If rain is not at all seasons pleasant and delightful, neither are rain-clouds among the most beautiful which diversify the landscape of the sky; for it has been well remarked, that “all the fine-weather clouds are beautiful, and those connected with rain and wind mostly the reverse.” What, indeed, can be more striking than the aërial landscapes of fine weather, in which, by an easy fancy, we can trace trees and towers, magnificent ruins and glaciers, natural bridges and palaces, all dashed with torrents of light or frowning in shadow, glowing like burnished silver, glittering in a golden light, or melting into the most enchanting hues? But with all this beauty the eye is seldom capable of judging correctly of the proper size and forms and motions of clouds. The same cloud which to one observer may be glowing with light, to another may be enveloped in shadow. That which appears to be its summit may be only a portion of its outer edge, while that which seems to be its lower bed may really be a portion of its further border. A spectator, on the summit of a tall cliff, may observe what he takes to be a single cloud; while a second spectator, on lower ground, will perceive that there are two clouds. The motions of clouds are so deceptive, that they often seem to be moving in a curve over the great concave of heaven, while they are in fact advancing in nearly a right line. Suppose, for example that a cloud is moving from the distant horizon towards the place where we stand, in a uniform horizontal line without changing either in size or form. Such a cloud, when first seen, will appear to be in contact with the distant horizon, and consequently much nearer to us than it really is. As it advances towards us, it will seem to rise into the sky, and to become gradually larger till it is almost directly overhead. Continuing its progress, it will then seem again to descend and to lessen in size as gradually as it had before increased; till at length it disappears in the distant horizon at a point exactly opposite to that at which it was first seen. Thus the same cloud, without varying its motion in the least from a straight line, and remaining throughout of the same size and form, would seem to be continually varying in magnitude; and the line of its motion, instead of being straight, would appear to be curved. This is one of the most simple cases that can be supposed: but the clouds as they exist in nature do not remain of the same magnitude, but are constantly changing in form, in size, in direction, and in velocity; so that it is quite impossible to form an accurate idea of their shape and size, or to explain their motions. Clouds, at different elevations, may often be seen to move in different directions under the influence of different currents of wind. [Picture: Different appearance of the same clouds to different observers]