L, M. Rutherfurd on Astronomicait Photography. 307 
mat least every ten days, a labor not to be contemplated with 
uanimity. Dr. Draper has found the silver surface very much 
dumber of which might be kept at hand. : 
ving thus failed in astronomical photography with an or- 
y achromatic, with a correcting lens and with a reflector, I 
in the autumn of 1863, the construction of an objective, 
ussian government), is a mere compro- 
which both the visual and actinic quali- 
