A gravity-type coring apparatus, which is used on the research vessel E. W. Scripps of the Scripps Institution of Oceanography for taking sediment samples of the ocean floor, is described. With this instrument more than 200 cores have been taken in many types of sediment. The 174 mud cores have an average length of 6 feet, 3 inches and a maximum length of 16 feet, 9 inches.
Data from a number of experiments and from field coring operations were analysed in order to improve the design of the device and to permit proper interpretation of core samples. A detailed study was made to explain the observation that the length of the cores averaged about 50 per cent of the depth of penetration of the core barrel. Laboratory coring experiments using mud of uniform water content show that, as the core barrel penetrates the mud, progressively smaller increments of core are added throughout the entire depth of penetration. However, studies of cores taken on a tidal flat and others obtained in field operations show that the size of core increments per unit of penetration remains practically constant with increasing penetration.