Chandlee & Bros. (fl. 1790-1791), Nottingham, Md.; also made surveying instruments. Chandlee, Ellis (1755-1816), Nottingham, Md.; also made surveying instruments. Chandlee, Goldsmith (1751-1821), Winchester, Va.; also made astronomical and surveying instruments. Chandlee, Isaac (1760-1813), Nottingham, Md.; also made surveying instruments. Crow, George (c.1726-1772), Philadelphia; also made surveying instruments. DeVacht, Joseph and Francois (fl. 1792), Gallipolis, Ohio; also made compasses and sundials. Doolittle, Enos (1751-1806), Hartford, Conn.; also made surveying and nautical instruments. Doolittle, Isaac (1721-1800), New Haven, Conn.; also made scientific instruments. Doolittle, Isaac Jr. (1759-1821), New Haven, Conn.; also made surveying instruments. Gilman, Benjamin C. (1763-1835), Exeter, N.H.; also made mathematical instruments. Gilmur, Bryan (fl. end of 18th century), Philadelphia; also made mathematical instruments. Harland, Thomas (1735-1807), Norwich, Conn.; also made surveying instruments. Heisely, Frederick A. (1759-1839), Frederick, Md.; also made mathematical and surveying instruments. Heisely, George (1789-1880), Harrisburg, Pa.; also made mathematical instruments. Hoff, George (1740-1816), Lancaster, Pa.; also made surveying instruments. Huntington, Gurdon (1763-1804), Windham, Conn., and Walpole, N.H.; also made surveying and other instruments. Kennard, John (1782-1861), Newmarket, N.H.; also made surveying instruments. Mendenhall, Thomas (fl. 1775), Lancaster, Pa.; also made mathematical instruments. Miller, Aaron (fl. 1748-1771), Elizabethtown, N.J.; also made compasses and surveying instruments. Platt, Benjamin (1757-1833), Danbury, Litchfield, and New Milford, Conn.; Lanesboro, Mass.; Columbus, Ohio; also made compasses and surveying instruments. Pope, Joseph (1750-1826), Boston; also made scientific instruments. Sibley & Marble (Clark Sibley and Simeon Marble) (late 18th century), New Haven, Conn.; also made mathematical instruments. Sower, Christopher (c. 1724-1740), Germantown and Philadelphia, Pa.; also made mathematical instruments. Voigt, Henry (1738-1814), Philadelphia; also made astronomical instruments. White, Peregrine (1747-1834), Woodstock, Conn.; also made surveying instruments. Witt, Christopher (practitioner) (fl. 1710-1765), Germantown, Pa.; also made mathematical instruments. MATHEMATICAL (GENERAL) Condy, Benjamin (fl. 1756-1792, d. 1798), Philadelphia. Dabney, John, Jr. (fl. 1739), Boston. Dakin, Jonathan (fl. 1745), Boston; also made balances. Davenport, William (fl. 1800-1820), Philadelphia; also made surveying instruments. Doolittle, Isaac (1721-1800), New Haven, Conn.; also made clocks. Emery, Samuel (late 18th century), Salem, Mass. Evans, George (fl. 1796, d. 1798), Philadelphia. Fairman, Gideon (1774-1827), Newburyport, Mass. Gilman, Benjamin C. (1763-1835), Exeter, N.H.; also made clocks.