340 
PROFESSOR PHILLIPS ON SOME PARTS 
like a system of radiating fissures, and Mr. Nasmyth very ingeniously imitated their 
direction at least by a glass globe filled with water, which was made to crack in a nearly 
regular manner from a centre. But their great and unequal width, their entire want 
of relief, and the peculiarity of their reflexion of light, seem to point to some other 
cause. The reflexion seems to be of the kind called “ metallic perhaps metals or metal- 
loids may there be covered by a translucent crust, which may reflect light of low 
incidence, but transmit light of higher incidence, to be reflected from the surface below. 
This is the nearest conjecture which has occurred to me. 
The parts of the moon’s surface to which I have devoted most time are the ring- 
mountains of Gassendi and Theophilus. The sketches here given of Cyrillus and 
Catharina (Plate XVI.), are only first though not careless drawings, in which are 
omissions, which I hope at some future time to supply. Bather more progress has 
been made with Posidonius, Aristarchus, and Herodotus. I have also begun to sketch 
the large and noble group which lies to the south of Ptolemseus, and it is my earnest 
hope to be able to finish these drawings as well as to complete a good deal of work on 
the Bills. 
In any further attempts of my own to contribute facts toward the survey of the moon, 
now again taken in hand by the British Association, I shall probably select for careful 
work some particular features, such as the mountains in the midst of a large crater, the 
bosses and cup-like hills on the outward slopes of such a crater, the rents in mountain- 
ridges, and the low winding banks which appear on the broad grey tracts. But for 
those who desire to perform a work of high value, and lay a sure foundation for accu- 
rate surveys of particular mountains, I would earnestly recommend a strict reexamina- 
tion of every element in the great picture of Copernicus, for which we are indebted to 
the Boman Astronomer. 
The descriptions which follow relate principally to Gassendi and Theophilus. 
Gassendi (Plate XV.), whose centre is situate nearly in Lat. S. 16° 56' and in Long. 
E. 39° 82', has the long diameter of its apparently elliptical boundary inclined to 
the equator about 64° 30'. Measured in this direction, the ring has a diameter of 
forty-eight miles ; the shorter diameter is about thirty-six. Sunrise happens when the 
moon is 10 - 5 days old, midday at about eighteen, and sunset at twenty-five days. In 
consequence of its position on the moon’s disk, shadows usually fall from elevated objects 
a little toward the south. 
At the instant of sunrise on the central peaks, the whole of the exterior ring is en- 
lightened, except for a few miles on the south border, where the crests are low and 
divided (18th May, 1853, 10 p.m.). As the early morning advances, very broad shadows 
from the western border spread over the interior, and bring out in every part a mingled 
effect of unequal height and unequal reflective power of the surface. When the moon 
is eleven or twelve days old, the interior appears everywhere diversified by lights and 
shades, nowhere smooth, but marked by ridges and hollows in various directions. Within 
