Metrology

Danish astronomer who showed from the eclipses of Io that light travels at a finite speed, invented the transit instrument and meridian circle, and standardized Danish weights, measures and the calendar.

astronomy, optics, instrument making

German physicist who with Gauss founded absolute electromagnetic measurement and an early telegraph, proposed the first unified force law for moving charges, and with Kohlrausch measured the ratio of units that pointed to the speed of light.

electromagnetism, geomagnetism, metrology

Russian chemist who formulated the periodic law in 1869 and used it to predict gallium, scandium and germanium.

chemistry, periodic law, physical chemistry

American logician, scientist and philosopher who developed the logic of relations and quantifiers, existential graphs, the theory of signs and pragmatism, while measuring gravity for the U.S. Coast Survey.

logic, semiotics, philosophy of science

Experimental physicist who measured the speed of light with unprecedented accuracy, invented the interferometer used in the Michelson–Morley experiment, and became the first American Nobel laureate in science.

optics, experimental physics, metrology