4I4 THOMAS C. CHAMBERLIN 
73. Since the formation of mutual solutions of rock material 
within the earth affects only such part of the mixed matter as 
becomes soluble under the contacts and conditions present, and 
since the solid state is resumed at or near the surface, magmatic 
generation is the matter of primary moment in the history as well as 
the philosophy of magmatization. Magmatic differentiation belongs 
essentially to the reverse process, and is dependent on the generative 
process. 
74. The temperature curve of the interior, under this view, 
does not depend primarily on cooling from the surface or on the 
arrest of a convectional circulation, but on dynamic action within 
the body itself, starting with the restraints of inherited solidity 
in the clastic matter and adding new restraints at intervals later, 
by transformations of such a nature as to fit a part of the mixed 
material for a higher state of solidity, while a part was liquefied 
and sent to the surface to resume solidity there. 
75. The gases and gas-producing substances entrapped by the 
burial of minutely mixed planetesimal matter should have been 
well-nigh amaximum. Subsequent processes of partial liquefaction 
and extrusion should have set these gases free, and they should 
have joined whatever liquid material was in process of formation. 
The magmas should thus have been rich in gases; sometimes 
becoming explosive. A large gaseous factor is-therefore held to 
be characteristic of the vulcanism of an earth so built. : 
76. On the other hand, during the protracted boiling of a 
gaseo-molten earth, potential gases should have been set free to a 
maximum, and all gases should have been brought to the surface 
by convection, whence they should have escaped to the fullest 
extent consistent with gravity, because of their hot state. There 
should have remained in the boiled liquid merely the equilibrium 
quantity required to balance the partial pressures of the atmos- 
phere.t Laboratory melts of like material under like conditions 
should indicate the limited amount of this. The cooled mass 
could scarcely have carried those abundant supplies of gas that 
have been so amply manifested by the extrusive action of all the 
* Rollin T. Chamberlin, ‘“The Gases in Rocks,” Jour. Geol., Vol. XVII (1909), 
pp. 565-68. 
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