}<3S CORRECTION OF 6vlC. 



NOTE. 



The distances of the moon have heen corrected from the 

 effects of refraction, parallax and the spheroidal figure of the 

 earth. In calculating the refractions, allowances have been 

 made for the state of the barometer and thermometer. — To de- 

 duce the longitude of the moon, use has been made of the lon- 

 gitudes of the stars lately determined by Maskelyne. 



No. LIV. 



Observations on the Comet of 1807 — 8. By William Dunbar. 



Read November 18th, 1808. 



THESE observations were made in latitude 31° 27' 48" N. 

 and 6 h 5' 50" nearly, west of Greenwich. The instrument 

 principally used for taking distances was a circle of reflection 

 by Troughton of London, graduated by the Vernier to ten se- 

 conds of a degree, and firmly supported upon a pedestal, adapt- 

 ed to every necessary movement; the observations were made 

 with the most scrupulous care, and as the pedestal afforded 

 every desirable facility, no observation was written down until 

 it had been re-examined several times by the separation and re- 

 union of the images. The clock was regulated to mean time. 



This comet was first seen here about the 20th of September 

 1807, and Seth Pease Esq. Surveyor of the Mississippi Territo- 

 ry, began to make observations on it the 22d of the same month; 

 and as I have the greatest reliance on the correctness of this 

 gentleman (who is an excellent astronomer) I shall here give 

 his observations which precede my own. 



Observations by Seth Pease Esq. 



h / h o i » 



•1807. Sep. 22. Tuesday at 7 12 16 Comet northerly from Saturn 7 21 IS 



7 34 17 ditto, below a Serpentis. 24 16 30 



23. 7 20 00 ditto, north of Saturn. . 7 46 7 

 7 28 00 ditto, below * Serpentis. 22 41 15 



24. 7 2 00 ditto, below a Serpentis. 21 12 50 

 7 13 00 ditto, north of Mars. . 19 33 30 



25. 6 45 00 ditto, below « Lyra. . 69 50 25 

 6 55 00 ditto, north of Mars. ■ 20 25 15 



