No. 2.] BRITISH ASSOCIATION MEiETINO. 141 



earlier by Schiaparelli, from calculations by himself, on data sup- 

 plied by direct observations on the meteors, and independently by 

 Peters, from calculations by Leverrier on the same foundation. 

 It is, therefore, thoroughly established that Temple's Comet I. 

 1866, consists of an elliptic train of minute planets, of which a 

 few thousands or millions fall to the earth annually about the 14th 

 of November, when we cross their track. We have probably not 

 yet passed through the very nucleus or densest part ; but thirteen 

 times, in Octobers and Novembers, from October 13, a.d. 902, 

 to November 14, 1866, inclusive (this last time having been cor- 

 rectly predicted by Prof. Newton), we have passed through a part 

 of the belt greatly denser than the average. The densest part of 

 the train, when near enough to us, is visible as the head of the 

 comet. This astounding result, taken along with Huggins's spec- 

 troscopic observations on the light of the heads and tails of comets, 

 confirm most strikingly Tait's theory of comets, to which I have 

 already referred; according to which the comet, a group of me- 

 teoric stones, is self-luminous in its nucleus, on account of colli- 

 sions among its constituents, while its " tail" is merely a portion 

 of the less dense part of the train illuminated by sunlight, and 

 visible or invisible to us according to circumstances, not only of 



tion of their radiant point on the supposition of the orbit being a very 

 elongatedellipse, agreed very closely with those of the orbit of Comet 

 II. 1862, calculated by Dr. Oppolzer. In the same letter Schiaparelli 

 gives elements of the orbit of the November meteors, but these were 

 not sufficiently accurate to enable him to identify the orbit with that 

 of any known comet. On the 21st of January, 1867, M. Leverrier gave 

 more accurate elements of the orbit of the November meteors, and 

 in the Astronomische Nachrichten of January 9, Mr. C. F. W. Peters, of 

 Altona, pointed out that these elements closely agreed with those of 

 Temple's Comet (I. 1866), calculated by Dr. Oppolzer, and on Febru- 

 ary 2, Schiaparelli, having re-calculated the elements of the orbit of 

 the meteors, himself noticed the same agreement. Adams arrived 

 quite independently at the conclusion that the orbit of 33^ years 

 period is the one which must be chosen, out of the five indicated by 

 Prof. Newton. His calculations were sufficiently advanced before the 

 letters referred to appeared, to show that the other four orbits offered 

 by Newton were inadmissible. But the calculations to be gone through 

 to find the secular motion of the node in such an elongated orbit as 

 that of the meteors, were necessarily very long, so that th^y were not 

 completed till about March, 1867. They were communicated in that 

 month to the Cambridge Philosophical Society, and in the month fol- 

 lowing to the Astronomical Societv. 



