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POPULAH SCIENCE REVIEW. 
compounds in the interior of the earth, in order to account for 
the high mean specific gravity (5^) of the total mass of the globe. 
In reviewing the evidence which has thus been brought for- 
ward ‘ pro et contra ’ the various hypotheses advanced in reply 
to the question, ‘ What does the interior of our globe consist 
of?’ with which we started, the balance of argument appears 
to be in favour of the older theory, that the earth is a central 
molten mass surrounded or enclosed by a comparatively thin 
solid crust or shell ; and, further, seems to indicate the probabi- 
lity that its interior, besides consisting mainly of molten silicates, 
also contains a great accumulation of the heavy metals and 
their compounds. 
Having now summed up the evidence, the verdict is left to 
be delivered by the jury of our readers. 
