Preface 



jDy the terms laid down for the lectures given in 

 memory of Mrs. Hepsa Ely Silliman, these are "de- 

 signed to illustrate the presence and providence, the 

 wisdom and goodness of God, as manifested in the 

 natural and moral world." 



I believe it is true to say that nowhere on our planet's 

 surface is there less interference by men with the acts 

 of providence than in great ocean depths, where natu- 

 ral laws have reigned supreme for untold millions of 

 years, in fact since the birth of the ocean itself. It 

 therefore seems to me that the subject discussed in the 

 following pages fits well within the frame of the Act 

 of Foundation. 



It is for me a great privilege and honor to have been 

 invited to give the Silliman Lectures of 1952 on "The 

 Floor of the Ocean." The deep ocean has recently 

 come to the foreground of geophysical and geochem- 

 ical investigations, thanks largely to new instruments 

 and new methods of research which were used for the 

 first time by the Swedish Deep-Sea Expedition of 1947- 

 48. About one-half of the planet's total surface, con- 

 siderably exceeding in area all the five continents 



