1866.] Astronomy. 253 
Collecting together the mean values of the difference of longitude 
for the four days, we have 
Difference of Longitude. 
m. 8. 
May 1 17 10°680 
2 10°648 
22 10°433 
25 10°463 
Combining these together with a due regard to the number of 
observations on each day, we obtain for the definitive value of the 
longitude of the Transit Circle of the Glasgow Observatory, 
17™ 10*-55 W. 
Similarly, for the time of the current’s passage, 
8. 
May A 0°023 
0:037 
22 0°035 
25 0°018 
Whence we obtain definitively 
Time of Current’s Passage = 0* * 029 
PROCEEDINGS OF THE RoyAL AsTRONOMICAL Society. 
M. Chacornac, in a letter dated 24th October, 1865, addressed 
to the President of the Royal Astronomical Society, refers to the 
continuation of his researches on the physical constitution of the 
Sun; and states that after various observations he has arrived 
definitively at the conclusion that the Sun is at least as luminous at 
its centre as in the brilliant envelope which bounds its visible 
contour. 
The Society also received from Mr. A. Brothers a sheet of photo- 
graphs of the Moon, taken during the Eclipse on the 4th October, 
1865, with his Equatorial telescope of five inches aperture. Mr. 
Brothers writes that the prints must not be looked upon as photo- 
graphs of the Moon, as many very much superior have been taken, 
but merely as pictures of the Kclipse. The atmosphere was so 
much disturbed during the whole time of the Eclipse that the 
sharpness of detail is lost to a great extent. He attempted to obtain 
the entire outline of the Moon, but failed to get more than greater 
sharpness of the shadow; this will be seen in No. 10, which was 
exposed fifteen seconds; Nos. 8 and 12 were exposed three seconds, 
and the remainder from one to about two-tenths of a second. 
At the December meeting of the Royal Astronomical Society, 
Professor Grant gave a verbal account of his successful experiments 
in distributing accurate time over the City of Glasgow. He stated 
that, in the time-signalling operations at Glasgow, Jones’s method 
