Sharl Gilom Physicist Date of Birth: 15.02.1861 Country: Switzerland

Biography of Charles Edouard Guillaume

Charles Edouard Guillaume was a Swiss physicist born in Fleurier. He was the son of a clockmaker, Eduard Guillaume, who returned to Switzerland after leading a clock workshop in London for several years. Guillaume received his first lessons from his father and later attended school in Neuchâtel. At the age of seventeen, he entered the Federal Institute of Technology in Zurich, where he studied natural sciences, as well as German and French literature. His interest in science was further fueled by reading "Eloges academiques" by François Arago, the permanent secretary of the French Academy of Sciences. In 1882, Guillaume defended his dissertation on electrolytic capacitors and obtained his doctorate degree.

After a year of service as an artillery officer in the Swiss army, Guillaume became an assistant at the newly established International Bureau of Weights and Measures in Sèvres, near Paris. In 1902, he became the deputy director, and in 1905, he became the director of the Bureau, a position he held until his retirement in 1936, after which he was appointed honorary director. Guillaume's first work at the International Bureau was related to the accuracy of the mercury thermometer. He conducted calculations to account for changes in the volume of the thermometer due to temperature variations, as well as changes in the glass tube, and calibrated the thermometer accordingly. The results of his calculations were published in his treatise "Traite de thermometrie" in 1889.

While studying alloys, Guillaume discovered that steels with high nickel content had an unusually low coefficient of thermal expansion. This led to the development of a steel alloy containing 36% nickel, 0.4% manganese, 0.1% carbon, and 63.5% iron, which he named "Invar" because of its almost invariant nature when subjected to temperature changes. Guillaume also created methods for processing Invar while continuously monitoring its coefficient of thermal expansion. Invar meter bars became widely used as standards for measuring length. In his further research, Guillaume developed another alloy, called "Elinvar," containing 36% nickel, 12% chromium, and 52% iron, which had a much lower thermoelastic coefficient than iron. The use of Elinvar eliminated disturbances in steel tuning forks and balances in clocks caused by fluctuations in temperature.

In 1920, Guillaume was awarded the Nobel Prize in Physics for his discoveries concerning the anomalies in nickel-steel alloys and his contributions to precise measurements in physics. His work significantly influenced the understanding of the structure of matter in the solid state. Guillaume was a strong advocate for the international adoption of the metric system and used his exceptional tact and charm to promote its further dissemination.

Despite living in France for many years, Guillaume retained his Swiss citizenship. In 1888, he married A.M. Taufflib, and they had three children. Guillaume passed away on June 13, 1938, in Sèvres, France. He received honorary degrees from the universities of Geneva, Neuchâtel, and Paris. He served as the president of the French Physical Society and was a member of numerous scientific academies and societies. Guillaume was also awarded the Order of the Legion of Honor.