210 Biela's Comet. 



At this appearance the comet approached very near the 

 earth's orbit; and it was calculated that, at the next, in 1832, 

 it would approach still nearer. This proximity was, however, 

 only to the orbit of the earth, which that of the comet inter- 

 sected in such a mauner, that when the comet itself crossed the 

 ecliptic, on the 22nd of October, the earth was at no less a 

 distance than forty-four millions of miles. But had the latter * 

 been then a month in advance of its actual place, it would have 

 passed through the comet — " a singular rencontre," writes Sir 

 John Herschel, in his Outlines, " perhaps not unattended with 

 danger." The general public, indeed, received the announce- 

 ment that the comet's orbit intersected the earth's, and that 

 therefore, a collision was at some time possible, with feelings 

 of considerable alarm. The celebrated Gibers showed that 

 such a collision, or rather a very close approach of the earth 

 and comet could, according to the laws of probability, take 

 place, at the most, only once in about 2,500 years. Much to 

 his chagrin, this expression was perverted, in many publica- 

 tions, into a very different one, that a collision between the 

 earth and comet would actually take place at the end of 2,500 

 years from that time. 



The first place at which the comet was seen in the year 

 1832, was at Rome, on the 25th of August, being detected 

 early in the morning in the constellation of Auriga. This was 

 by the use of the excellent ephemeris of Santini, who from 

 that time has kept the comet under his protection. At the 

 time of the discovery its light was feeble and nebulous, but by 

 the 28th of the same month, it had considerably improved. 

 The second observer was Sir John Herschel, at Slough, whose 

 remarks must be given in his own words : " On the night of 

 the 23rd, or morning of the 24th, of September, I observed 

 Biela's comet, and again next morning (24th-25th), as it was 

 then a bright object, and found without the least difficulty. I 

 pursued it no farther, which I now regret, as I have not since 

 heard of its. having been seen so early elsewhere, unless, as it 

 is said, at Rome, which, if verified, will be a great proof of the 

 advantage of an Italian sky. But from the extreme faintness 

 of it in the equatorial, on the 23rd and 24th of September, I 

 can hardly imagine with what instrument this observation can 

 have been made. I have since observed it on the 4th and 5th 

 instant"* {i.e., of October). By a " bright object," in the 

 first sentence, Sir J. Herschel evidently meant comparatively 

 to what he expected. Nicolai observed it at Mannheim, on 

 the 21st and 24th of October, and describes it as being a small 

 and excessively faint nebulous patch, only to be seen by great 

 straining of the eye. Bessel also, who observed it at Kbnigs- 

 * Ad. Nach., No. 236. 



