in 1817 when the Government required his services as astronomer 

 to locate a portion of the United States-Canadian boundary in 

 accordance with the fifth article of the Treaty of Ghent. 



Ellicott was a member of a number of learned societies, including 

 the American Philosophical Society, the Society for the Promotion 

 of Useful Arts of Albany, and of the National Institute of France. 



Ellicott constructed a number of instruments for surveying and 

 astronomical observation, and he designed and used others that 

 were produced by his friend David Rittenhouse ^° (see figs. 10, 11). 

 Of particular interest in connection with Ellicott's career as a 

 clockmaker and instrument maker are two advertisements that 

 appeared in the Baltimore newspapers. The first one was in the 

 Maryland Journal and Baltimore Daily Advertiser on April 7, 1778: 



Ellicott's Upper Mills, April 4, 1778. Wanted, a person acquainted with the 

 Clock-Making business, and able to work by directions. Such a person will 

 meet with good encouragement by applying to Andrew Ellicott, sen. 



The second advertisement, in the same vein, appeared in the May 

 16, 1780, issue of the Maryland Journal: 



Good Encouragement will be given to either Clock or Mathematical instru- 

 ment makers, by the subscriber, living in Baltimore-Town. Andrew Ellicott. 



Owen Biddle 



Another mathematical practitioner associated with David Rit- 

 tenhouse in his observations of the transit of Venus was Owen 

 Biddle (1737-1799) of the North Ward, Philadelphia. 



In early life Biddle was an apothecary and a clock- and watch- 

 maker. In his shop "next door to Roberts warehouse" he sold 

 clock and watch parts and tools. From 1764 to 1770 he advertised 

 himself as "Clockmaker, and scientist, statesman and patriot." 

 As a Quaker, he participated actively in civic and patriotic affairs 

 of Philadelphia. During the American Revolution, in spite of his 

 religious affiliation, he fought for the defense of the Colonies and 

 was appointed Deputy Commissioner of Forage. Evidencing sin- 

 cere repentance, he was permitted to rejoin the Society of Friends. 



In 1769 Biddle took an active part in the preparations made by 

 the American Philosophical Society for the observation of the 

 transit of Venus. With Joel Baily he was sent to Cape Henlopen, 

 Delaware, with a large reflecting telescope borrowed from the Li- 



^° Catherine Van C. Mathews, Andrew Ellicott, His Life and Letters (New 

 York, 1908). 



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