48 ASTRONOMICAL OBSERVATIONS. 



My aflbciates in tracing the north boundary of Pennfylvania 

 were Dr. Rittenhoufe, James Clinton, and Simeon De Wit, 

 in the year 1786. The fii-fi: of thofe gentlemen left us in the 

 beginning of September. — The year following my aflbciates 

 were Andrew Porter, Abraham Hardenberg, and AVilliam 

 Morris. 



I have omitted the calculations, and given only the refults, 

 for the following reafons, jirjl they would have fwelled this 

 paper to a great X^-agXkv, fecondly no difficulty can arife in making 

 them, to any perfon moderately acquainted with practical ailro- 

 nomy, except in thofe fmall equations depending upon the ef- 

 fefts of aberration and nutation, which from the prefent Im- 

 proved fi:ate of this fcience, have become abfolutely neceflary ; 

 and thirdly becaufe I intend concluding this paper, with a 

 iliort elfay defigned to render eafy fo much of the calculations, 

 as depend upon the effefts of aberration and nutation. 



The following emerfions of the ill Satellite of Jupiter were 

 abferved in Baltimore, in the State of Maryland. The tele- 

 fcope which I ufed was acromatic, and magnified about 60 

 times. 



January 1788, 2^ 8'' 6' 33" hazy atmofphere") 



9 IB OH veryclenr (.Mean Time. 



18 6 23 57 do. I 



25 8 18 54 do. J 



Obfervations made at Georgetown, in the diftrift of Co- 

 lumbia on the annular ecHpfe of the Sun in the year 1791. 



The beginning of the eclipfe could not be obferved, the fun 

 being below the horizon. 



fi8''39' I '.25 annnlas completed T 

 April 2d ■{ 18 43 15 .25 annulas broken > Mean Time. 



L'9 55 37 -75 end of the eclipfe J 

 From an uncommon undulation in the atmofphere till towards 

 the end of the eclipfe, I cannot pretend to be certain within 

 two or three feconds of the completion, and breaking of the an- 

 nulas ; but the end may be relied on as correft. The lat. of 

 Georgetown is about 38° 55' N. 



In the city of Wafliington lat. 38° 52' 40" N. I obferved the 

 following occultation of Aldebaran by the Moon. 



Immerfionl T f 21'' T*" 55' 49"'5l A.,r,n..»,.f 'r;,^,. 



Emerflon j J^"""^ '793 j^, ^ \\ 7i .J j Apparent Time. 



A number 



