10 REPORT—1863. 
at increasing angles, is a very beautiful sight. But it is chiefly to the variations in 
the central masses of lunar mountains and their physical bearings that the author 
wishes to direct attention. Many smaller mountains are simply like cups set in 
saucers, while others contain only one central or several dispersed cups. In Plato 
is a nearly central very small cup, bright, and giving a distinct shadow on the grey 
ground, as seen by Mr. Lockyer, Mr. Birt, and Professor Phillips himself. But in 
the centre of many of the larger mountains, as Copernicus, Gassendi, and Theophilus, 
is a large mass of broken rocky country, 5000 or 6000 feet high, with buttresses 
passing off into collateral ridges, or an undulated surface of low ridges and hollows. 
The most remarkable object of this kind which the author has yet observed with 
attention is in Theophilus, of which mountain two drawings are given, in which 
the author places equal confidence, except that the later drawing may have the ad- 
vantage of more experience, The central mass is seen under powers of 200 to 400 
(the best performance is from 200 to 300), and appears as a large conical mass of 
rocks about fifteen miles in diameter, and divided by deep chasms radiating from 
the centre. The rock-masses between these deep clefts are bright and shining, and 
the clefts widen towards the centre; the eastern side is more diversified than the 
western, and, like the southern side, has long excurrent buttresses. As the light 
grows on the mountain, point after point of the mass on the eastern side comes out 
of the shade, and the whole figure resembles an uplifted mass which broke with 
radiating cracks in the act of elevation. Excepting in steepness, this resembles the 
theoretical Mont d’Or of De Beaumont; and as there is no mark of cups or craters 
in this mass of broken ground, the author is disposed to regard its origin as really 
due to the displacement of a solidified part of the moon’s crust. He might be 
justified by Professor Seechi’s drawing of Copernicus in inquiring if the low ex- 
current buttresses may indicate issues of lava on the southern and western sides ? 
On the whole, the author is confirmed in the opinion he has elsewhere expressed, 
that on the moon’s face are features more strongly marked than on our own globe, 
which, rightly studied, may lead to a Imowledge of volcanic action under grander 
and simpler conditions than have prevailed on the earth during the period of 
subaérial voleanos. The author also exhibited a drawing of Aristarchus, showing 
some undescribed features in the aspect of that, the brightest part_of the moon’s 
surface. 
On the Changing Colour of the Star 95 Herculis, 
By Professor Prazzi Suytu, /.R.S., Astronomer Royal for Scotland. 
The star 95 Herculis is a double star, of which the two members are nearly of 
equal magnitude (about the 5th), and are six seconds apart, in R. A. 17h, 55m. 
33s,, and N. D. 21° 35' 56" epoch 1860, It has hitherto been catalogued as a 
diversely coloured pair of stars, one member being called “apple-green” and the 
other “cherry-red.” These colours have moreoyer been oka upon (as are the 
colours of all ordinary stars) as constant features, Being observed, however, by 
the author when he was on the Peak of Teneriffe, in 1856, they were found nearly 
colourless, and without any diversity of tint the one from the other. This obser- 
vation was considered anomalous at the time, and was so to a certain extent; but, 
on examining older authorities, the author has met with two other instances of an 
equality of pale colour being observed in the two components of 95 Herculis—one 
by Sestini in 1844-50, and the other by Struve in 1832°53; and remarks that, while 
these two epochs are separated by twelve years exactly to a tenth, the later of 
them precedes the Teneriffan observation in 1856-58 by almost exactly the same 
quantity. Now this looks like a regular periodic change, of yery short period; and 
it is not improbable that the twelve years constitutes a multiple of a shorter period 
still, during which the change of tint of the stars is so marked that, from being 
merely grey at a certain time, one star has been described as becoming an “ astonish- 
ingly yellow-green,” and the other “an egregious red.” Although this is the first 
instance of this kind yet detected in the sky, the author thinks that it will not be 
found a solitary one; and that its phenomena may bear some relation to the 
“eclipse ” pink prominences of our sun, and to auroral displays. 
