is the identical instrument used by John Dougherty, in laying 

 off Demint's first plat of Springfield, and by Jonathan Donnel 

 on the survey of 'New Boston.' " It is to be noted that some 

 discrepancies exist in the listing of names and dates of the previous 

 owners between Steele's History and those which actually appear 

 on the cover of the instrument. Steele apparently made the 

 changes he deemed necessary in his account of the instrument. 



Between 1791 and 1795 the same address was also occupied 

 by a cooper named Michael Davenport, and from 1797 to 1801 by 

 "the Widow Davenport," presumably widow of Michael. From 

 1802 to 1804 the same address is listed for William Davenport, 

 "Mathematical Instrument Maker," apprentice to William 

 Dean, and believed to be the son of Michael. During the next 

 ten years Davenport's address was 45 South Front Street, and 

 then, to 1820, was 25 South Front Street.^* Several brass sur- 

 veying compasses bearing his name have survived. 



Another maker of mathematical instruments about whom 

 nothing further is known is Charles Taws, who was listed in this 

 manner in the Philadelphia directory of 1795. 



The making of instruments in glass appears to have been a 

 specialized business in the Colonies, because those who worked in 

 this field do not appear to have produced instruments in other 

 materials. One of these makers of glass instruments — specifically 

 barometers, thermometers and "Glass Bubbles to prove spirits, 

 of different kinds"^ — was Alloysius Ketterer. He maintained a 



^ GiLLiNGHAM, op. cit. (footnotc 19), p. 302. 



%!5i,'C,. 



/ 



Figure 30. — Brass surveying compass marked "F. Heisely Fred:*town." In 

 collection of Ohio Historical Society, Ohio State Museum. 



61 



