untain
associated in the mind with the moon, it must not be imagined that upon
our satellite there are no mountains at all of the terrestrial type.
There are indeed many isolated peaks, but strangely enough they are
nearly always to be found in the centres of craters. Some of these peaks
are of great altitude, that in the centre of the crater Copernicus being
over 11,000 feet high. A few mountain ranges also exist; the best known
of which are styled, the Lunar Alps and Lunar Apennines (see Plate X.,
p. 200).

Since the _mass_ of the moon is only about one-eightieth that of the
earth, it will be understood that the force of gravity which she
exercises is much less. It is calculated that, at her surface, this is
only about one-sixth of what we experience. A man transported to the
moon would thus be able to jump _six times as high_ as he can here. A
building could therefore be six times as tall as upon our earth, without
causing any more strain upon its foundations. It should not, then, be
any subject for wonder, that the highest peaks in the Lunar Apennines
attain to such heights as 22,000 feet. Such a height, upon a
comparatively small body like the moon, for her _volume_ is only
one-fiftieth that of the earth, is relatively very much in excess of the
29,000 feet of Himalayan structure, Mount Everest, the boast of our
planet, 8000 miles across!

High as are the Lunar Apennines, the highest peaks on the moon are yet
not found among them. There is, for instance, on the extreme southern
edge of the lunar disc, a range known as the Leibnitz Mountains; several
peaks of which rise to a height of nearly 30,000 feet, one peak in
particular being said to attain to 36,000 feet (see Plate IX., p. 198).

[Illustration: PLATE X. ONE OF THE MOST INTERESTING REGIONS ON THE MOON

We have here (see "Map," Plate IX., p. 198) the mountain ranges of the
Apennines, the Caucasus and the Alps; also the craters Plato, Aristotle,
Eudoxus, Cassini, Aristillus, Autolycus, Archimedes and Linne. The
crater Linne is the very bright spot in the dark area at the upper left
hand side of the picture. From a photograph taken at the Paris
Observatory by M.M. Loewy and Puiseux.

(Page 200)]

But the reader will surely ask the question: "How is it possible to
determine the actual height of a lunar mountain, if one cannot go upon
the moon to measure it?" The answer is, that we can calculate its height
from noting the length of the shadow which it casts