352 Observations on ■ 



and the breadth at half a degree ; it will be found, by 

 calculation, that the length in miles, was 40,000,000 ; 

 and the breadth 1,000,000 : the whole occupying a 

 fpace, which would not be filled by 60 million fuch 

 globes as our earth. 



Stars were frequently to be feen through the tail ; 

 though they were confiderably obfcured. That fide of 

 it, which was turned towards the part of the heavens, 

 to which the comet was moving, was a little convex, 

 as ufual, and brighter than the oppofite fide. I re- 

 peatedly obferved a dark line, like a fhadow, extend- 

 ing from one end of its tail, to the other ; and pafling 

 nearly through the middle, but a little further from the 

 advancing fide, than from the other. The whole ap- 

 pearance was fuch, as to correfpond very well with the 

 luppofition, that the tail was hollow. The light was 

 denfefl: on each fide, and gradually diminifhed, towards 

 the middle, where v/as a narrow fpace, almofl: as dark 

 as the neighbouring parts of the fky. This peculiarity 

 has not been mentioned, in the accounts of other comets, 

 except in a few inftances. Hevelius fl:ates, that one 

 which he faw in 1665, cafi: a fliadow through the mid- 

 dle of the tail. A fimilar appearance was obferved in the 

 comet of 1 744 ; and alfo by Cafiini, in that of 1 680. 



I have not entered into any fpeculations on the nature 

 and life, of this wonderful train of light, which is as un- 

 accountable, to the aflironomer, as to the vulgar obfer- 

 ver. Some extravagance of conception is certainly ex- 

 cufable, in attempting to explain the conftitution of a 

 luminous objedl, which occupies a greater fpace, than 

 all the other bodies in the folar fyfl:em. But the fchemes 

 which have hitherto been propofed, for this purpofe, are 

 rather to be confidered as difplays of the power of ima- 

 gination ; than fpecimens of the exercife of found and 

 fober reafon. Thofe who have a tafi:e for thefe vifiona- 

 ry hypothefes,may eafily contrive them for themfelves ; 

 or may find, in the common afl:ronomical works, a very 

 convenient aflbrtment of them, adapted to the fancy, of 

 almofl: every defcription of readers. 



Yale-College, March 2Ql/i, 1812. 



