122 ROUGH WAYS MADE SMOOTH. 



made that certain which Schiaparelli and his followers had 

 merely assumed. He showed beyond all possibility of 

 doubt or question that of all the paths by which the periodic 

 meteoric displays could be accounted for, the wide path 

 carrying the November meteors far beyond the track of 

 Uranus was the only one which accorded with the observed 

 effects of planetary perturbation. 



It was in the confidence resulting from this masterly 

 achievement that in 1872 some astronomers (among them 

 Professor Alex. Herschel, one of Sir J. Herschel's sons) an- 

 nounced the probable occurrence of a display of meteors 

 when the earth crossed the track of Biela's missing comet. 

 An occurrence of this sort was alone wanting to complete 

 the evidence for the meteoric theory. It had been found 

 that the August Perseids move as if they followed in the 

 track of a known comet ; the path of the November 

 Leonides had been shown to be identical with that of 

 another comet ; if astronomers could predict the appear- 

 ance of meteors at the time when the earth should pass 

 through the track of a known comet, even those who could 

 not appreciate the force of the mathematical evidence for 

 the new theory would be convinced by the meteoric display. 

 Possibly such observers would have been satisfied with a 

 meteor shower which would not have contented astronomers. 

 The display must have special characteristics to satisfy 

 scientific observers. The path of a body following Biela's 

 comet being known, and its exact rate of motion, the 

 direction in which it must enter our earth's atmosphere (if 

 at all) is determined. Calculation showed this direction to 

 be such that every meteor would appear to travel directly 

 from the constellation Andromeda, from a point near the 

 feet of the Chained Lady. A meteor might appear in any 

 part of the sky, but its course must be directed from that 

 point, otherwise it could not possibly be travelling in the 

 track of Biela's comet. 



The event corresponded exactly with the anticipations of 

 astronomers. On the evening of November 27, 1872, many 



