivery takes place at the annual commencement, but, in some
cases, special ceremonies were organized in my favor. The university
ceremonies in America are more frequent than in France, and play a more
important part in the university life. Especially is this true at the
annual commencement, which begins with an academic procession over the
grounds of the university, the procession including the officials, the
professors, and graduates in academic caps and gowns. Afterwards all
assemble in a hall where are announced the diplomas corresponding to the
grades of bachelor, master, and doctor. There is always a musical part
in the program, and addresses are delivered by the officials of the
university or invited orators. These addresses are naturally devoted to
dignifying the ideals and the humanitarian purposes of education; but in
certain cases it seems permitted to introduced point of American humor.
These ceremonies are on the whole very impressive, and certainly
contribute to keep a bond between the university and the alumni. This is
a favorable circumstance for those great American universities which are
sustained entirely on private foundations. It is only in more recent
times that most States have created universities supported by the State.

At Yale University I had the pleasure of representing the University of
Paris at the inauguration of President Angell, fourteenth president of
the University. I was also pleased to attend at Philadelphia a meeting
of the American Philosophical Society and a meeting of the College of
Physicians, and at Chicago a meeting of the American Chemical Society at
which I delivered a lecture on the Discovery of Radium. The medals of
John Scott, Benjamin Franklin, and Willard Gibbs have been presented to
me by these societies.

Several meetings organized in my honor by the American women's
organizations have particularly interested the American public. I have
already mentioned the meeting of the University Women at Carnegie Hall
of New York; a similar meeting was held at Chicago, where I was also
received by the Association of Polish Women. I was also greeted by
women's organizations in the Carnegie Institute of Pittsburgh, and by a
delegation of Canadian university women at Buffalo. In all these
meetings it was impossible not to recognize the sincerity of the emotion
in the women who gave me their best wishes, at the same time expressing
their confidence in the future of feminine intelligence and activity. I
did not feel any opposition between these feministic aspirations and the
masculine opinion. As far as I could notice, the men in America approve
of these aspirations and encourage them. This is a very favorable
condition for the social activity of the American women which reveals
itself in a strong interest in work for education, for hygiene, and for
the improvement of conditions of labor. But any other unselfish purpose
may rely on their support, as is proved by the success of Mrs. Meloney's
plan, and by the sympathy this plan encountered in women of all social
conditions.

I could not, to my deep regret, give time enough to the visit to
laboratories and scientific institutes. These too brief visits were of
great interest to me. I found everywhere the greatest care for
developing scientific activity and for improving the facilities. New
laboratories are in building, and in older laboratories very modern
equipment may be found. The available room never gives that impression
of insufficiency from which we suffer too often in France. The means are
provided by private initiative expressed in gifts and foundations of
various kinds. There exists also a National Council of Research
established by private funds for stimulating and improving scientific
work, and for assuring its connection with industry.

I have visited with special interest the Bureau of Standards, a very
important national institution at Washington for scientific measurements
and for study connected with them. The tubes of radium presented to me
were at the Bureau, whose officials had kindly offered to make the
measurements, and to take care of the packing and delivery to the ship.

A new laboratory has been created at Washington for researches on very
low temperatures with the use of liquid hydrogen and liquid helium. I
had the honor of dedicating this laboratory to its service.

I had the great pleasure of meeting in their laboratories several very
important American scientific men. The hours I spent in their company
are among the best of my travel.

The United States possesses several hospitals for radiumtherapy. These
hospitals are generally provided with laboratories for the extraction of
radium emanation which is sealed up in small tubes for medical use.
These institutions own important quantities of radium, have a very good
equipment, and treat a great number of patients. I have visited some of
them, and this made me feel more deeply, if possible, the regret of not
having in France even one national institute capable of rendering the
same services. I hope that this lack will be filled in the near future.

The industry of radium has been started in France, but it is in America
that it has had its greatest development, owing to the presence of a
sufficient supply of the ore carnotite.[15] I was very much interested
in my visit to the most important of the factories, and I gladly
recognize the spirit of initiative in this undertaking. The factory owns
a collection of documentary films which enable one to appreciate the
effort made each day in collecting the ore scattered in the immense
fields of Colorado, in carrying and concentrating this ore originally
very poor in radium. On the other hand, the means of extraction of
radium are still the same which have been described in earlier chapters.

The greatest courtesy was paid me in my visit to the radium plant and
laboratory. I found the same reception at a factory of mesothorium which
presented me with some material, and where the officials expressed the
desire to help in my scientific work.

To make complete these travel impressions it would be necessary to speak
of the nature of the country. I recoil before the task, being incapable
of expressing in a few words the immensity and the variety of the spaces
which opened before my eyes. The general impression is one of unlimited
possibilities for the future. I keep a particularly vivid remembrance of
the great falls of Niagara, and of the magnificent colors of the Grand
Canyon.

On June 28th I embarked in New York on the same ship which had brought
me to the United States less than two months before. I would not take
the liberty, after so short a period of time, of giving an opinion on
America and the Americans. I would only say how deeply I have been
touched by the warm reception which was tendered everywhere to me and my
daughters. Our hosts wanted to make us feel that we were not with
strangers; and, on the other hand, many of them assured me that they
felt in entirely friendly surroundings when on the soil of France. I got
back to France with a feeling of gratitude for the precious gift of the
American women, and with a feeling of affection for their great country
tied with ours by a mutual sympathy which gives confidence in a peaceful
future for humanity.


[Footnote 15: Quite recently there has been started near Anverst an
important radium industry as a result of the discovery of uranium ore in
the Belgian Congo.]