216 



HISTOEY OF ASTRONOMY. 





PHILADELPHIA KQXTATOBIAL. 



circle, $1,200 ; clock, $300 ; comet seeker, $245 ; chro- 

 nometer, $250. 



The erection of this observatory formed an epoch in 

 the history of American astronomy, in consequence of 

 the introduction of a class of instruments superior to any 



