WILMARTH, Seth, inventor, born in Brattlebaro, Vermont, 8 September, 1810; died in Malden, Massachusetts, 5 November, 1886. He became a machinist in Pawtucket, Rhode Island, and in 1855 was appointed superintendent and master-mechanic of the Charlestown navy-yard. During the twenty years of his service there he made many valuable improvements in various departments, the most important being the large planer and the great lathe in the machine-shop, which were then the largest of their kind in the world, both bearing his name as inventor. Among his patents, numbering about twenty, were those for his revolving turrets, and for the hydraulic lift for raising the turret shafts on monitor vessels. Soon after the war the latter was submitted to the navy department, and was rejected as being of questionable utility, if not dangerous, its purpose having been efficiently accomplished by the means of a sledge-hammer and screw-wedge on many existing vessels. About 1873 the same plan was purchased by the United States government for $50.000.