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230 THE EARTH'S INTERIOR. 



lable weight. Hence the last word of modern 

 science on the existing condition of our eartli's 

 centre seems to be just tliis; our planet consists 

 of a cool and fairly solid but lighter crust poised 

 upon the top of a very rigid, hard, and immensely 

 hot core, which would be liquid and molten, but 

 for the unspeakable pressure of the thick crust 

 piled heavily above it. 



It is a great comfort to think that, after all — 

 at least as far as science has yet gone — we need 

 not give up the solid earth which we all flatter 

 ourselves is so safe and secure beneath our feet. 

 True, science, like the world itself, is always 

 moving, and it has an awkward habit, in all these 

 abstruse matters, of unsaving to-morrow what it 

 told us yesterday. Just as we are beginning to 

 think we have really learnt its last lesson quite 

 correctly, it comes upon us unawares with some 

 strange and contradictory fresh solution, upsetting 

 all the ideas we have been one moment before 

 congratulating ourselves upon having fairly mas- 

 tered. But for the present, at least, we may go 

 to sleep in comfort, as men still do upon the flanks 

 of a volcano, consoling ourselves with the reassur- 

 ing thouglit that if our planet is all one fiery mass 

 within, it is, at least, of solid, not of liquid fire. 

 And, indeed, this conclusion, like most other final 

 conclusions, has a great concinnity and neatness 

 about it. For, if we regard the world as a whole, 



