Astronomy. 231 
of brightness which his telescope permitted—and in determining 
fom 
their knowledge of a large portion of the southern sky. Since 
that time a permanent observatory has been established by the 
British Government at the same place, and a large number of 
supply this pressing need; and while at Santiago, he made the 
work was unfortunately suspended: but I have a received the 
gratifying assurance that the calculations are now to be com leted, 
and the resulting catalogue published by the Observatory at ash- 
ington * * * * * * * 
N or has the progress of the work failed to afford its due share 
of discoveries, It has given us the 
Ww 
rightness is not always the same, but undergoes systematic 
Variations, § be t e to considerable bril- 
lianey, and then fade away until telescopes of som re 
heeded for rendering them visible. Others still are now found to 
Which has been assigned to them by mére 
times past. Such stars must be carefully watched, fac 
‘ny regular and periodic fluctuation in the amount of their light 
either established or disproved. Of such cases there are already 
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