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.

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.

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 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.

In chemical terms, radium differs little from barium; the salts of these two elements are isomorphic, while those of radium are usually less soluble than the barium salts.

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.

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.

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.

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.

I was only 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.