and Equinoctial Sun Dials, Azimuth and Amplitude Compasses, Eliptical 

 and Triangular Compasses, and all sorts of Common Compasses . . . N.B. 

 He sets Load Stones on Silver or Brass, after the best manner.^" 



Jonathan Dakin worked as a mathematical balance-maker "at 

 the Sign of the Hand & Beam, opposite to Dr. Colman's Meeting 

 House" where he made a variety of scale beams in 1745.^^ 



An interesting advertisement by Rowland Houghton appeared 

 in the January 17-24, 1737, issue of the Boston Gazette. Houghton 

 announced that he had "lately improv'd on his new Theodolite, 

 by which the Art of Surveying is rendered more plain & easy than 

 heretofore." Houghton was active in the political scene in Boston, 

 as evidenced by the fact that in various issues of The Boston 

 Gazette for January and February 1739 he is listed variously as 

 "Commissioner," "Proprietors' Clerk" and as "Collector." 



Isaac Greenwood, Jr. (1730-1803), was born at Cambridge, 

 where he married Mary I'ams in 1757. He maintained a shop 

 where he combined the business of mathematical instrument 

 maker and ivory turner, and also imported hardware. After the 

 Revolution, he engaged in dentistry, specializing in making arti- 

 ficial teeth and in the manufacture of "umbrilloes." Paul Revere 

 apparently did printing for him on five different occasions between 

 1762 and 1774, and in about 1771 engraved his trade card, which 

 read: 



ISAAC GREENWOOD, Ivory Turner Next door to Doctor John Clark's 

 at the North End Boston. Turns all sorts of work in Ivory, Silver, Brass, 

 Iron, Horn, Wood, etc. Such as Billiard Balls, Tea Boards, Scallop'' and 

 Plain Salvers, Decanters . . . .^^ 



Isaac's father, Isaac Greenwood, Sr., was "Professor of Mathe- 

 maticks and Natural and Experimental Philosophy" at Harvard. 

 In the Boston Gazette for February 19-26, 1728, there appeared 

 the following notice of his installation : 



On the 13th of this Month at Ten in the Morning, The Honorable & Rev- 

 erend Overseers of the College at Cambridge, met the Corporation in the 

 College Hall, to Inaugurate Mr. Isaac Greenwood into the Office of Professor 

 of the Mathematicks, and Natural and Experimental Philosophy, lately 

 founded by that great and living Benefactor to this Society, Mr. Thomas 

 HoUis of London Merchant. The Rev. President being detain'd by illness, 



^^ Boston Gazette, June 18, 1745. 



3' Ibid., November 12, 1745. 



^^ Clarence S. Brigham, Paul Revere' s Engravings (Worcester, Mass.: American 

 Antiquarian Society, 1954), p. 118; Bernard W. Wienberger, Introduction to 

 the History of Dentistry (St. Louis, Mosby Co., 1948), 2 vols., vol. 2, pp. 119-134; 

 Isaac J. Greenwood, The Greenwood Family, 1934, pp. 68-78. 



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