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 YEAR: Around 1915
 COMPANY: Ford Instrument Co., Inc.
Click here for further information on our rarity scale RARITY: Exceedingly Rare Information on the rarity of this item is unknown.

Time of Flight Clock


The history of mechanical analog computers is described from early developments to their peak in World War II and to their obsolescence in the 1950s. The chief importance of most of these computers was their contribution to the superb gunnery of the US Navy. The work of Hannibal Ford, William Newell, and the Ford Instrument Co. is the framework for analog computers of this time.

Hannibal Choate Ford was born in Dryden,N.Y., on May 8.1887. His parents were Abram Millard Ford (born February 22. 1831) and Susan Agusta Giles Ford (born June 3, 1834). As a young boy, Ford showed mechanical talent with clocks and watches. Between high school and college he worked at the Crandall Typewriter Company, Groton, N.Y., at the Daugherty Typewriter Company, Kittanning, and at the Westinghouse Electric Manufacturing Company. He studied mechanical engineering at Cornell University, graduating in 1903 as a “mechanical engineer in electrical engineering.” Evidently his classmates at Cornell respected his mechanical inventive ability, because his motto in their senior yearbook was, “I would construct a machine to do any old thing in any old way.” He was elected to membership in Sigma Xi, the honorary society for research. After graduation Ford worked for the J.G. White Company. New York (1903-1905) where he developed and held two basic patents issued in 1906 on the speed-control system long used in the New York subways. At the Smith-Premier Typewriter Company, Syracuse, N.Y. (1905-1909) he developed over 60 mechanisms of commercial importance and received a number of patents over the period 1908 to 1915.”

In 1909, Ford worked for Elmer A. Sperry. whom he had known as a young man in his home town. Ford assisted Sperry in the development of the gyrocompass, a mechanical device for determining own ship's heading. In 1915. Ford resigned from Sperry to organize his own company, the Ford Marine Appliance Corporation, which became the Ford Instrument Company in 1916. The company’s mission was to develop and sell fire-control systems to the US Navy. Its first product, Range Keeper Mark 1, was introduced into the US Navy in 1917 on the USS Texas. Ford’s Range Keeper Mark 1 performed a remarkable number of continuous functions in real time for a computing system in those days.

The "Time of Flight" clocks were used in the U.S. Navy in WWI. The clocks told the time when a shell fired "now" would reach the target. This would allow the soldiers to know when to load up the next shell for firing.

Clymer, Ben A. “The Mechanical Analog Computers of Hannibal Ford and William Newell.” IEEE Annals of the History of Computing, vol. 15, no. 2, 1993,

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