Hanks, Truman (fl. 1808), Mansfield and Litchfield, Conn.
Harland, Thomas (1735-1807), Norwich, Conn.; also made clocks.
Heisely, Frederick A. (1759-1839), Frederick, Md., and Lancaster, Harrisburg, and Pittsburgh, Pa.; also made clocks and mathematical instruments.
Heisely, George (1789-1880), Harrisburg, Pa.; also made clocks and mathematical instruments.
Holcomb, Amasa (1785-1875), Southwick, Mass.; also made astronomical instruments.
Houghton, Rowland (c. 1678-1744), Boston.
Huntington, Gurdon (1763-1804), Windham, Conn., and Walpole, N.H.; also made clocks and other scientific instruments.
Jacks, James (fl. 1780's), Charleston, S.C.; also made mathematical instruments.
Kennard, John (1782-1861), Newmarket, N.H.; also made clocks.
Lamb, A., & Son (1780's), New York; also made mathematical and nautical instruments.