SHAPING THE EARTH BOWIE 337 



impossible for the earth to collapse. The earth is like a solid rubber 

 ball which will yield and chan<^e its shape to forces that are exerted 

 upon it. The earth is a globe almost splierical, approximately 8,000 

 miles in diameter. The number of cubic miles of material in the 

 earth is great, but this large globe j'ields in a surprisingly easy 

 manner to the forces tluit are acting upon it. 



OBJECTIONS TO THE CONTRACTION HYPOTHESIS 



Geologists and other students of the earth have for generations 

 sought for the forces which may have disturbed the earth. Manj^ 

 ideas have been advanced and some of them have had wide accept- 

 ance. One of these is that the earth's interior is losing heat rather 

 rapidly, while the outer portion of the earth, the crust, is maintaining 

 its temperature. In consequence, there is a shrinkage of the interior 

 of the eartli and a collapse of the crust, which causes earthquakes 

 and elevates mountains and plateaus. This process is also held by 

 some to be the cause of oceans and continents. It seems to me that 

 a careful analysis of this hypothesis will lead one to the conclusion 

 that it can not be true. The earth has been likened to an apple 

 or potato. Every one knows that a baked potato or a baked apple 

 has wrinkles in its skin. The contraction hypothesis implies that 

 the nucleus of the earth is like the interior of the apple or potato 

 and that the crust of the earth is like the skin, but the skins of 

 the apple and potato have practically no weight, and, therefore, 

 during the cooking the shrinkage of the interior, due to loss of 

 moisture, makes the skin wrinkle to fit the reduced size of the interior 

 of the apple or potato. 



The crust of the earth certainly can not be likened to the skin 

 of the apple or potato. In the first place, the crust is about 60 miles 

 in thickness and is composed of heavy rock. Then, again, this 

 material is so heavy that no wrinkles could possibly form which 

 would have voids under them like the voids under the wrinkles of 

 the apple and potato. There can be no such thing as a buckling 

 or crumpling of the earth's crust on a shrinking interior. If the 

 interior of the earth is losing heat, while the crust of the earth 

 is maintaining its temperature, the loss of this heat must be so 

 exceedingly slow that there can be no chance for stresses to accumu- 

 late to such an extent as to cause great horizontal forces. I believe 

 that if in the course of geological time, measured by hundreds of 

 millions of years, the earth's interior should cool and contract, the 

 crust would continue to be in contact with the interior and, therefore, 

 the crust would merely be thickened rather than buckled into ridges 

 and troughs. Much has been written against the contraction hypoth- 

 esis, notably by Mellard Reade and Alfred Wegener. 



