ON COMETS. 133 



distance from the head being then only about 13,000,000 

 miles, and more than one observer having noticed and 

 been much struck with an unusual and general brightness, 

 like an auroral light not confined to the neighbourhood 

 of the comet, but spreading over the whole sky. The 

 most remarkable peculiarity of this comet, however, con- 

 sisted in the enormous length which one side of its tail 

 attained between the 2d and the 4th of July, extending 

 in a perfectly straight but feeble ray from near the star 

 Alpha in the Great Bear, to and beyond that designated 

 by the same letter in Ophiuchus, or over 75 degrees in 

 angular measure, contrasting strikingly with the stunted 

 development and bushy aspect of the opposite branch. 

 Its head, when viewed with good telescopes, exhibited 

 the same general phenomena of luminous jets and 

 crescent-like emanations as its predecessor, but much 

 less complex and varied. Owing to the great inclination 

 of its orbit, this comet, coming to us from the southern 

 side of the ecliptic, soared high above it on the northern 

 side and remained long and conspicuously visible as a 

 cricunipolar object, the whole of its diurnal course being 

 above our horizon. Not so its successor of 1862, whose 

 orbit being but slightly inclined to our own, its motion 

 retrograde (or meeting the earth), its perihelion distance 

 almost exactly equal to our distance from the sun, and 

 its passage through the perihelion occurring at a time 

 when the earth was not very remote from that point, it 

 passed us closely and swiftly, swelling into importancCj 

 and dying away with unusual rapidity. The ph?enomena 

 exhibited by its nucleus and head were on this account 



