The AEC is, in short, concerned with virtually every facet of basic oceanography, and with study of the sea as a whole, for radionuclides, like their nonradioactive counterparts, can and do become involved in every phase of the vast and complex ocean ecology. In the process of pursuing its research interests, it also provides oceanographers with a whole new family of tools for study. Let us now see how atomic instruments contribute to the growing knowledge of the sea. Oceanographic Instruments [Illustration: _This radioisotope powered swimsuit heater uses plutonium-238 to produce 420 watts of heat. Water, heated by the decay of ²³⁸Pu, is pumped through plastic veins partially visible in the undergarment. The cylinder under the diver’s arm contains 4 capsules of ²³⁸Pu, and a battery-pump assembly is contained in the box at his feet. After preliminary tests at the Naval Medical Research Institute in Bethesda, Maryland, the unit will be used in Sealab III, the Navy’s underwater research laboratory. The heater was developed by the AEC Division of Isotopes Development._] The ocean is both a complex and a harsh environment and its study has always demanded that designers of seaworthy instruments and sampling devices be both ingenious and experienced in shipboard requirements. Until recently, these devices tended to be rugged and simple, if not indeed crude. More refined, electronic instrumentation has begun to appear in recent years, but most designs still fail to pass the test of use at sea. Even among those that do pass, there is persistent difficulty in separating desired information-carrying signals from background and system-induced “noise”. This has been a specific problem with current meters designed to be moored in the open ocean and also with one quite sophisticated gamma-ray detector. To meet the clear need for improved devices, as well as to support its own research and increase utilization of nuclear materials and techniques, the AEC Division of Isotopes Development encourages the development of oceanographic instrumentation. This comparatively young technology already has produced exciting results. The future may be even more revealing as nuclear energy is applied more and more to the study, exploration, and exploitation of the ocean. Instruments that have been developed under the AEC program include a current meter, a dissolved-oxygen-content analyzer, and a sediment-density meter. A new, fast method for determining the mineral content of geological samples also has been perfected.