PREFACE 



Dr. T. Wayland Vaughan until the manuscript was ready 

 for publication. After arrangements had been made for 

 the carrying out of the chemical analyses, parts of the 

 samples of sufficient size were sentto the Sharp-Schurtz 

 Company of Lancaster, Ohio for analysis. 



Although the number of samples examined is rela- 

 tively small, they were collected from a very large 

 area. Besides the seventy-five samples of Pacific 

 deep-sea deposits, a few samples were collected in the 

 Atlantic Ocean and in the shallow-water areas of the 

 Pacific Ocean, but most of these are not described in 

 this report. 



Few determinations have been made on the radium 

 content of materials comprisingocean-bottom sediments. 

 Dr. C. S. Piggot made twenty-eight determinations on 

 samples secured by the Carnegie on her last cruise. 

 The results of his investigations are presented in the 

 second report of the present volume. When the vast 



areas covered by ocean-bottom sediments, and the high 

 radium content of these sediments is considered, it is 

 evident that additional measurements of this kind should 

 be made. 



Dr. Revelle, because of the demands on his time as 

 a commissioned officer of the U. S. Navy, has been unable 

 to give his personal attention to the final reading of the 

 master copy as prepared for publication. The material, 

 however, has been carefully read by the members of the 

 staff of the Department of Terrestrial Magnetism. 



The present volume is the ninth in the series of 

 "Scientific results of cruise VII of the Carnegie during 

 1928-1929 under command of Captain J. P. Ault." It is 

 the second of the Oceanographical Reports. 



J. A. Fleming 

 Director, Department of Terrestrial Magnetism 



