686 T. C. CHAMBERLIN 



solution curve, whatever that might happen to have been for the 

 time being under the local conditions of pressure, state of strain, 

 nature of material, means of escape, and other properties that 

 affected liquefaction and extrusion. It was regarded as essen- 

 tially a curve of equilibrium between solidity and liquefaction accom- 

 modated to the conditions present at each depth and at each stage 

 and was maintained automatically. The actual curve as thus 

 assigned continued always to be essentially the liquefaction curve 

 after that was once attained. 1 The view excludes automatically 

 all internal temperatures higher than the local liquefaction tem- 

 peratures and of course excludes all pervasive gaseous conditions 

 except that of the interspersed and occluded gases of the mixed 

 mass. These interspersed gases assisted extrusion and hence 

 were among the parts most freely extruded. All theoretical 

 inferences based on temperatures higher than the temperatures of 

 liquefaction are excluded from consideration under this view by 

 its very terms. 



Certain structural conditions postulated by the planetesimal 

 hypothesis greatly favored this automatic action. The infalling 

 matter was assumed to have built itself up in a very heterogeneous 

 manner with the result that the mass of the earth was an intimate 

 mixture of all the kinds of material that made up the spiral nebula 

 from which it was supposed to have been gathered. As this mixed 

 matter was heated by compression, some parts of it must certainly 

 have reached temperatures at which they could go into mutual 

 solution or into fusion while as yet other closely associated parts 

 had not reached temperatures that permitted such action, and as 

 the rise of temperature was very slow by the terms of the hypothe- 

 sis the passage of successive parts into liquefaction was widely 

 separated in time. Fluid parts thus came temporarily to be inti- 

 mately mixed with solid parts. These fluid parts, in the act of 

 passing into solution or fusion, absorbed the necessary energy of 

 liquefaction at the expense of the increasing supply. On their 

 ascent into the crust they heated it. If they lodged there and 

 resolidified they gave up their heat of liquefaction. If they 

 reached the surface the residue of heat, both sensible and latent, 

 was lost. By such liquefaction and transfer these portions served 



1 Op. tit., 567. 



