We have given an epitome of the development of the submarine vessel up to the opening of the twentieth century. It had now reached a successful status of achievement and during the early years of that century was to display a remark able progress. Holland and Lake may be looked upon as the parents of the modern development of the submersible boat, their designs being at the base of the great European progress.

France took up the work actively, its most successful early vessel being the "Narval," built in 1899. This was 118 feet long by 8 feet 3 inches beam, 106 tons surface and 168 submerged displacement. She was a double-deck vessel controlled by Lake hydroplanes, and had installed steam power for surface travel and electric power for undersea work. The French at this time kept their methods secret, and no useful type had been developed in England, the result being that a plant was provided for the building of Holland boats in that country. Germany used the Lake devices, which had not been patented in that country and were made use of by the Krupps. Thus it appears that the modern submarines, as now built and used in the navies of the world, owe their success to principles of construction and devices for control originated and developed by American inventors.