The daily morning journal and courier., 1907-11-14
TIE INTERIOR
 OF THE EARTH Our Planets Core is Li- quid Yet as Rigid
 as Steel. ENORMOUS PRESSURE Neither Rock Nor Metal Could Keep Solid
 There.
ENORMOUS PRESSURE

TlsMeelea that the interior of the globe is composed of flowing lava has ] long since been abandoned, but -he picture that modern science differs of the inside of the earth is hardly less appalling. All investigations unite 10 prove that the heat increases as we at such rate that forty or fifty miles down no substance with which we Gre acquainted could remain unmelted. And yet the same science tells us that the core of the globe is enormously more rigid than the hardest steel This apparent contradiction is due to the tremendous pressure inside the earth. No rock and no metal can re- main there in the state in which we see 1t on the surface Its molecules must lose the adherence charaeterls- tic of solid bodies in consequence of the heat, but still they are not free to flow like an ordinary liquid, because of the compression to which they are subjected
 The phenomena of earthquakes have given wonderful information about the internal state of the globe. All observations show that the shocks of earthquakes are confined to a thin upper shell They originate at a depth of only a few miles at the most. But the vibrations which they set go- ing are felt all through the earth, of- ten extending to the antipodes. The great ore, held rigid by the pressure, is extremely elastic, and it responds to a shock like bah of steel or of glass. The density of the earth increases toward the center. It is only In ,he Iuper part of the crust that local movements can take place, causing shocks and changes of level at the lsurface. Deeper down everything is lgripped and immovable, except, as aI- ready remarked that the molecules Of the rocks and metals there are sub- ject to vibration like those of bell lagainst which a blow is struck.
 1 But this is not all. Whenever a To- cal release from the pressure is brought about by changes near the surface the potentially liquid but ef- fectually solid core at that point may suddenly become fluid and gush forth through volcanic throat or other vent. But such effects cannot extend to any great depth. Nothing comes to us from the vast interior mass. That remains perpetual mystery, far beyond the searching hand of sci- enoe. Indirectly however, we may llearn much about it. Astronomical considerations throw a great deal of light upon the subject. We see that through the planetary sytem rotating globes are flattened at the poles. The same thing is true of the earth. |
 equator bulges; it's polar regions are drawn inward Mechanical laws as- Isure us that the cause Is to be found in the fact that the earth and the oth- CT planets have assumed shape under 1.-the influence of the centrifugal force of their rotation. That force is ne- cessarily greatest at the equator. Be- Lginning as completed molten bodies, they have commenced to solidify at the surface after having assumed an elli1ordal form due to their rotation.
 Another very significant fact is that kthe shape of the earth corresponds with that which a globe rotating with It's velocity would have if composed of materials arranged to their density that is to say, growing denser to- ward the center. The heaviest mate rials must be deep down in the globe; the lighter materials have remained at the surface. This again corresponds with the facts of observation. We know the total weight" and the aver awe density of the earth. It weighs" six sextillions of tons, and its average density is five and half | times that of water. But the sub- stances composing the crust of the earth have an average density of twice that of water. It follows that the heaviest things in the earth, on 1.-the average, exist deep, within It's ex- terior. For all that we can tell, it's inner core may be wholly metallic. At the center there Is probably an ehormous aggregation of dense metal iAC SuDSIduCCS'
 An indication that the inner parts l,of the earth consist largely if not mainly of iron is to be found in the magnetism of the globe. The earth Is a great permanent magnet. If we could learn the facts it might turn out that iron is the most abundant substance in the solar system and per- hans in the whole universe. The ma Idority of the meteorites that iaG upon the earth consist of solid iron. Blow the earth to pieces and in the result | ing cloud of fragments the rocks that we are familiar with would be almost imperceptble. There would be a rain of iron and other metals descending upon the moon and upon any other attracting body in the vicinity.
 This view of the interior of the globe disposes of the notion, so pictur- esqgely developed in one of Jules IVerne's romanees, Of the existence of vast cavernous openings in the inte- rior of the earth. Such void spaces, though on no large scale, may exist
 in the upper part of the crust but not at a great depth. The earth is ef-
 Actively more solid than a con
 non ball, and the movable rocks com
 posing its crust are like a film of rus