DIASTROPHISM AND THE FORMATIVE PROCESSES 393 
take them with it. It is not at all surprising, therefore, that, even 
in the most sincere endeavor to give true shape to a new issue 
under a new view for the purpose of a candid and hospitable test, 
some of the derivatives of the old view should unconsciously slip 
in and be treated as though they were offspring of the new. This, 
in reality, vitiates the whole test. The problem that has thus 
actually been fashioned and put to trial is a hybrid; it is not a true 
problem under either the old or the new view. For example, under 
the theory of a gaseo-molten earth, it was logically assumed that 
each spherical layer of the earth’s interior was homogeneous; and 
hence it had a definite ‘““melting-point.”* There followed closely the 
inference that the material of such a layer must have a common 
state, either liquid or solid. From these logical derivatives of the 
primary assumption, far-reaching inferences were drawn in perfect 
consistency, and these, by years of association, have been woven 
into the web and woof of current thought with little consciousness 
that they are only dependencies of a cosmological postulate. 
But if, on the other hand, the material of all such layers is 
very heterogeneous chemically, because it is an intimate mixture of 
planetesimal débris laid down at random, the logical inference is 
that each layer embraces a wide-ranging group of solution tempera- 
tures and has no single point of liquefaction. If it is subjected to a 
rising temperature, this would, at any given stage, cause the lique- 
faction of only that fraction of the material which was susceptible 
of liquefaction at the temperature reached, not the ‘‘melting”’ of the 
whole layer. ‘This fraction would naturally be scattered throughout 
the mass of the layer and would give rise only to interstitial 
liquidity. The solution temperatures of the larger portion of the 
layer would not yet be reached, and this portion would remain 
solid. Now if the working mechanism of the body is so actuated 
by the joint force of internal and external stresses that graded 
pressures are brought to bear, greater below than above, and more 
or less intermittent, the disseminated liquid is likely to be kneaded 
out of the layer in the direction of least resistance and so leave 
the residue solid. 
‘In revised terms, as applied to interior conditions, a solution temperature or a 
narrow group of temperatures at which the constituents enter into mutual solution. 
