SAXTON, Joseph, mechanician, born in Huntingdon, Pennsylvania, 22 March, 1799; died in Washington, D. C., 26 October, 1873. He received a limited education, and was apprenticed to a watchmaker, after which he constructed a printing-press, and published a small newspaper at irregular intervals. In 1817 he went to Philadelphia, where he worked at his trade, and invented a machine for cutting the teeth of wheels, the outlines of which were true epicycloidal curves. Meanwhile he learned to draw with facility, and devoted some time to the study of engraving, lie then became associated with Isaiah Lukens, a celebrated machinist of Philadelphia, and constructed an astronomical clock with compensating pendulum and an escapement on a new plan devised by himself. The town clock in the belfry of Independence hall was also made by him about this time. In his ambition to obtain knowledge he became a member of the Franklin institute, and acquired reputation among its members for his ingenuity. In 1828 he visited England, and, being attracted to the Adelaide gallery of practical science in London, he constructed many ingenious mechanical toys for that institution. He also made numerous original investigations, met many celebrated engineers and mechanicians, and was introduced by Michael Faraday to the meetings of the Royal institution. In 1833 he exhibited before the British association for the advancement of science a magneto-electric machine, with which he showed a brilliant electric spark, decomposed water, exhibited the electric light between charcoal points, and gave a rapid series of intense shocks. During his residence in England he also invented the locomotive differential pulley, an apparatus for measuring the velocity of vessels, and a fountain-pen, and perfected the medal-ruling machine, an apparatus for tracing lines on metal or glass at a minute distance from each other that shall represent by an engraving the design on the face of the medal. He was tendered the office of director of the printing machinery of the Bank of England, but declined this place in order to accept, in 1837, that of constructor and curator of the standard weighing apparatus of the United States mint in Philadelphia. During his connection with the mint he constructed the large standard balances that are used in the annual inspection of the assays and the verification of standard weights. In 1843 he was given charge of the construction of the standard balances, weights, and measures to be presented to each of the states for insuring uniformity of measures in all parts of the country under the auspices of the United States coast survey. He invented an automatic instrument for recording the height of the tides, and applied the reflecting pyrometer that had been previously invented to the construction of measuring rods that would retain their length while subjected to different temperatures. A deep-sea thermometer and an immersed hydrometer were among his later inventions. Mr. Saxton received from the Franklin institute in 1834 a medal for his reflecting pyrometer, and in 1851 was awarded a gold medal at the World's fair in London for a large balance of extreme precision. In 1837 he was elected a member of the American philosophical society, mid in 1863 became a charter member of the National academy of sciences. A sketch of his life was contributed by Joseph Henry to the first volume of the "Biographical Memoirs" of the latter body (Washington, 1877).