278 The Great Comet q/'1861. 



interest among the members. His list will be printed at length, 

 with special localities, &c., for the various species, in the Annals 

 of the Botanical Society, part II.] 



ARTICLE XX.— 5T^e Great Comet 0/ 1861. 



{From advanced sheets of SillimavUs Journal^ Sept. 1861.) 



The suddenness of the apparition of the comet in northern 

 latitudes was one of the most impressive of its characteristics. 

 On the 2d of July after the twilight had disappeared, the head, 

 to the naked eye, was much brighter than a star of the first 

 magnitude, if only the effective impression be taken into account, 

 although as to intensity it was far inferior to a Lyrae, or even to 

 a Ursae Majoris. I should describe the head as nearly equal in 

 brightness to that of the great comet of 1858 between the 30th of 

 September and the 5th of October ; it should be considered, how- 

 ever, that the present comet was better situated, from its higher 

 position above the horizon at the end of twilight. 



The aspect of the tail suggested a resemblance to the comet of 

 March, 1843. It was a narrow, straight ray, projected to a dis- 

 tance of one hundred and six degrees (106*^) from the nucleus, 

 being easily distinguishable quite up to the borders of the milky 

 way. The boundaries for the most part were well defined and 

 easily traced among the stars. It was not until after two or three 

 hours of observation, that I could gain a clear comprehension of 

 the structure of the tail or tails as they presented themselves to 

 the naked eye and through a small opera-glass. It was then 

 evident that a diffuse, dim light with very uncertain outlines, 

 apparently composed of hazy filaments, swept off in a strong curve 

 towards the stars in the tail of Ursa Major — the southern edge 

 directed as low as towards Mizar. This was evidently a broad 

 curved tail, intersected on its curved side at the distance of a few 

 degrees from the nucleus by the long straight ray which at the 

 first glance, from its greatly superior brightness, seemed alone to 

 constitute the tail. The two were in fact counterparts of the 

 principal tail and the supplementary rays of the great comet of 

 1858, with this remarkable difference, that in the latter the 

 straight rays were so far inferior in brightness to the curved tail 

 as to have been recognized at only three observatories, those of 

 Poulkova, Gottingen, and Cambridge, U. S. — while with the 



