SECTION VI. 



THE MANUFACTURE OP TELESCOPES IN THE UNITED 

 STATES. 



VARIOUS attempts have been made in this country to 

 manufacture both reflecting and refracting telescopes. I 

 shall speak of each of them in succession. 



REFLECTING- TELESCOPES. 



A great many reflecting telescopes have been con- 

 structed by amateur astronomers in different parts of the 

 country ; but, for the most part, these attempts have 

 been but moderately successful, and have contributed 

 but little, if any thing, to the progress of science. The 

 most important exception to this remark was in the case 

 of a telescope manufactured in 1838, by Messrs. Smith, 

 Mason and Bradley, the two former gentlemen being at 

 that time students of Yale College. This telescope had 

 an aperture of twelve inches, and a focal length of 

 fourteen feet. The mirror was cast, ground, and polished 

 by their own hands. Stars of less than one second's 

 distance, were separated by this instrument; the faint 

 star, " debilissima," near e Lyrae, was easily shown; 

 and the nebula in Hercules, between t] and , was re- 



