Remarks on the Tails of Comets. 67 



established laws of nature, as if a mystical or spiritual nature 

 Avere unreservedly acknowledged to belong to them. In early 

 ages, it was in keeping with the prevailing superstition of the 

 times to speak of a comet, that " it came out of an opening in 

 the heavens, with blue feet like a dragon, and a head covered 

 with snakes ; in its length it was a bloody color, inclining to saf- 

 fron. From the top of its train appeared a bended arm, in the 

 hand whereof was a huge sword, in the instant posture of stri- 

 king. At the point of the sword was a star. From the star pro- 

 ceeded dusky rays, like a hairy tail ; on the side of them, other 

 rays like javelins or lesser swords, as if imbrued in blood ; be- 

 tween which appeared human faces of the color of blackish clouds, 

 with rough hair and beards." But who would believe that with- 

 in twelve years, a work has been published in England, the au- 

 thor of which traced so direct a connection between the motion 

 of the comet of 1811 and the military movements of Napoleon, 

 that he denounced all persons that denied to comets the character 

 of special messengers from Heaven, as insulters of Divine Wis- 

 dom.* 



The several causes which I have adduced in explanation of the 

 deviation of the tail from a direction exactly opposite to the sun. 

 will be deemed, I think, a sufficient illustration of the phenome- 

 non ; indeed, recent writers have scarcely alluded to the circum- 

 stance. " From the head," says the younger Herschel, '• and in 

 a direction opposite to that in which the sun is situated from the 

 comet, appear to diverge two streams of light," (fecf " The tails 

 of comets," says Olmsted, '-'extend in a direct line from the sun, 

 though they are usually more or less curved."J 



I think it will be conceded, that if the tails of comets consist 

 not of matter foreign to the medium in which they move, the the- 

 ory which I have advanced must be true ; at any rate, that the tails 

 of comets are but augmented solar light. Let us then institute an 

 inquiry relative to their materiality. The period has long gone 

 by since a doubt has existed in the minds of astronomers on the 

 subject of Universal Gravitation. Discovered by Newton, and 

 demonstrated by himself and Laplace, it is no longer an hypothe- 

 sis, or a mere theory ; it is truth, sublime and immutable, — not 



* Milne's Prize Essay, p. 181. t Treatise on Ast., p. 284, 



t Introduction to Astronomy, p. 233. 



