In the deep plunge, which is used where it is known that there is depth of water, the swimmer has his arms outstretched, his knees bent, and his body leant forwards (Plate XXVI. fig. 1,) till the head descends nearly to the feet, when the spine and knees are extended. This plunge may be made without the slightest noise. When the swimmer rises to the surface, he must not open his mouth before previously repelling the water. In the flat plunge, which is used in shallow water, or where the depth is unknown, and which can be made only from a small height, the swimmer must fling himself forwards, in order to extend the line of the plunge as much as possible under the surface of the water; and, as soon as he touches it, he must keep his head up, his back hollow, and his hands stretched forward, flat and inclined upward. He will thus dart forwards a considerable way close under the surface, so that his head will reach it before the impulse ceases to operate. (Plate XXVI. fig. 2.) DIVING. The swimmer may prepare for diving by taking a slow and full inspiration, letting himself sink gently into the water, and expelling the breath by degrees, when the heart begins to beat strongly. In order to descend in diving, the head must be bent forward upon the breast; the back made round; and the legs thrown out with greater vigour than usual; but the arms and hands, instead of being struck forward as in swimming, must move rather backward, or come out lower, and pass more behind. (Plate XXVII. fig. 1.) The eyes should, meanwhile, be kept open, as, if the water be clear, it enables the diver to ascertain its depth, and see whatever lies at the bottom; and, when he has obtained a perpendicular position, he should extend his hands like feelers. To move forward, the head must be raised, and the back straightened a little. Still, in swimming between top and bottom, the head must be kept a little downward, and the feet be thrown out a little higher than when swimming on the surface (Plate XXVII. fig. 2); and if the swimmer thinks that he approaches too near the surface, he must press the palms upwards. To ascend, the chin must be held up, the back made concave, the hands struck out high, and brought briskly down. (Plate XXVII. fig. 3.) [Illustration: _Plate XXVI_ _Page 98._ Plunging] [Illustration: _Plate XXVII_ _Page 98._ Swimming—Diving.] [Illustration: _Plate XXVIII_ _Page 99._ Swimming—Thrusting.] THRUSTING.