Quite early in man's attempt to penetrate into the great secrets of the earth, when he tried to find its hidden treasures of gold and diamonds for the purpose of trade, he learned one important fact, namely.
That it grows hotter as you descend. This is evident also, from the hot springs found in different parts of the world, and still more evident from the volcanoes which cover the country around to a thickness of many feet.
A great authority on the subject has asserted that there are slight earth tremors every quarter of an hour.
The hand of man seems weak indeed when we think of the wondrous power of these mighty forces.