230 



HISTORY OP ASTRONOMY. 



wing has a gridiron pendulum, and was made by Charles 

 Frodsham. 





PBIME VEBTIOAL TEAN8IT. 



The refraction circle was made by Ertel and Son, from 

 plans and drawings furnished by Lieutenant Maury. The 

 telescope is eight and a half feet in length, with a clear 

 aperture of seven inches. It is supported in the middle 

 of the axis between two piers, and it has two circles of 



