Leslie John Comrie FRS (15 August 1893 – 11 December 1950) was an astronomer and a pioneer in mechanical computation. Life Leslie John Comrie was born in Pukekohe (south of Auckland), New Zealand, on 15 August 1893. He attended Auckland University College (part of the University of New Zealand) from 1912 to 1916, graduating with BA and MA degrees with Honours in Chemistry. During World War I, despite severe deafness, he saw action in France with the New Zealand Expeditionary Force, and lost his left leg in February 1918 to a British shell. While convalescing, he started using a mechanical calculator and went on to modify commercial calculators for specific projects. Having joined while in school in New Zealand, Comrie was eventually the first director (1920–1922) of the Computing Section of the British Astronomical Association. In 1923 he received a PhD from St John's College of the University of Cambridge. He travelled to the United States to teach at Swarthmore College and Northwestern University in 1924, where he also pioneered the teaching of numerical analysis. He returned to England to join the HM Nautical Almanac Office at the Royal Greenwich Observatory, where he became deputy superintendent in 1926. His article On the Construction of Tables by Interpolation was published in April 1928, and described the use of punched card equipment for interpolating tables of data, in contrast to the more inefficient and error-prone methods involving mechanical devices like the pinwheel calculators under the Brunsviga brand name. In the same year, he became the first person to use punched card equipment for scientific calculations, by using Fourier synthesis to compute the principal terms in the motion of the Moon between 1935 and 2000 (improving upon the predictions of Ernest William Brown). Wallace J. Eckert, an American student of Brown at Columbia University, would later use IBM's vast computational resources to refine the predictions even further. He was promoted to Superintendent of the Nautical Almanac Office in 1930. However, his unconventional use of machines for calculation caused tensions with his superiors, and he was suspended in August 1936. Comrie founded in 1937 the world's first private company for scientific computing, incorporated as Scientific Computing Service, Limited. During World War II, he headed a team of 30 scientists to computerize war work, such as the creation of bombing tables for the Allies of World War II. He later used this technology to computerize