(Table, Page 194) Measurement of radium inside a ferromanganese nodule from the Pacific Ocean (Carnegie 7 Expedition)

The radium content of twenty-eight (twenty-seven from the Pacific) samples of ocean-bottom sediments was determined, and similar determinations reported by Joly and Pettersson are included for comparison. These comprise practically all such determinations that have been made, and the paucity of these data in comparison to the extent, importance, and high radium content of the material is emphasized. Those bottoms composed mostly or entirely of red clay generally contain more radium. A mechanism for explaining the high radium content of deep-sea sediments is suggested which does not coincide with the opinions of either Joly or Pettersson.