188 Mr. G. J. Stoney on the Connexion 



by the material exhalations from the rose for the mind to become 

 conscious of the sweetness of the flower; and a musk-rat's -tail 

 must part with a portion of its substance as long as it continues 

 to convey an odorous impression through the nose to the brain. 

 The conclusion we draw from these facts is, as stated above, 

 that the gross molecules of substances associated with aether 

 transmitting radiant heat do not acquire an modulatory motion 

 (which could be apprehended by the senses from a distance), but 

 an orbital one. This orbit is such that it can pass through three 

 several forms, Which are distinct though cognate; and such are 

 the conic sections — the ellipse, parabola, and hyperbola. 



XXIV. On the Connexion between Comets and Meteor. 

 By G. Johnstone Stoney, M.A., F.R.S.* 



THE astonishing fact which Signor Schiaparelli brought to 

 light some months ago, that there are comets moving in 

 the tracks of the August and November meteors, compels us to 

 infer that there is some intimate physical connexion between the 

 two. In January last M, Leverrier pointed out that such a stream 

 of meteors must have been in compact clusters when they under- 

 went the great perturbations which brought them into perma- 

 nent connexion with the solar system. And Mr. Graham has 

 lately shown that the meteoric iron which reaches our earth had 

 been at some previous time red-hot, and that when last red-hot 

 it was acted on by hydrogen under considerable pressure — a 

 pressure of perhaps six or more atmospheres. It is my present 

 design to make use of these inferences as data, and to endeavour 

 to trace by their help what the physical connexion between the 

 comets and the meteors has been. 



If interstellar space, external to the solar system, be, as is 

 most probable, peopled with innumerable meteoric bodies inde- 

 pendent of one another, a comet while outside the solar system 

 would in the lapse of ages collect a vast cluster of such meteor- 

 ites within itself. Each meteorite which approached the comet 

 would in general do so in a parabolic orbit ; and if it came near 

 enough to pass through a part of the comet, this parabolic orbit 

 would, by the resistance of the matter of the comet, be converted 

 into an ellipse. The meteor would therefore return again and 

 again, and on each occasion that it passed through the comet its 

 orbit would be still further shortened, until at length it would 

 fall in, and add one to whatever cluster had been brought to- 



* From the Monthly Notices of the Royal Astronomical Society for 

 June 14, 1867. 



