Henry D. Stone was born in 1815 and died at Windsor in 1898. He learned his trade as a millwright at Woodstock, Vt., but soon afterward came to Robbins & Lawrence. He remained with them and their successors for the rest of his career, more than thirty years. He has been very generally credited with the invention of the vertical turret as applied to the lathe, but the idea was by no means original with him. In 1845 a horizontal turret was designed and built by Stephen Fitch at Middlefield, Conn., to manufacture percussion locks for the United States Government. This machine is illustrated in the _American Machinist_ of May 24, 1900. It had a horizontal axis with eight positions for as many tools. In the same magazine for November 28, 1908, two turret lathes are illustrated and described, one with a vertical and the other with a horizontal turret, both of which were in use in the Gay & Silver shop at an early date, probably in the forties, at the time Howe was there as an apprentice. The horizontal turret principle was also in use by E. K. Root at the Colt Armory,[188] and J. D. Alvord is said to have used a turret screw machine in the Hartford plant in 1853. There is little doubt that both Howe and Lawrence had something to do with the development of the turret lathe at Windsor. The turret designs which Howe had built for him a few years later in Providence are all along the same lines. Stone unquestionably had a share in the development of the turret, for he made the drawing of the first Robbins & Lawrence turret machines and continued for many years the development of the turret lathe for the various companies which successively operated in Windsor. With the turret screw machine came the box-tool and hollow mill. _Machinery_ of May, 1912, illustrated and described a box-tool, fitted with two back rests and two cutting tools, which was made by Robbins & Lawrence at Windsor in 1850. [188] See Fig. 33. See also the valuable article by E. G. Parkhurst in the _American Machinist_, of May 24, 1900, p. 489, referred to above.