In the plains, what with a low power appeared smooth as a water surface becomes, under greater magnification, a rough and furrowed area, here gently undulated and there broken into ridges and declivities, with now and then deep rents or cracks extending for miles and spreading like river-beds into numerous ramifications. Craters of all sizes and classes are scattered over the plains; these appear generally of a different tint to the surrounding surface, for the light reflected from the plains has been observed to be slightly tinged with colour, The tint is not the same in all cases: one large sea has a dingy greenish tinge, others are merely grey and some others present a pale reddish hue. The cause of this diversity of colour is mysterious; it has been supposed to indicate the existence of vegetation of some sort; but this involves conditions that we know do not exist.
The mountains, under higher magnification, do not present such diversity of formation as the craters, or at least the points of difference are not so apparent; but they exhibit a plentiful variety of combinations. There are a few perfectly isolated examples that cast long shadows over the plains on which they stand like those of a towering cathedral in the rising or setting sun. Sometimes they are collected into groups, but mostly they are connected into stupendous chains. In one of the grandest of these chains, it has been estimated that a good telescope will show 3000 mountains clustered together, without approach to symmetrical order. The scenery which they would present, could we get any other than the “bird’s eye view” to which we are confined, must be imposing in the extreme, far exceeding in sublime grandeur anything that the Alps or the Himalayas offer; for while on the one hand the lunar mountains equal those of the earth in altitude, the absence of an atmosphere, and consequently of the effects produced thereby, must give rise to alternations of dazzling light and black depths of shade combining to form panoramas of wild scenery that, for want of a parallel on earth, we may well call unearthly. But we are debarred the pleasure of actually contemplating such pictures by the circumstance that we look _down_ upon the mountain tops and into the valleys, so that the great height and close aggregation of the peaks and hills are not so apparent. To compare the lunar and terrestrial mountain scenery would be “to compare the different views of a town seen from the car of a balloon, with the more interesting prospects by a progress through the streets.” Some of the peculiarities of the lunar scenery we have, however, endeavoured to realize in a subsequent Chapter.