CHAMBERLIN— THE AGE OF THE EARTH. 259 



volume very slowly from a small beginning, that the solutions came 

 from three sources and were variable from the start, so that the whole 

 history was very different from the preceding. The three sources of 

 solutions were (i) the internal metamorphic action of waters en- 

 trapped in the growing accessions, (2) surficial action by the atmos- 

 phere and hydrosphere acting on the shell of the lithosphere, and (3) 

 accessions of water- substance from the environing sphere under con- 

 trol of the sun — particularly accessions through the system of ex- 

 change between the ultra-atmosphere of the sun and the ultra-atmos-' 

 phere of the earth.^^ The first source brought one type of solutions, 

 the second another, and the third added water that was essentially 

 fresh. Under this view it is obvious that until this complex of 

 sources and variations has been worked out the present rate of acces- 

 sion has no claims to be regarded as a trustworthy divisor for ascer- 

 taining the total period of activity. 



There are also two rather radically different methods of dealing 

 with the geo-chemical evolution of the ocean. These are not neces- 

 sarily connected with the preceding dift'erences of view, but as a 

 matter of fact they are closely associated with them. 



The first of these — associated with the older cosmological view — 

 takes for its start the concept of a universal crust acted upon from 

 without by an atmosphere and hydrosphere, for its middle factor the 

 streams, and for its end-products the sediments and the ocean. The 

 matter in the sediments and in the ocean taken together are supposed 

 to match the loss of the crust by decomposition and wear. Under 

 this view any real failure to so match is a discrepancy to be accounted 

 for. In the special problem in hand the sodium in the ocean, together 

 with the sodium that remains in the sediments, should match the 

 sodium once in the denuded rocks of the crust. So, also, the other 

 elements of the crust should appear in due proportion in the sediments 

 and the ocean. It is recognized in the cases of calcium, magnesium, 

 potassium, silica, and other elements that there are reversals of action 

 by which these elements go back into the solid state as new sediments, 

 but it is held that sodium does not return to the solid state in the 

 sediments in a similar chemico-physical cyclic way, to any appreciable 



15 "The Origin of the Earth," The University of Chicago Press (1916), 

 pp. 19-21. 



