are diversities of shade, which allure us to form conjectures about their significance; and, in the crescent moon, we can readily discover that the concave side presents a rugged edge. It can hardly be surprising, then, that the instincts of genius should in this, as in other departments, anticipate the discoveries of science. Democritus propounded the idea of the spots on the moon being diversities of surface, consisting of mountains and valleys, seas and rivers. The Orphic Hymns went further, by ascribing cities with a teeming population. The power of the telescope was, however, required to bring out in relief the diversities of surface, which make the moon the counterpart of our own globe.
To those who have not had the opportunity of examining the moon through a telescope, the stereoscopic pictures of Mr Warren De la Rue form an admirable substitute. Indeed, to the unscientific eye, the stereoscopic picture gives a much truer idea of the configuration of the body. The reason is simple. We have not, in looking through the telescope, the aids of perspective, which we possess, when looking at any terrestrial object; and, consequently, there is difficulty in bringing out in relief the mountain ranges, peaks, and rims of craters. Sometimes, the moon, to the unpractised eye, appears a uniform level; at others, the relief is reversed, the mountain sinking into a cavity, and the sharp peak into a perforation. The stereoscopic views of the moon, however, remedy all this:
