Yerkes, Charles Tyson (yûrˈkēz, –kəs) [key], 1837–1905, American financier, b. Philadelphia. He began his business career as a clerk in a Philadelphia grain commission house. He became a broker in 1858 and prospered, but in 1871 he was convicted of misappropriating city funds and was imprisoned. He regained his financial position through stock-market activities and became interested in the Philadelphia street railway system. He moved (1881) to Chicago, where by 1886 he had gained control of, and developed, the city transportation system. Later he went to London to participate in the development of the underground railway system of that city. In 1892, Yerkes furnished the Univ. of Chicago with the funds for the Yerkes Observatory, established (1897) at Williams Bay, Wis., near the Wisconsin-Illinois line.