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Guillaume, Charles Edouard

alloys instruments physics iron–nickel

(1861–1938) Swiss physicist: introduced the use of iron–nickel alloys for the improvement of instruments.

Guillaume studied science at Zurich, securing a doctorate in physics. After a short time as an artillery officer, his career from 1883 was in the International Bureau of Weights and Measures, and as its Director from 1915. His work inevitably led him to study the thermal expansion of materials; and a chance observation caused him to focus on iron–nickel alloys: one with 36% Ni which he named ‘invar’ expands so little over a normal temperature range that it is widely used in clock pendulums and surveyors’ instruments. Another, ‘elinvar’, has a Young’s modulus which is constant over a range (ie its ‘springiness’ is constant) and this is used for the hairsprings of precision timepieces. Yet another, ‘platinite’ (40% Ni) expands at nearly the same rate as glass and can be sealed into it. For his services to metrology (precision measurement) Guillaume was awarded the Nobel Prize for physics in 1920.

Guillaume de Lorris and Jean de Meun [next] [back] Guggenheim, Daniel - Overview, Personal Life, Career Details, Social and Economic Impact, Chronology: Daniel Guggenheim

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