born May 10, 1826, Woodbourne, near Sheffield, Yorkshire, Eng.
died March 9, 1908, Sheffield
British amateur scientist.
Convinced of the value of the microscope to geology, Sorby began in 1849 to prepare thin sections of rocks, about 0.001 in. (0.025 mm) thick, for microscopic study. He developed a new type of spectrum microscope for analyzing the light of organic pigments (1865). His research on meteors led to studies of iron and steel, and his later studies included the origin of layered rocks, weathering, and marine biology. He published works dealing with the physical geography of geologic periods, rock breakdown and buildup, and the formation of river terraces. Sorby is considered the father of microscopical petrography and metallography.