METEORIC ASTRONOMY. 109 



1772, 1805, etc. It travels in a long eccentric ellipse, and 

 completes its orbit in 2410 days about 6f years. It ap- 

 peared again, as predicted, in 1832 and 1846. 



Its orbit very nearly intersects that of the earth, and 

 thus affords a "remote possibility of that sort of collision 

 which has excited so much terror in the minds of many 

 people, but which an enthusiastic astronomer of the present 

 generation would anticipate with something like the sensa- 

 tional interest which stirs the soul of a London street-boy 

 when he is madly struggling to keep pace with a fire- 

 engine. 



The calculations for 1832 showed that this comet should 

 cross the earth's orbit a little before the time of the earth's 

 arrival at the same place; but as such a comet, traveling 

 in such an orbit, is liable to possible retardations, the cal- 

 culations could only be approximately accurate, and thus 

 the sensational astronomer was not altogether without hope. 

 This time, however, he was disappointed ; the comet was 

 punctual, and crossed the critical node about a month be- 

 fore the earth reached it. 



As though to compensate for this disappointment, the 

 comet at its next appearance exhibited some entirely new 

 phenomena. It split itself into two comets, in such a man- 

 ner that the performance was visible to the telescopic ob- 

 server. Both of these comets had nuclei and short tails, 

 and they alternately varied in brightness, sometimes one, 

 then the other, having the advantage. They traveled on 

 at a distance of about 156,000 miles from each other, with 

 parallel tails, and with a sort of friendly communication 

 in the form of a faint arc of light, wh'ich extended as a 

 kind of bridge, from one to the other. Besides this, the 

 one which was first the brighter, then the fainter, and 

 finally the brighter again, threw out two additional tails, 

 one of which extended lovingly towards its companion. 



The time of return in 1852 was of course anxiously ex- 

 pected by astronomers, and careful watch was kept for the 

 wanderers. They came again at the calculated time, still 

 separated as before. 



They were again due in 1859, in 1866, and, finally, at 

 about the end of last November, or the beginning of the 



