There is still other objection to this theory. Experiments have been made with various materials to ascertain the change affected in them by heat. It is found that a block of granite five feet long, by a change of ninety-six degrees in temperature, is expanded .27792 of an inch; crystalline marble, .03264; sandstone, .0549. If, then, a portion of the earth’s crust ten miles in thickness be heated six hundred degrees, its crust would be raised two hundred feet; or a change of one degree, the rate of expansion being fairly uniform to five hundred or six hundred degrees, would raise the surface four inches. How important this matter is may be better understood when we consider that if the interior of the earth be a uniformly molten mass, with a crust ten miles thick, a contraction of one-twelve thousandth of an inch should force out of the crust a cubic mile of lava. We should find then a change in temperature one forty-eight thousandth of a degree should effect this, if the crust were ten miles thick. We are then forced to conclude that the earth is not cooling to any appreciable extent; or that the liquid interior is still capable of indefinite compression without necessarily being forced out through orifices in the crust; or that the interior is not a uniformly molten mass. Such are the arguments against a melted interior. The reader should avoid the assumption of a uniform rate of contraction or expansion of heat. Within very narrow limits, such a hypothesis may be allowed; but to assume that it is universal, would be to affirm that if you could only make the earth cold enough it would shrink to nothing at all! The earth and the temperature would swallow each other, like the two snakes, till neither was left. To illustrate more seriously, suppose a race of men existed whose only experience of temperature ranged between forty and two hundred degrees. They could consistently calculate, from the change of water between these limits, that it would require a temperature of many thousands of degrees to expand it to seventeen hundred times its bulk. Yet we know they would have to raise it only to two hundred and twelve degrees to produce the required effect. And if they could go below forty degrees, they would be astonished to find that water then expanded instead of contracting. That the earth, if it cools, does so very slowly is clear, from the character of the materials thrown out. Lava from Mt. Ætna has been observed slowly moving nine months after the eruption. Lower portions of the beds have been found to be abnormally heated ten years after pouring out. Compare the thickness of a lava bed with the depth from which it is thrown, and it will be seen that little heat is lost in the subterranean depths. One instance, showing how slowly the lava is to part with its heat, may be given: