Young & Sons
 William James Young (1800–1870) probably born in Philadelphia was indentured as an apprentice to instrument maker Thomas Whitney of Philadelphia for seven years beginning in 1813. Young was first listed in the 1825 Philadelphia directory as a mathematical instrument maker. He continued in business by himself until 1867 when Thomas N. Watson and Charles S. Heller joined him and the firm became known as William J. Young & Co.