416 Great Comet of 1843. 



eight hundred thousand. When we consider that the sun's surface is 

 four hundred and forty thousand miles from its centre, we find that both 

 comets approached much nearer the sun's surface than that surface to the 

 centre. t# 



"The period of the comet of 1680 is somewhat remarkable. Encke 

 found that one of fourteen thousand years would suit the observations 

 rather better than the supposition of its moving away in a parabola never 

 to return. This affords some ground for conjecture concerning the pe- 

 riod of the present comet. 



" Astronomers have dwelt with astonishment on the rapidity with 

 which the comet of 1680 whirled round the sun at the instant of its peri- 

 helion passage. This was such that if continued, it would have carried 

 it ten times round the sun in one day. The present comet would have 

 gone five times round the sun in the same time. In fact, it went half 

 round in four hours from two hours before to two hours after its perihelion 

 passage. The elements of the present comet require nice observations 

 for their determination. Though only twenty seven days past its perihe- 

 lion, this comet has 169° of anomaly in its parabolic orbit. This anom- 

 aly is far greater than that at which all comets except that of 1680, have 

 disappeared from view. Indeed, so unexpected is the circumstance of a 

 comet's being seen at this anomaly, that Burckhardt extended his table of 

 anomalies of comets, only to 164°, in consequence of which Prof. Ken- 

 dall and myself had to compute a new table for our own use for the occa- 

 sion. Some idea of this remarkable peculiarity may be formed by con- 

 sidering that a comet having an average perihelion distance, (the mean 

 distance of the earth for instance,) would be a whole century in arriving 

 at that point of its orbit to which the comet of 1843 has passed in less 

 than a month. This circumstance accounts for the bad success of the 

 first attempt to determine the elements from only approximate estimates 

 of the comet's place, — a method which with ordinary comets, usually 

 affords satisfactory information of the general character of the orbit." 



Of all the comets hitherto recorded, six only are known to have been 

 visible in the presence of the Sun — viz. those of 43 B. C, A. D. March 

 1402, June 1402, 1532, 1577, 1744. 



A letter from Prof. Loomis of Hudson, Ohio, dated March 27, states 

 that on account of clouds he had been able to secure only three observa- 

 tions on the nucleus, viz. on the 11th, 21st, and 25th. Before this last 

 observation, Prof. L. had made a computation of the elements founded 

 upon the first two observations, and an estimate of the position of the 

 nucleus as reported on the 28th of February. With the excellent instru- 

 ments of the Hudson observatory, Prof. L. has no doubt ere this secured 



a series of accurate observations; but on account of his distance from 

 us, we cannot expect to receive his elements in season for the present 

 number. m 



