THERMOMETRICAL OBSERVATIONS. 20^, 







No. XXI. 



AJlromm'ical^ and Thermometrical Ohfervations^ made on 

 the Boundary between the United Stales and His Catholic 

 Maje/Iy. By Andrew Ellicott. 



Philadelphia, Sept. 23d, 1800. 

 Dear Sir, 



IT is with real pleafure, that I embrace this op- 

 portunity of prefenting through you to the A- 

 merican Philofophical Society the following aflronomical 

 and mifcellaneous obfervations, made on the boundary 

 between the United States, and His Catholic Majefly. 



So far as this addrefs can be confidered as a mark of 

 refped:, you are entitled to it from the fervices you have 

 rendered this country, in the uniform attention, and the 

 judicious manner, in which you have difcharged the 

 laborious duties, of profeflor of the mathematicks in the 

 univerfity of Pennfylvania : But exclufive of this, you 

 are entitled to it from me in a more particular manner, 

 as the preceptor of my youth, and at all times fince, my 

 difinterefted friend. 



1 feel a conlidence that any errors, or inaccuracies, which 

 may be found in the following work, will not only meet 

 with your indulgence, but with that of every other perfon 

 of fcience, acquainted with the difficulties under v\'hich 

 I laboured. — To William Dunbar, Efq. of the Miffiffippi 

 Territory 1 feel myfelf under the greatefl obligations, 

 for his affiftance during the fliort time he was with us ; 

 his extenfive fcientific acquirements, added to a fingular 

 facility in making mathematical calculations, would have 

 reduced my labour, to a mere amufement, if he had 

 continued. — To my affiftants Meffrs. Gillefpie, Ellicott, 

 junr. and Walker, the former of whom aded as fur- 



veyor. 



