18 



PROCEEDINGS OF THE AMERICAN ACADEMY 



and annular micrometers. The changes in the physical appearance of 

 this comet from night to night are particularly interesting. 



" June 25th. Observed with the spider-line and annular micrometers, 

 the comet being still sufficiently bright to bear illumination ; its tail is one 



or two degrees long. 



Olservalions on the Comets of February and Maij, 1846. 



