Charles Edouard Guillaume
Guillaume, Charles Edouard (1861-1938) was a Swiss physicist who made important contributions to the standardization of metric measurements. He won the 1920 Nobel Prize in physics for his work on nickel steel, which included discovering the alloy invar, an inexpensive material important to the precise operation of delicate instrumentation such as clockworks.
Guillaume earned his doctorate degree from the Swiss Federal Institute of Technology in 1882 and after military service as an artillery officer began working for the International Bureau of Weights and Measures, outside Paris in Sèvres. There, he was part of the effort to develop extremely precise standards of measurement that could be uniformly adopted throughout the scientific community. Some of his first work for the bureau involved research into thermometry. He helped set standard measurements for the kilogram and the meter and also developed a more precise measure of the volume of a liter.
In 1889, at the first Conference on Weights and Measures, Guillaume's research was included in the material presented to an international body of scientists. The Bureau's findings represented the first step in the true standardization of weights and measures and led directly to the establishment of the modern metric system.
Guillaume began his Nobel Prize-winning research into alloys, or mixtures of metals, in 1890. That research led to his discovery of an alloy of iron, nickel, and carbon he called invar, and also elinvar, a nickel, steel, and chromium alloy. The value of invar was that, even when subjected to temperature changes, its properties remained virtually invariable. Similarly, elinvar maintained its elasticity over a wide range of temperatures as well, making both substances highly valuable in clockmaking and the manufacture of other delicate instrumentation in which precision was crucial. These alloys allowed watches to be adjusted more accurately and contributed to chronometry, the science of accurately measuring time.