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.
[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.
[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.