Submarine mines may be countermined; when necessary, defied; guns may be silenced and torpedo-boats so riddled by rapid-fire guns that they will be disabled beyond the radius of their effective action; automatic torpedoes may be checked by netting, or by the prompt manœuvrings of the attacked vessel; ship may always fight ship. But what is the chance for brain or brawn against a successful submarine boat, when the mere suspicion of its presence is enough in itself to break down the blithest, bravest heart of oak. It is here that their moral effects are enormous. The history of their development may be briefly told. In 1624 Cornelius Van Drebble, a Hollander, made some curious experiments under the Thames. His diving-boat was propelled by twelve pairs of oars and carried a dozen persons, among them King James I. In 1771 Bushnell, of Connecticut, constructed a boat which Washington described in a letter to Jefferson as being a “machine so contrived as to carry the inventor under water at any depth he chose, and for a considerable time and distance with an appendage charged with powder, which he could fasten to a ship, and give fire to it in time sufficient for his returning, and by means thereof destroy it.” Fulton borrowed Bushnell’s idea, and in 1801 experimented successfully with it in the Seine. He descended under water, remained for twenty minutes, and after having gone a considerable distance, emerged. In 1851 a shoemaker named Phillips launched in Lake Michigan a cigar-shaped boat forty feet long and four feet in its greatest diameter. This was his first attempt, but in the course of a few years he so far perfected his arrangements for purifying the air that on one occasion he took his wife and children, and spent a whole day in exploring the bottom of the lake. In the history of these boats, as told in the report of the Board on Fortifications, Phillips afterwards descended in Lake Erie, near Buffalo, and never reappeared. Many other attempts were made, the most successful being that of a Russian mechanic, who in 1855 built a diving-boat which was under such perfect control that he could remain submerged for eight hours. The boat which sank the _Housatonic_ was a remarkable submarine vessel; it was about thirty-five feet long, built of boiler iron, and had a crew of nine men, of whom eight worked the propeller by hand, while the ninth steered and governed the boat. She could be submerged to any desired depth or could be propelled on the surface. After various mishaps she went out of Charleston harbor, attacked and sank the United States steamer _Housatonic_, then on blockade duty; as she never returned, it is supposed that the reflex action of the torpedo destroyed her. In the report quoted above the results already attained in submarine navigation are thus summarized by Captain Maguire, U.S.A.: