1864.] Nasmyrn on the Physical Aspects of the Moon’s Surface. 899 
tho lunar materials on its surface is reduced in the latter proportion, 
while, on the other hand, by reason of the small magnitude of the 
Moon and its proportionately much larger surface in ratio to its magni- 
tude, the rate at which it parted with its original cosmical heat must 
have been vastly more rapid than in the case of the earth. Now, as the 
disruptive and eruptive action and energy are in proportion to the 
greater rato of cooling, those forces must have been much greater in the 
first instance ; and, operating as they did on matter so much reduced in 
weight as if must be on the surface of the Moon, we thus find in com- 
bination two conditions most favourable to the display of voleanic force 
in the highest degree of violence. Moreover, as the ejected material 
in its passage from the centre of discharge had not to encounter any 
atmospheric resistance, it was left to continue the primary impulse of 
the ejection in the most free and uninterrupted manner, and thus to 
deposit itself at distances from the volcanic vent so much greater 
than those of which we have any example in the earth, as to result in 
the formation of the craters of vast magnitude so frequently encoun- 
tered in a survey of the Moon’s surface. In like manner we find the 
ejected matter piled up to heights such as create the utmost astonish- 
ment; Lunar Mountains of 10,000 feet high are of frequent 
oceurrence, while there are several of much greater altitude, some 
reaching the vast height of 28,000 feet, and that almost at one bound, 
as they start up directly from the plane over which they are seen to 
cast their long black, steeple-like shadows for many a mile; whilst at 
other times they intercept the rays of the sun upon their highest 
peaks many hours before their bases emerge from the profound dark- 
ness of the long lunar night. 
Among the many terribly sublime scenes with which the Moon’s 
surface must abound, none can be grander than that which would 
present itself to the spectator, were he placed inside of one of these 
vast volcanic craters (Tycho, for instance), surrounded on every side 
by the most terrific evidences of volcanic force in its wildest features. 
In such a position he would have before him, starting up from the 
vast plane below, a mighty obelisk-shaped mountain of some 9,000 
feet in height, casting its intense black shadow over the plateau; and 
partly up its slope he would see an amphitheatrical range of moun- 
tains beyond, which, in spite of their being about forty miles distant, 
would appear almost in his immediate proximity (owing to the 
absence of that “aerial perspective,” which in terrestrial scenery 
imparts a softened aspect to the distant object), so near, indeed, as to 
reveal every cleft and chasm to the naked eye! This strange com- 
mingling of near and distant objects, the inevitable visual consequence 
of the absence of atmosphere or water, must impart to lunar scenery 
a terrible aspect; a stern wildness, which may aptly be termed un- 
earthly. And when we seek to picture to ourselves, in addition to the 
lineaments and conditions of the lunar landscape, the awful effect of 
an absolutely black firmament, in which every star, visible above the 
horizon, would shine with a steady brilliancy (all causes of scintil- 
lation or twinkling being absent, as these effects are due to the presence 
of variously heated strata, or currents in our atmosphere), or of the 
