an easy way of getting rid of it. But have you calculated what an enormous amount of earth you will have to remove from this tunnel,—thousands upon thousands of cubic miles,—a regular mountain of matter, some of it perhaps in a red-hot condition?"
Dr. Giles could not repress a hearty laugh at this vivid picture. "Why, James, where in the world did you get your figures?" he asked. "The tube will be only thirty feet in diameter, internally."
"Yes; but it will be eight thousand miles long."
"True; and do you know how much matter a hole eight thousand miles deep and thirty feet in diameter will contain? It is a very simple calculation; with a pencil and a scrap of paper you can figure out the result for yourself in a few minutes."
"I suppose, then, that you have calculated this amount exactly?"
"Certainly; and the total quantity of materials we shall have to remove in digging our tunnel will not be much more than about one fifth of a cubic mile."
"Only one fifth of a cubic mile!" echoed Mr. Curtis.
"That's all, and it's plenty, let me assure you.
