program related to the Wahoo event. The Atomic Energy Commission supplied part of the funds for the operational cost of the Rehoboth and in return the Rehoboth was made available for use by the University of Washington Laboratory of Radiation Biology, an AEC contractor, for the period May 3, 1958 to May 20, 1958, to conduct a radiobiological survey. Bight U. S. Navy Hydrographic Office personnel, under the di- rection of Mr. Alfred W. Anderson, made oceanographic surveys during both phases of the investigation and provided the authors with the water samples from four locations for measurementof radioactivity. A radiation monitoring team from the Radiation Technical Division of the Naval Medical Research Institute, J. W under the direction of Lt. Duckworth, measured the radioactivity of water at the surface, at the intake to the ship's evaporators, and at designated depths from the surface down to 600 feet. The surface measurements were made with a survey meter and the measurements of the inflow water to the evaporators were made with a specially designed ion-chamber that was fitted around the intake line. For measurements at depth a gamma scintilation-type probe with a continuous recording device was used. The probe was a modified "well-logging" type provided by the AEC Health and Safety Laboratory, New York Operations Office. A report of these measurements is being prepared for publication by the Naval Medical ResearchInstitute.