Jean Louis Agassiz, American naturalist and glaciologist, c 1850-1873.

UNITED STATES - JUNE 10: Carte de visite photograph by Maull & Company of Jean Louis Agassiz (1807-1873). Swiss-born Agassiz studied at the medical school of Zurich, his interest being zoology. Agassiz was appointed Professor of Natural History at the University of Neuchatel in 1832. During this time he became interested in glaciers and discovered glaciers are mobile, tracing their history back to the ice ages. In 1846 after a successful tour of Boston, Agassiz was appointed Professor of Natural History at the Lawrence Scientific School at Harvard. He became an oceanographer in 1851 and in 1859 founded the Museum for Comparative Zoology at Harvard. Amongst his important publications are �Etudes sur les glaciers� (Glacier studies) and �System Glaciere� (the Glacial System). (Photo by SSPL/Getty Images)