For some time Leatherwing continued flying backwards and forwards, over the upper end of the pond, and seemed determined not to approach the oak-tree. The truth is, that his game, which consisted of gnats and other small insects, was abundant just at that spot, and a very hearty supper he made that evening. I suppose he found the legs and wings of these insects rather dry food, for sometimes, as he skimmed over the water, he would dip in like a swallow, and drink a few drops as he passed, in order to wash them down. While he is eating his supper, I intend to give you a short, and I hope not a very uninteresting description of his curious wings. As for his habits and manner of passing his time, I dare say that he will take care to say something upon that subject himself, when he gets into conversation with Brush, who has just informed us that "old Leatherwing _will_ talk a great deal about his own affairs." Almost every person, whether living in the town or country, must often have observed the bat flitting about trees and houses in a calm summer evening, but many have never taken the trouble to examine him more closely, or have not had an opportunity of doing so. To form a proper idea of the structure of the bat's wings you must understand, that his fore-legs, or his _arms_, as I will call them, are almost as long as his body, and that all the four fingers of his hands are _quite as long as his arms_. Between these immensely long and slender fingers, is stretched, (like the silk on the framework of an umbrella,) a very thin elastic skin, or membrane,[4] which is continued from the tips of the little fingers to the ankles of the hind-legs, and then very nearly to the end of the tail, which is almost as long as his body. So that the animal, when spread out in the flying position, is entirely surrounded with the membrane, except at the head and neck. The toes of the hind-foot, and the thumb of the hand, are not attached to the skin, and are not longer than those of other animals. These are furnished with sharp and hooked claws, so that the bat can cling very firmly to walls and perpendicular rocks. [4] The membrane of the bat's wing appears to possess a most exquisite and inconceivable sensibility. Cruel experiments have proved that this animal, when deprived of the senses of seeing, hearing, and smelling, will still fly about a room, without ever coming into contact with the walls, or with threads stretched across in all directions. Cuvier supposes, that "the propinquity of solid bodies is perceived by the manner in which the air re-acts upon the surface of the wings." This astonishing faculty, which almost indicates the possession of a sixth sense unknown to us, is no doubt of great use to the bat, as it enables him to pursue his rapid zigzag flight in the dark, without fear of striking against the boughs of trees, or other obstacles.