The fact is that every new invention has its infancy of weakness and failure, its adolescence of partial adoption, and doubtful success, and its manhood of completion and achievement. Unfortunately the natural conservatism of a profession and perhaps of human nature is apt to deride the early failures, and to prejudice the invention so as to delay its adoption. Every inventor can tell stories of the obstruction he has met with, and often of his ultimate triumph, like Mr. Whitworth and his steam hammer pile-driving competition, when he succeeded in driving piles with his steam hammer in as many minutes as it took hours under the method previously adopted, much to the astonishment of the old hands. Certainly the submarine has had its period of failure and ridicule, for the attempt to use submarines dates from very ancient days, as Mr. Fyfe’s interesting historical _résumé_ shows, yet it is only now arriving at the stage of development which forces us to reckon with it as a serious factor in naval warfare. We need not follow Mr. Fyfe in his early history of the submarine, but leaving James I.’s somewhat apocryphal voyage under the waters of the Thames, the inventions of Bushnell, Fulton, Warner, and others, we may come to the Confederate diving boat during the war of secession. Here we have a real diving boat which, though it drowned three crews, did succeed in destroying the United States sloop _Housatonic_, one of the blockading fleet off Charleston, though she was herself sunk in the effort, drowning her fourth crew. It is interesting to compare this submarine boat with one of our modern _Hollands_. The following is the description given by Captain Maury, the well-known hydrographer, then at the head of the Confederate torpedo bureau, of this unfortunate craft, or _David_ as she was called. “It was built of boiler iron, about 35 feet long, and was manned by a crew of nine men, eight of whom worked the propeller by hand, the ninth steered the boat and regulated her movements below the surface of the water. She could be submerged at pleasure to any desired depth, or could be propelled on the surface. In smooth, still water she could be exactly controlled, and her speed was about 4 knots.” It is further stated that she could remain submerged for half an hour “without inconvenience to her crew,” and in action she was to drag a torpedo under a ship’s bottom, which was intended to explode on striking. Now contrast this rude and dangerous craft with the “Holland” boats now building for the British Government, and the advance which has been made in the last forty years is evident.