Mr. Thomas Fowler

An English inventor whose most notable invention was the thermosiphon which forms the basis of most modern central heating systems. Much of the knowledge available about him comes from his son, the Reverend Hugh Fowler, who produced a biography of his father. In 1840 he produced a mechanical calculating machine which operated using ternary arithmetic. Apprehensive in case his ideas should again be stolen as it was with the thermosiphon, he designed and built the machine single-handed from wood in the workshop attached to his printing business. To compensate for the limited precision achievable using wooden components, he constructed the machine on a large scale; it was 6 feet long by 3 feet deep and 1 foot high (1800 x 900 x 300 mm). He had previously developed methods using balanced ternary arithmetic to simplify the complex monetary calculations he was obliged to perform on behalf of the Torrington Poor Law Union in his capacity as its treasurer, which he later published in his book Tables for Facilitating Arithmetical Calculations. His machine was designed to give mechanical form to these techniques, the choice of balanced ternary allowing the mechanisms to be simple, though the values had to be converted to balanced ternary before processing and the results converted back to decimal at the end of the calculation. Though the machine did not survive to the present day, a replica has been constructed from a two-page description of it made in 1840 by the prominent mathematician Augustus DeMorgan. This replica resides at the Science Museum in London.