140 THE CANADIAN NATURALIST. [Vol. vi. 



with the orbit of the great comet of 1862, as calculated by 

 Oppolzer ; and so discovered and demonstrated that a comet con- 

 sists of a group of meteoric stones. Prof. Newton, of Yale Col- 

 lege, United States, by examining ancient records, ascertained 

 that in periods of about thirty-three years, since the year 902, 

 there have been exceptionally brilliant displays of the November 

 meteors. It had lono- been believed that these interestins; visi- 

 tants came from a train of small detached planets circulating 

 round the Sun, all in nearly the same orbit, and constituting a 

 belt analogous to Saturn's ring ; and that the reason for the com- 

 paratively large number of meteors which we observe annually 

 about the 14th of November is, that at that time the earth's orbit 

 cuts through the supposed meteoric belt. Prof. Newton concluded 

 from his investigation that there is a denser j)art of the group of 

 meteors which extends over a portion of the orbit so great as to 

 occupy about one-tenth or one-fifteenth of the periodic time in 

 passing any particular point, and gave a choice of five difierent 

 periods for the revolution of this meteoric stream round the sun, 

 any one of which would satisfy his statistical result. He further 

 concluded that the line of nodes, that is to say, the line in which 

 the plane of the meteoric belt cuts the plane of the earth's orbit, 

 has a progressive sidereal motion of about 52"-4 per annum. 

 Here, then, was a sj)lendid problem for the physical astronomer ; 

 and, happily, one well qualified for the task took it up. Adams, 

 by the application of a beautiful method invented by G-auss, 

 found that of the five periods allowed by Newton, just one per- 

 mitted the motion of the line of nodes to be explained by the 

 disturbing influence of Jupiter, Saturn, and other planets. The 

 period chosen on these grounds is 33^ years. The investigation 

 showed further that the form of the orbit is a long ellipse, giving 

 for shortest distance from the sun 145 million kilometres, and for 

 longest distance 2^895 million kilometres. Adams also worked 

 out the longtitude of the perihelion and the inclination of the 

 orbit's plane to the plane of the elliptic. The orbit which he 

 thus found agreed so closely with that of Temple's Comet I. 

 1866, that he was able to identify the comet and the meteoric 

 belt.^^ The same conclusion had been pointed out a few weeks 



* Signer Schiaparelli, Director of the Observatory of Milan, wiio, 

 in a letter dated 3lst of December, 1866, pointed out that the elements 

 of the oi-bit of the August Meteors, calculated from the observed posi- 



