308 Observatio?is of the appearance of the Comet. 



able situation of the comet, and the course it has moved over 

 since its first appe.irance, are at once comprehended bv 

 persons abnost wholly unacqnaintctl wt'.h the mostsia)ple 

 and popular principles of" astronomical phajiiomena: a draw- 

 ing and description of this con)etarinm, with the method of 

 laving down the place (jf the comet upon its orbit, will be 

 the subject of a future conmumication. As the perihelion 

 distance of the comet is a little greater than the earth's 

 mean distance from the sun, its motion at its perihelion is 

 only about one and half time the earth's mean motion in 

 its orbit ; on which account, notwithstanding the earth 

 and comet are now moving in almost opposite directions, its 

 disappearance will be very gradual, and it may be expected 

 to adorn our hemisphere for six weeks or two months 

 longer before it vanishes to the eye unassisted by the tele- 

 scope. With the telescope it may probably be traced till 

 nearly the end of January, when it will asjain be so near the 

 sun as to be lost in his beams; and as its descent below the 

 plane of t!ie earth's orbit will take place ahout the beginning 

 of April, just after its conjunction with the sun, and being 

 at that time between three and four times the distance from 

 us that it is at present, it will he. too faint to be any longer 

 visible ; so that we may conclude that its disappearance to 

 the inhabitants of this earth will be about the middle of 

 January 1812. 



From the reduced geocentric latitudes it will appear that 

 the comet made its nearest approach to the earth between 

 the 17th and 23d of October. On the 25th, about half- 

 past six o'clock in the evening, the comet was so near to 

 the star marked ff 67 Herculis, that this star appeared to 

 the naked eye to be the nucleus of the comet : the phae- 

 nomenon must have been highly interesting to gentlemen 

 who happened to view it with a good telescope. To me it 

 appeared that the star had actu.dly suffered an occultation ; 

 hut beinsr in a situation where I had no telescojie at hand, 

 i was unable to make any further observations upon it. 

 Somer* Town, Oct. 26, 1811. 'fiiOMAS FiRMlNGER. 



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