THE BEARING OF RECENT THEORIES ON THE 

 NATURE OF THE EARTH'S INTERIOR UPON 

 THE QUESTION OF DEEP MINING. 



Bv Professor E. H. L. Schwarz, A.R.C.S., F.G.S. 



Geolog-y has inherited many beHefs from mediaeval times,, 

 which still remain part of the creed of those who profess to 

 base their ideas on solid fact. One of the most ingrained of 

 these beliefs is that of a hot. liquid interior of our earth. It 

 was proved to the satisfaction of the Mediterranean nations 

 by the flows of lava from the chimneys of Etna and Vesuvius, 

 and it was the civilisation of these nations which spread and 

 was taken up by the rest of the world, so that ideas started 

 in Italy became the heritag-e of all thinking men. Then Kant 

 and Laplace, with their Nebular hypothesis, put this liquid 

 globe theory on a basis which satisfied every condition then 

 known or imaginable. If, however, we examine the premises 

 of the Laplacian theory; if we put ourselves outside our heredi- 

 tary tendencies and dispassionately review the whole question, 

 we" shall find that all the so-called proofs and reasons for the 

 earth's interior being hot and liquid rest on arguments which 

 will not hold water. The lava of Etna, for instance, cannot 

 come from any profound depths. The gaseous sphere with 

 which Laplace commences his history of the Solar System 

 could not have existed, as the kinetic energy of gaseous 

 molecules would have prevented their being whirled round in 

 a coherent globe; the Solar System, in fact, at the present day, 

 instead of affording testimony in favour of the Nebular 

 hypothesis, contains so many contradictory evidences that a 

 new theory of its origin has become imperatively necessary. 



Not onlv is the philosophy of modern geology destructive 

 of the old idols of theory and hypothesis, but it is constructive, 

 perhaps merely to set up a new idol, but nevertheless the new 

 hvpothesis of the nature of the earth's interior rests on a basis 

 of probable fact and stands four-square to modern knowledge. 

 I refer to Professor T. C. Chamberlin's Planetismal hypothe- 

 sis. I cannot here explain the hypothesis as a whole; it is 

 available to all in the Text Book of Geology published by 

 Professors Chamberlin and Salisbury; suffice it here to state 

 that the theory necessitates the gradual growth of the earth 

 from a small, solid nucleus by the infalling of meteorites and 

 that it is still growing. My purpose in the present paper is to 

 examine some of the results of the physical investigation of 

 the surface of the earth which prove by undeniable evidence 

 the existence of a solid interior of the earth, which we postulate 

 from theoretical considerations if we accept the Planetismal 

 hypothesis; and as none of the processes of earth building- 

 explained by this hypothesis require a hot interior, we are 

 left with presumptive evidence that it is cold. 



In the first place we are now enabled to actually test the 



