3QO THE BORDERLAND OF SCIENCE. 



time obtained as to the apparent track of these meteors. 

 It is necessary to mention that such information was 

 essential to success in the main inquiry. Now it had 

 chanced that in 1862 a fine comet had been seen, 

 whose path approached the earth's path very closely 

 indeed. This led the Italian astronomer Schiaparelli 

 to inquire whether there might not be some connection 

 between this comet and the August shooting-stars, 

 which cross the earth's path at the same place. He 

 was able, by comparing the path of the comet and the 

 apparent paths of the meteors, to render this opinion 

 highly probable. Then came inquiries into the real 

 paths of the November meteors, these inquiries being 

 rendered just practicable by several coincidences, as 

 (1) the exact observations just mentioned; (2) the 

 existence of certain old accounts of the meteor shower ; 

 (3) the wonderful mastery obtained by Professor 

 Adams over all problems of perturbation (for the 

 whole question depended on the way in which the 

 November meteors had been perturbed) : and (4) the 

 existence of a half-forgotten treatise by Gauss, sup- 

 plying formulae which reduced Adams' labour by one- 

 half. The path having been determined (by Adams 

 alone, I take this opportunity of insisting),* the 

 whole question rested on the recognition of a comet 

 travelling in the same path. If such a comet were 



* Leverrier, Schiaparelli, and others calculated the path on the as- 

 sumption that the occurrence of displays three times per century im- 

 plies a periodic circulation around the sun in about thirty-three years 

 and a quarter ; but Adams alone proved that this period, and no other, 

 must be that of the November meteors. 



