ADVERTISEMENT. 



Whoever attempts the enlargement of the bounds of knowledge 

 in any particular branch of science, in justice to himself, the 

 public, and previous laborers in the same field, should make him- 

 self familiar with all that has been previously published on the 

 subject. But information of this kind is so widely dispersed 

 through the journals and transactions of learned societies of all 

 parts of the civilized world, that index catalogues or references to 

 authorities are of the utmost importance to the investigator. In 

 consideration of this fact, the present work has been accepted for 

 publication, after having received the approval of our collaborators 

 in the line of astronomy. 



JOSEPH HENEY, 

 Secretary Smithsonian Institution. 



Washington, November, 1877. 



