THE GKEAT COMET OF 1843. 129 



was, that it was turned almost directly toward the earth, 

 and we therefore saw it in the direction of its length. 



Has this comet ever been seen before ? In the year 

 1668 a comet appeared very similar to the present one. 

 Cassini saw the tail at Boulogne, March 10, and sub- 

 sequently an hour after sunset; but the head was 

 plunged in the rays of the sun. The tail was 45 in 

 length, and extended almost horizontally from west to 

 south. It was so brilliant that its image was distinctly 

 seen reflected from the sea; but this brightness lasted 

 only three days. The head was small and faint, and 

 difficult to be seen. Professor Henderson, of Edinburg, 

 computed the orbit of this comet, and obtained a result 

 very similar to the early results with the comet of 1843. 

 He then assumed the elements of the latter comet, and 

 from them computed the places in 1668. The results 

 accorded pretty well with the observations. Mr. Peter- 

 son has made the comparison with corrected elements, 

 and found the accordance still better. On the whole, 

 it appears that the comets of 168"8 and 1843 pursued 

 nearly the same path, and exhibited nearly the same ap- 

 pearances. 



A similar comet was seen in 1689. It was not seen in 

 Europe, but was observed at Pekin, and was most bril- 

 liant in the southern hemisphere, where the tail attained 

 the length of about 68. The head was bright, but the 

 tail was paler, and had the shape of a huge saber curved 

 at the extremity. The orbit of this comet was computed 



by Pingre, and its elements agree pretty well with those 



6* 



