From Analytical Engine to Electronic Digital Computer: The Contributions of Ludgate, Torres, and Bush

This paper, based on an invited lecture given at MIT in March 1980, discusses the little-known work of Percy E. Ludgate (1883- 1922), Leonardo Torres y Quevedo (1852- 1936), and Vannevar Bush (1890- 1974). These three inventors, who apparently were unaware of one another's existence, were all directly influenced by know/edge of Charles Babbage's Analytical Engine, and each played a significant role in the history of the development of program-controlled computers.