They also undertake to reconnoitre the series of parallel ramparts discovered on the surface of the moon by Gruithuysen, a learned professor of Munich, who considered them to be a system of elevated fortifications raised by Selenite engineers.

These two still obscure points, and doubtless many others, can only be definitely settled by direct communication with the moon.
As to the intensity of her light there is nothing more to be learnt; it is 300,000 times weaker than that of the sun, and its heat has no appreciable action upon thermometers; as to the phenomenon known as the "ashy light," it is naturally explained by the effect of the sun's rays transmitted from the earth to the moon, and which seem to complete the lunar disc when it presents a crescent form during its first and last phases.
Such was the state of knowledge acquired respecting the earth's satellite which the Gun Club undertook to perfect under all its aspects, cosmographical, geographical, geological, political, and moral..