Lambert, Johann Heinrich (1728–1777)

German physicist, mathematician, and astronomer. Largely self-taught, he travelled widely in Europe before settling in Berlin in 1765 under the patronage of Frederick the Great. He contributed to many branches of science, being the first to suggest that there may be galaxies beyond our own and the first to devise an accurate way of measuring the intensity of light. He also pioneered the sciences of pyrometry and hygrometry. The ‘lambert’, a unit of measurement of illumination equal to 104 lx, was named after him.

Lambert was born the son of a tailor at Mülhausen, Alsace (now Mulhouse, France). He worked as a clerk at an iron works from the age of 15 and then as secretary to the editor of the Basler Zeitung newspaper. During this time he educated himself, and was then for 10 years tutor to the children of a Swiss aristocrat, where he had access to an extensive library. His first major work, Photometria, was published in 1760. In mathematics he was the first to prove (in 1761) that the e and pi are irrational numbers. He also did some remarkable work on non-Euclidean geometry.