What is Inside the Earth?

Southland Times, Issue 12012, 17 December 1907, Page 1 (Supplement)

What is Inside the Earth?

The idea that the interior of the earth is composed of flowing lava has long since been abandoned, says Professor Garret P. Gerviss, but the picture that modern science offers of the inside of the earth is hardly less appalling. All investigations unite to prove that the heat increases as we descend deeper in the terrestrial crust at such a rate that forty or fifty miles down no substance witli which we are acquainted could remain uumelted. And yet the same science tells us that the cere 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 remain there in die state in which we see it on the surface. Its molecules must lose the adherence characteristic of solid bodies in consequence of the heat, hut 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 ill in upper shell. They originate at a depth of only a few miles at the most. But the vibrations which they set going are felt all through the earth, often extending to the Antipodes, as the great core, field rigid by the pressure, is extremely elastic, and it responds to a shock like a ball of steel ‘or of glass. But this is not ail. Whenever a local release from I lie pressure is brought about by changes near the surface the potentially liquid, but effectually solid, core at that point may suddenly become fluid, and gush forth through a volanic throat or other vent. But such effects cannot extend to any great depth. Nothing comes to us from the vast interior mass. That remains a perpetual mystery, far beyond the searching hand of science.