This exercise is first performed from platforms of various heights, and from walls of various elevations. The object is to lessen the shock that the legs and body experience in reaching the ground at a depth of more than six or seven feet, and to diminish the distance if possible, at the same time that it diminishes the violence and velocity of the fall. All this is easily managed by observing the following rules. Suppose the pupil placed upon a platform of four or six feet in height, he must first examine the place he is about to leap to, so as to select the most favourable part, free from stones and other obstacles. He will then approach the extremity of the platform, with his back towards it, and bend his body, placing his hands in the position shown in Plate X. fig. 3. Having taken up this position securely, he will lean his head a little forward, raise his toes from the platform, and remain for an instant supported by the arms. The body then begins to extend, and the legs to lengthen downward and backwards; the arms follow this movement, bend, and support the body by the hands, which have a secure resting-place on the edge of the platform, as in Plate X. fig. 4. This descending movement is executed as slowly as possible: the arms stretch out to their utmost length, till the body is sustained by the last phalanx of the fingers, or touches the ground with the feet. If it does not reach the ground, the pupil drops gently down on the tips of his toes, bends himself, and recovers his upright position. There is another mode of descending, when the last resting-place for the hands is the top of a counterfort, or prop on a wall without a counterfort. This consists (see Plate X. fig. 3) in seizing the last hold with the right hand for instance, and in hanging firmly by that hand, whilst the left, being at liberty, is lowered and pushes back the body from the projecting stones in the walls, to prevent injury in the descent. The impulse thus given is, however, very trifling, and solely to avoid hurt, without increasing the violence of the fall, which ought to be facilitated on reaching the ground by the rules already given. By these means, the height of a wall is relatively diminished, for a man who hangs suspended by his arms, has six feet less to drop than he who has his feet where he might put his hands. The down leap, unless gradually practised, may produce ruptures of the diaphragm. When, however, the elevation from which the leap is taken is gradually increased, the eye becomes accustomed to measure the most extensive distances fearlessly, at the same time that by practice the abdominal members learn to bend properly under the weight of the trunk, and thereby preserve the organs contained in it from serious injuries. In this kind of leap, the shocks will be diminished by retaining the air in the chest, which may be done by closing the glottis.