122 ON COMETS. 



i^th, avers that he had a good viezv of it on the i^th, 

 and remarked nothing particular in its appearance. Be 

 that as it may, the comet from a single became a double 

 one. What domestic troubles caused the secession it is 

 impossible to conjecture, but the two receded farther 

 and farther from each other up to a certain moderate 

 distance, with some degree of mutual communication and 

 a very odd interchange of light one day one head being 

 brighter and another the other till they seem to have 

 agreed finally to part company. The oddest part of the 

 story, however, is yet to come. The year 1852 brought 

 round' the time for their reappearance, and behold! there 

 they both were, at about the same distance from each 

 other, and both visible in one telescope. 



(37.) The orbit of this comet very nearly indeed inter- 

 sects that of the earth on the place v/hich the earth oc- 

 cupies on the 30th of November. If ever the earth is to 

 be swallowed up by a comet, or to swallow up one, it will 

 be on or about that day of the year. In the year 1832 

 we missed it by a month. The head of the comet en- 

 veloped that point of our orbit, but this happened on the 

 29th of October, so that we escaped that time. Had a 

 meeting taken place, from what we know of comets, it is 

 most probable that no harm would have happened, and 

 that nobody would have known anything about it.* 



* It would appear that we are happily relieved from the dread of 

 such a collision. It is now (Feb. 1866) over due! Its orbit has 

 been recomputed and an ephemeris calculated. Astronomers have 

 been eagerly looking out for its reappearance for the last two 

 months, when, according to all former experience, it ought to have 



