Henry Letheby, British chemist, c 1860s.
© Science Museum / Science & Society Picture Library
Carte de visite photograph by the London Stereoscopic and Photographic Company of Letheby (1816-1876), analytical chemist and lecturer on chemistry at the London Hospital. He was also medical officer of health and analyst of foods for the city of London. His most important work was 'Food, its Varieties, Chemical Composition etc,' (1870).