[Illustration: _In 1900 the U. S. Navy commissioned its first submarine, the USS_ Holland, _which was built by John P. Holland. It is shown in dry dock at Perth Amboy, New Jersey, in 1898._] [Illustration: _The USS_ Plunger, _named after an early John Holland submarine, which is an example of the Navy’s present fleet of nuclear submarines._] In the waters of the seven seas are enough deuterium and tritium to power tomorrow’s thermonuclear power plants[1] for millions of years. These rare, heavy varieties of hydrogen, enormously abundant in the vastness of the sea, comprise an energy source without limit for all nations, which need only develop the technological ability to extract them and put them to work. Energy for Exploration For this exploration, men need to put instruments, navigation beacons (see figures on pages 46 and 47), and other devices on the deep ocean floor, where they must operate for long periods of time unattended and with no external source of power. Radioisotope-powered generators, capitalizing on the energy of disintegrating radioactive atoms, are almost the only devices capable of fulfilling these requirements.[2] Man also wants to do productive work under the ocean, such as drilling seafloor oil wells, mining, and salvaging for profit some of the tens of thousands of cargoes lost at sea during thousands of years of ocean commerce. Eventually, he even wants to farm the ocean floor. [Illustration: _An artist draws (using pencil and frosted plastic sheet) the position of objects in the wreck of a 7th century Byzantine ship 120 feet down in the Aegean Sea. Nuclear power will permit historians of the future to remain underwater for long periods exploring shipwrecks or old cities far below the surface._] All these activities require energy—energy in an environment where most sources cannot be applied. Above all, man wants to go down himself to explore, to work, and perhaps to direct nuclear-powered robots to do even more work. This means that small, manned, nonmilitary submersibles will be needed—vessels whose endurance should not be limited by the short life of traditional power sources, but should draw on the fissioning atomic nucleus, harnessed in small reactors.[3] To work effectively in any environment, we must first know and understand it. This is the job of science. In the quest for knowledge and understanding of the ocean, nuclear energy provides scientists with better instruments to put down into the depths and wholly new techniques for the direct study of the many oceanic processes.