No boy should be unable to swim, because it is essential to the preservation of life; but the attainment of the art has been held to be difficult, and the number of good swimmers is very small. The whole science of swimming consists in multiplying the surface of the body by extensive motions, so as to displace a greater quantity of liquid. As the first requisite of oratory was said to be action; the second, action; and the third, action; so the first, second, and the third requisite in learning to swim, is COURAGE. Now there is a vast difference between courage and temerity; courage proceeds from confidence, temerity, from carelessness; courage is calm and collected, temerity is headstrong and rash; courage ventures into the water carefully, and throws himself off with a firm and vigorous lounge forward, and a slow and equable stroke; temerity begins to dive before he knows whether he can swim or sink, and after floundering about for a minute or two, finds that he can swim farthest where it is deepest. Therefore, let the young swimmer mark the distinction between courage and temerity, and he will speedily become a swimmer. Before, however, we proceed to offer any remarks on swimming as an art, we cannot refrain from calling the attention of our young friends to the observations of a celebrated medical doctor who has thought profoundly on the subject. "Immersion in cold water," says he, "is a custom which lays claim to the most remote antiquity; indeed it must be coeval with man himself. The necessity of water for the purpose of cleanliness, and the pleasure arising from its application in hot countries, must have very early recommended it to the human species; even the example of other animals was sufficient to give the hint to man; by instinct many of them are led to apply cold water in this manner, and some, when deprived of its use, have been known to languish, and even to die." The cold bath recommends itself in a variety of cases, and is peculiarly beneficial to the inhabitants of populous cities who indulge in idleness and lead sedentary lives: it accelerates the motion of the blood, promotes the different secretions, and gives permanency to the solids. But all these important purposes will be more easily answered by the application of salt water; this also ought not only to be preferred on account of its superior gravity, but also, "for its greater power of stimulating the skin, which prevents the patient from catching cold."