266 T. C. Chamberlin — Jones's Criticism of 



seismic vibrations themselves are concerned, they simply 

 show the presence of the elastico-rigid property under 

 existing conditions. They tell nothing directly as to 

 what might or might not be the state of the interior under 

 other conditions. As a first step toward reaching the 

 wider meaning we must consider what the existence of 

 the disclosed state of rigidity and elasticity signifies 

 under all the heat, pressure, differential stress, and coop- 

 erative influences that now affect the outer seven-eighths 

 of the earth's body. We must bear in mind further that 

 these conditions are inherited from a previous chain of 

 conditions that ran back as far as geologic inheritances 

 go, and that this brings in the effects of the time factor. 

 Now looking at the matter from the positive or construc- 

 tive point of view, the case may be put this way : 



The outer seven-eighths of the earth is to-day elastico- 

 rigid — to a degree not determined by the seismic waves — 

 notwithstanding all the heat, all the pressure, and all the 

 differential stresses within it, together with all cooperat- 

 ing effects, as also any help that may have been inherited 

 from past geologic time. 



Or, from the negative or destructional point of view, 

 the case may be put in this way : 



All the differential stresses in the outer seven-eighths 

 of the earth's body, all the heat and pressure in this part, 

 and all cooperating effects, together with any help that 

 may have been inherited from past geologic time, have 

 not proved sufficient to destroy the elastic and rigid prop- 

 erties of this part of the earth. 



Now these existing conditions are not simply those that 

 prevail at some one horizon but those that exist in all 

 parts of the outer body of the earth. They undoubtedly 

 include stress-differences of quite different orders of 

 magnitude, some of which are presumably high. Their 

 significance, therefore, is not to be escaped by academic 

 assumptions about dependence. 



The seismic waves have a peculiar value in that they 

 search out the special states of matter in the various 

 parts of the interior. Their cumulative evidences have 

 now practically shut out the molten state from serious 

 consideration in present-day problems, such as the 



