98 ON COMETS. 



only have witnessed. It also very often happens that a 

 comet, which before its disappearance in the sun's rays 

 was but a feeble and insignificant object, reappears mag- 

 nified and glorified, throwing out an immense tail and 

 exhibiting every symptom of violent excitement, as if set 

 on fire by a near approach to the source of light and heat. 

 Such was the case with the great comet of 1680 and 

 that of 1843, both of which, as I shall presently take 

 occasion to explain, really did approach extremely near 

 to the body of the sun, and must have undergone a very 

 violent heat. Other comets, furnished with beautiful and 

 conspicuous tails before their immersion in the sun's 

 rays, at their reappearance are seen stripped of that ap- 

 pendage, and altogether so very different that, but for a 

 knowledge of their courses, it would be quite impossible 

 to identify them as the same bodies. This was the case 

 with the beautiful comet of 1835-6, one of the most re- 

 markable comets in history. Some, on the other hand, 

 which have escaped notice altogether in their approach 

 to the sun burst upon us at once in the plenitude of their 

 splendour, quite unexpectedly, as did that of the year 

 1861. 



(7.) I come now to speak of the paths described by 

 comets in the sky among the stars (which I need hardly ob- 

 serve keep always the same relative situations one among 

 the other, and stand as landmarks, among which comets, 

 planets, the moon and the sun pursue, or seem to us to 

 pursue, their destined courses). Now we all know that the 

 sun, moon, and planets, keep to certain high roads, like 

 beaten tracks in the sky, from which they never deviate 



