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be very faint, and it will require a powerful telescope to search 
for and discover it. 
There is yet another field in which this new telescope may 
reap great advantages for astronomy. It is suspected that more 
than one of the stars, those distant suns, may be attended by 
opaque dull planets. Mathematical analysis has already pointed 
to the existence of these attendants. It remains for the tele- 
scope to discover them. If the new Ealing reflector be 'really 
of the very highest excellence, it will be with that instrument we 
ought to look for these attending planets, these members of a 
foreign solar system. 
Lastly, there is the great field of photography. The new 
telescope takes instantaneous photographs of the moon two and 
a-half inches in diameter, photographs which can be enlarged 
with ease to good pictures of the moon a foot in diameter, pic- 
tures which will be valuable for astronomy, not mere interesting 
curiosities of science. It will, moreover, take photographs of 
Venus, Jupiter, Mars, and Saturn, showing much detail, and 
capable of being enlarged to half an inch in diameter. These 
planetary photographs will be of great use, as recording in 
unmistakable characters the true position and aspect of these 
planets and their satellites at different known epochs. 
The foregoing sketch will show that in constructing this 
new instrument Mr. Common has contributed in a most im- 
portant degree to the advancement of astronomy. 
