A. MATHEMATICS AND ASTRONOMY. 9 



PAPERS ON THE TRANSIT OF VENUS. 



Part II. of papers relating to the transit of Venus in 1874 

 has been published by the Navy Department, and is occu- 

 pied principally by a series of charts and tables prepared 

 by Mr. George W. Hill for facilitating the predictions of the 

 several phases of the transit. It is accompanied by four 

 charts representing the exterior and interior contact of both 

 ingress and egress, full directions being given for using them. 



THE ORIGIN OF METEORS AND COMETS. 



Proctor has recently advanced an idea as to the origin of 

 comets and meteors that may seem to be but the revival of 

 an old opinion, and one supposed to have been exploded. 

 The researches of Schiaparelli and ISTewton and others, in 

 that they showed the meteors to be regular members of the 

 solar system, seem to have temporarily satisfied the inquiry 

 as to the remote origin of these bodies. The former astron- 

 omer assumes them to exist generally throughout the inter- 

 stellar spaces, and to be successively drawn to one and then 

 to another sun, while Proctor reasons that these bodies are 

 now found to travel in groups or streams, that it is difficult 

 to conceive how our sun could draw a connected stream of 

 meteors to itself at any given epoch, and that if these bodies 

 were ejected from the self-luminous stars, we may with equal 

 plausibility suppose similar bodies to have been ejected from 

 the planets of our own system Avhen they were in a molten 

 condition. He accordingly shows the very moderate degree 

 of force required to eject a meteor from the surfiices of the 

 outer planets, and examines the orbits of such periodical 

 comets and meteors as are at present known. In accordance 

 with the suggestion of A. S. Herschel, he deduces the inter- 

 esting conclusion that the comets expelled from Jupiter would 

 mostly have a direct motion, or one in the same direction as 

 his own, w^hile those ejected from IsTeptune would be as likely 

 to have a retrograde as a direct motion. Proctor concludes 

 that many comets have sprung from Jupiter and Neptune, 

 and at least one from Uranus the latter beins: the well-known 

 November meteor stream, or the Leonides, which Hind has 

 shown to be connected with Tempel's comet. 5 A, January^ 

 1873. 



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