Abstract : In March of 1962, an array on which are mounted 144 metallic and non-metallic samples will be exposed in the Tongue of the Ocean area (TOTO) in the Bahama Islands at a depth of approximately 5500 feet. The main objectives of these studies are two-fold; first, to obtain long term corrosion data on a number of basic engineering materials at great depths, so that this data may be correlated with the voluminous corrosion data available for similar materials when exposed at or near the surface of the ocean, and second, to evaluate the various components of the complete test system. Additionally, methods of corrosion mitigation are included to determine their relative effectiveness at these depths. (Author)