A. Because the earth is a bad conductor of heat; and, therefore (although the ground be frozen) the frost never penetrates above an inch or two below the surface.
Q. Why is the earth (below the surface) cooler in summer than the surface itself?
A. Because the earth is a bad conductor of heat; and, therefore, (although the surface be scorched with the burning sun) the intense heat cannot penetrate to the roots of the plants and trees.
Q. Shew the wisdom of God in making the earth a bad conductor.
A. If the heat and cold could penetrate the earth (as freely as the heat of a fire penetrates iron), the springs would be dried up in summer and frozen in winter, and all vegetation would perish.
Q. Why is water from a spring so cool in summer?
A. As the earth is a bad conductor, the burning rays of the sun can penetrate only a few inches below the surface; in consequence of which, the springs of water are not affected.
Q. Why is it cool under a shady tree in a hot summer’s day?
A. 1st—Because the overhanging foliage screens off the rays of the sun: