196 THE BORDERLAND OF SCIENCE. 



passage would be November 28 ; and comparing this 

 with the fact that in 1830 the date was November 30, 

 we see that the date for the present year would be 

 November 27.* 



Next, as to the direction in which Bielan meteors 

 would salute the earth. The comet travels in the 

 same direction round the sun as the earth, and, 

 moving more swiftly than the earth when in her 

 neighbourhood, can manifestly only reach her from 

 behind. The comet also crosses her track from the 

 outside, travelling on a path slightly inclined down- 

 wards, or from the north. All this agrees with what 

 was stated above, as to the course of the meteors seen 

 last November. But the agreement is very close indeed 

 when details are considered. We can tell the very 

 part of the heavens whence the comet would seem to 

 come if at any time it actually overtook the earth ; 

 and this part of the heavens (making the calcu- 

 lation for the year 1872) would be close to the feet of 

 Andromeda. Now, the best accounts of the recent 

 meteoric display describe the shower as having its 

 c radiant point ' in that very region of the heavens. By 

 the best accounts, I do not, of course, mean those 

 which agree best with the theory that the meteors 



* It would not ;be desirable -to enter here into the recondite considera- 

 tions affecting the estimated position of the comet's path. What is 

 said above suffices to show, in a general way, that November 27 is 

 about the right date at present ; but the .real shifting .of the date takes 

 place in a very complicated fashion, the mere description of which would 

 be quite unsuited for these pages, while the explanation could only be 

 understood by the mathematician. 



