Great Disasters and Horrors in the World's History

by Allen Howard Godbey

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:

In the year 1828 a great mass of ice was discovered on Mt. Ætna. In consequence of the protracted heat of the season, supplies of ice at Catania and the adjacent regions failed entirely, and the people suffered considerably for the want of an article considered necessary to health as well as comfort in that hot climate. The Catanian authorities caused search to be made for some crevasse or natural grotto on Mt. Ætna, where drift-snow might exist. Near the base of the highest cone was found a vast mass of ice, covered by a lava bed. How old it was there is no means of knowing; nor can we tell how much of the ice might have originally been melted by the overflowing current. But there it was, so hard and firm that the workmen quarried it with great difficulty.

Lastly, it appears that the causes of earthquakes and volcanic action must be the same. A violent volcanic outbreak causes earthquake shocks at once, as though relieved by a safety valve. The experiments of Mr. Robert Mallet, the best known authority on earthquake phenomena, tend to prove that the shocks necessarily originate at a comparatively short distance below the surface. So, from two independent lines of investigation, the same conclusion is reached.

These objections have caused inquiry to be made as to what causes might locally develop heat. Here there are so many possible methods that scientists may not be expected to unite. One is the chemical theory: water coming in contact with quick-lime, or metallic sodium or potassium, would evolve intense heat. One or two locomotives have been invented which need no fuel, obtaining their heat supply thus.

But it is objected to this that the products of volcanic action are not such as would result from such a cause; that all experience indicates that water has already penetrated every portion of the earth, the deepest borings always crossing veins, and all great mines requiring to be artificially drained.

One other theory is, that the slow contraction of the globe from the radiation of heat into space necessarily affects the outer portion most directly, and in consequence, the shrinking of the crust at the weakest points produces unusual pressure there, which can evolve intense heat, as is shown by the fact that nearly all rocks so twisted or strained are more or less changed in their internal structure by heat. It is also evident that a region once thus weakened and seriously broken would necessarily form a fairly permanent volcanic tract. As the work of nature all goes to preserve equilibrium or balance of forces, an unusual upheaval would necessitate unusual subsidence near at hand; and in fact the highest mountain is always near the deepest ocean.

This explanation, combined with that of chemical action seems to us the more tenable. None of these theories conflict with the nebular hypothesis of Kant and Laplace.

In looking over the areas of volcanic action, we will find they have changed considerably from the areas of the past.

In the continent of Europe there is but one active volcano—Vesuvius; but there are six others on islands in the Mediterranean. Africa has four active volcanoes on the west coast, and six on the east; while ten others are to be found on adjacent islands. Austria has no volcanoes, so far as is known. In Asia are twenty-four active volcanoes; but twelve of these are on the peninsula of Kamtschatka. On the American continent we find a larger proportion. North America has forty-five, most of which are in Mexico and Central America; and South America has thirty-seven. Of these continental volcanoes all are near the sea, except four which are reported to lie in the great unexplored tableland between Siberia and Thibet; and some are said to exist in the Chinese province of Mantchooria. No white man has visited them.