his apprentices may have been Christopher Sower (1693-1740), of 

 Germantown and Philadelphia, who achieved renown as a doctor, 

 farmer, author, printer, papermal^er, and clockmalver. He also 

 produced mathematical instruments." 



George Wall, Jr., of Bucks County, was the author of a pamphlet 

 on the subject of "a newly invented Surveying Instrument, called 

 the Trigonometer." The instrument was described and illustrated 

 in the pamphlet, which was published in Philadelphia in 1788. 

 Washington's own copy, bearing the inscription "To the President 

 of the United States from the x'\uthor" is in the collection of the 

 Boston Athenaeum. 



George Ford of Lancaster maintained a shop on West King 

 Street, probably from the end of the 18th century until 1840. 

 There he made tall case and other clocks, surveying compasses, 

 and other instruments for the retail trade. However, he ".did not 

 push the business of Watchmaking and Clockmaking so hard, for 

 the manufacture of nautical instruments and surveyors instru- 

 ments was a more important part of his business." "^ Upon his 

 death in 1842 he was succeeded by his son George Ford II. 



Thomas Mendenhall repaired clocks and mathematical instru- 

 ments in a shop on King and Queen Streets in the borough of 

 Lancaster in 1775.®'' 



John Wood of Philadelphia was a wholesale supplier of parts for 

 clockmakers and watchmakers. According to a notice in the May 

 7, 1790, issue of Pennsylvania Packet^ he had "pocket compasses, 

 steel magnets, Surveying compass needles, surveyors chains, etc." 

 Since no mention was made of making or mending instruments, it 

 is probable that Wood was merely importer and wholesaler. 



Another instrument maker of Philadelphia about whom little 

 is known is Bryan Gilmur, who worked at the close of the 18th 

 century making instruments and, possibly, clocks."" 



James Jacks (also listed as James Jack) first worked as clock- 

 maker and watchmaker in Charleston, South Carolina, in the 

 1780's; he later moved to Philadelphia where he maintained a shop 



^^ Carolyn Wood Stretch, "Early Colonial Clockmakers in Philadelphia," 

 Pennsylvania Magazine (July 1932), vol. 56, pp. 225, 235; Eckhardt, op. cit. 

 (footnote 9), pp. 18, 24, 198. 



®* D. F. Magee, "Grandfather's Clocks: Their Making and Their Makers in 

 Lancaster County," Papers read before the Lancaster (Pa.) Historical Society, 

 1917, pp. 63-77. 



^^ Prime, op. cit. (footnote 17), p. 260. 



™ Palmer, op. cit. (footnote 34), p. 200. 



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