In the frame of mind which these speculations induce--not very greatly alarmed about such extraordinary contingencies, yet not insensible to the solemnity of the thought of what may come to pass even before our living eyes--it is curious, and not necessarily unpleasant, to consider what might be the actual phenomena attending a cometary collision. We know not what comets are composed of, but are certain that they consist of some palpable matter, however diffused, for they observe the rules of motion in their revolutions round the sun. On the whole, the most plausible supposition as to their composition, is that which regards them as watery vapour or cloud, of great tenuity. How like, for example, to the doings of a cloud, is the splitting into two, which has been occasionally observed in them! Well, if they be clouds, the coming of one into contact with our earth would most likely deposit with us an immense addition to our stock of water. It would be instantaneous, or nearly so. Only think of a sudden fall of water sufficient to raise the ocean a hundred feet, and submerge all parts of the land which were less than that height above the present level of the sea! There would, of course, be a fearful abridgment of our continents; all big islands would be made little; and many littler ones would cease to be. The surviving lands would be so swept by the flood, that scarcely any of the present features would remain unchanged. All animals and movable things would be engulfed. In a few minutes, this brawling, chattering, bustling world would be stilled in universal death. What a settlement of 'questions' there! What a strike of work! What a command of Silence!