Piatt, 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 instru- 

 ments. 

 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 instru- 

 ments. 



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. 



Gilmur, Bryan (end of 1 8th century), Philadelphia; also made clocks. 



Greenleaf, Stephen (fl. 1745), Boston. 



Greenough, Thomas (1710-1785), Boston; also made surveying, astronomical, 

 and nautical instruments. 



Greenwood, Isaac, Jr. (1730-1803), Boston. 



Hagger, Benjamin K. (c. 1769-1834), Boston and Baltimore; also made surveying 

 instruments. 



Halsy, James, II (1695-1767), Boston; also made surveying instruments. 



Halsy, John (fl. 1700), Boston. 



Ham, James (fl. 1754-1764), New York and Philadelphia. 



Ham, James, Jr. (fl. 1780), Philadelphia. 



Hamlin, William (1772-1869), Providence, R.I.; also made nautical and astro- 

 nomical instruments. 



Heisely, Frederick (1759-1839), Frederick, Md., and Lancaster, Harrisburg, and 

 Pittsburgh, Pa.; also made clocks and surveying instruments. 



Heisely, George (1789-1880), Harrisburg, Pa.; also made clocks. 



Hinton, William (fl. 1772), New York. 



Hooker & Fairman (before 1810), Newburyport, Mass. 



Jacks, James (fl. 1780's), Charleston, S.C.; also made surveying instruments. 



Jayne, John (late 18th century), Salem, Mass. 



King & Hagger (1759/60 to early 1760's), Newport, R.I.; also made nautical in- 

 struments. 



King, Benjamin (1707-1786), Newport, R.I.; also made nautical instruments. 



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