Charles Edouard Guillaume was a distinguished Swiss physicist born in Fleurier on February 15, 1861, who dedicated his career to advancing precision measurement science. He received his early education in Neuchâtel before earning his doctorate from the prestigious Zurich Polytechnic. Following a brief military service in the artillery, Guillaume joined the International Bureau of Weights and Measures in Sèvres as an assistant in 1883, marking the beginning of his fifty-five year association with the institution. His exceptional contributions led to his appointment as Associate Director in 1902, Director in 1915, and eventually Honorary Director until his death in 1938.
Guillaume's most significant scientific achievement was the discovery of invar, a nickel-iron alloy with an exceptionally low coefficient of thermal expansion, which he identified in 1896 through systematic investigation of ferronickel alloys. This groundbreaking work was followed by his 1912 discovery of elinvar, an alloy with temperature-independent elasticity that proved ideal for precision timekeeping mechanisms. These materials revolutionized the fields of precision metrology, horology, and scientific instrumentation by enabling unprecedented accuracy in measurements unaffected by temperature fluctuations. The Nobel Committee recognized this transformative contribution to physics when awarding him the 1920 Nobel Prize in Physics for "the service he has rendered to precision measurements in physics by his discovery of anomalies in nickel steel alloys."
Beyond his famous alloy discoveries, Guillaume made substantial contributions to thermometry, the standardization of metric measurements, and even cosmology through his pioneering 1896 estimation of space temperature at 5-6 K. His work directly enabled advancements in precision timekeeping, astronomical instrumentation, geodetic surveying, and scientific measurement standards worldwide. Throughout his career, Guillaume received numerous honors including the John Scott Medal, honorary doctorates from the universities of Geneva, Neuchâtel and Paris, and recognition as an officer in the Legion of Honour. Today, his legacy endures through the continued use of invar and elinvar in precision instruments and his foundational contributions to the science of measurement that remain integral to modern metrology.
