EXPECTED METEOR SHOWER. 121 



discovered a few months before the comet called Tempel's. 

 That a comet which is invisible to the naked eye should 

 have been discovered in the very year when first astronomers 

 made exact observations of the meteors which travel in its 

 track for it will presently be seen that the assumption 

 above mentioned was a just one cannot but be regarded 

 as a very singular coincidence. It was a most fortunate 

 coincidence for astronomers, since there can be but little 

 doubt that but for it Schiaparelli's theory would very soon 

 have been forgotten. As that theory was itself suggested 

 Dy the fortuitous recognition of another comet (only visible 

 at intervals of more than a century) at a time when attention 

 hid been specially directed to the August meteors, it may 

 fairly be said that the theory which now associates meteors 

 and comets in the most unmistakable manner was suggested 

 by one accident and confirmed by another. Albeit such 

 accidents happen only to the zealous student of nature's 

 secrets. We shall presently see that the fortunate detection 

 of Tempel's comet in 1866 was not the last of the series 

 of coincidences by which the theory of meteors was 

 established. 



Although the evidence favouring Schiaparelli's theory 

 was now strong, yet it was well that at this stage still more 

 convincing evidence was forthcoming. The date of the 

 November display has changed since the Leonides were 

 first recognised, in such sort as to show that the position of 

 their path has changed. The change is due to the disturb- 

 ing attractions of the planets. It occurred to our great 

 astronomer Adams, discoverer with Leverrier of distant 

 Neptune, to inquire whether the observed change accorded 

 with the calculated effects of planetary attraction, if the 

 Leonides are supposed to travel in any of the smaller paths 

 suggested by astronomers, or could be explained only by 

 the assumption that the meteors travel on the widely-extend- 

 ing path corresponding to the 33^-years period. The 

 problem was worthy of his powers in other words, it was a 

 problem of exceeding difficulty. By solving it, Adams 



