furrows sunk between parallel ridges, bordering generally upon
the edges of the craters. Their length varied between ten and 100
miles, and their width was about 1,600 yards. Astronomers called
them chasms, but they could not get any further. Whether these
chasms were the dried-up beds of ancient rivers or not they were
unable thoroughly to ascertain.

The Americans, among others, hoped one day or other to
determine this geological question. They also undertook to
examine the true nature of that system of parallel ramparts
discovered on the moon's surface by Gruithuysen, a learned
professor of Munich, who considered them to be "a system of
fortifications thrown up by the Selenitic engineers." These two
points, yet obscure, as well as others, no doubt, could not be
definitely settled except by direct communication with the moon.

Regarding the degree of intensity of its light, there was
nothing more to learn on this point. It was known that it is
300,000 times weaker than that of the sun, and that its heat has
no appreciable effect upon the thermometer. As to the
phenomenon known as the "ashy light," it is explained naturally
by the effect of the transmission of the solar rays from the
earth to the moon, which give the appearance of completeness to
the lunar disc, while it presents itself under the crescent form
during its first and last phases.

Such was the state of knowledge acquired regarding the earth's
satellite, which the Gun Club undertook to perfect in all its
aspects, cosmographic, geological, political, and moral.