260 SCIENCE IN SHORT CHAPTERS. 



shines a warning upon our gay young world, telling her 

 that 



Let her paint an inch thick, to this favor she must come 



that the air and ocean must pass away, that all the living 

 creatures of the earth must perish, and the desolation shall 

 come about in this wise. 



At present, the interior of our planet is described as a 

 molten fluid, with a solid crust outside. As the world 

 cools down with age, this crust will thicken and crack, and 

 orack again, as the lower part contracts. This will form 

 rainures, i.e., long narrow chasms, of vast depth, which, 

 like those on the moon, will traverse, without deviation, 

 the mountains, valleys, plains, and ocean-beds; the waters 

 will fall into these, and, after violent catastrophes, arising 

 from their boiling by contact with the hot interior, they 

 will finally disappear from the surface, and become ab- 

 sorbed in the pores of the vastly-thickened earth-crust, and 

 in the caverns, cracks, and chasms which the rending con- 

 traction will open in the interior. These cavities will con- 

 tinue to increase, will become of huge magnitude when the 

 outside crust grows thick enough to form its own support- 

 ing arch, for then the fused interior will recede, and form 

 mighty vaults that will engulf not the waters merely, but 

 all the atmosphere likewise. 



At this stage the earth, according to M. St. Meunier, will 

 be a middle-aged world like the moon; but as old age ad- 

 vances the contraction of the fluid, or viscous interior be- 

 neath the outside solid crust will continue, and the rain- 

 ures will extend in length and depth and width, as he main- 

 tains they are now growing in the moon. This, he says, 

 must continue till the centre solidifies, and then these 

 cracks will reach that centre, and the world will be split 

 through in fragments corresponding to the different rain- 

 ures. 



Thus we shall have a planet composed of several solid 

 fragments held together only by their mutual attractions, 

 but the rotary movement of these will, according to the 

 French philosopher, become unequal, as "the fragments 



