THE GREAT COMET OF 1843. 



really brighter than the head, only more conspicuous 

 from its greater size. A large object, though faint, is 

 much more noticeable than a small one of intenser light. 

 Thus the milky-way is little more than an assemblage 

 of faint stars, no one of which singly would make any 

 distinct impression upon the naked eye. 



The nearest approach of the comet's head to the earth 

 was about 80 millions of miles, being very soon after the 

 perihelion passage. The absolute diameter of the neb- 

 ulosity surrounding the head was about 36,000 miles. 

 The apparent length of the tail has already been stated ; 

 but the absolute dimensions were still more extraordinary. 

 .The following table was computed from the best ob- 

 servations, and shows the progress of the formation of 

 the tail after perihelion. The comet passed its perihelion 

 on the afternoon of February the 27th, Greenwich 

 time. 



Length of tall. 

 Miles. 



February 28, 35,000,000 



March 



55,000,000 

 70,000,000 



3, 82,000,000 



91,000,000 

 96,000,000 



6, 99,000,000 



7, 100,000,000 



8, 101,000,000 



9, 102,000,000 

 11, 103,000,000 

 13, 104,000,000 



March 



u 

 u 

 a 

 u 

 u 

 II 

 u 

 . It 



April 



Length of taiL 

 Miles. 



15, 105,000,000 



17, 106,000,000 



18, 106,000,000 



19, 107,000,000 



20, 107,000,000 



21, 108,000,000 

 24, 108,000,000 

 26 3 106,000,000 

 27, 105,000,000 



30, 101,000,000 



31, 98,000,000 

 1, 95,000,000 



The visible portion of the tail attained its greatest 

 length early in March, remained nearly stationary for 

 some time, and during the first week of April suddenly 



