to within about a mile of the surface at the New York end of the tube. It is this air which will make all the trouble."
"What in the world has the air in the tube to do with the weight of the passengers in the car?" asked Mr. Curtis, astonished.
"It has everything to do with it," said Dr. Giles. "But that's a subject I do not wish to speak of yet. I myself have no clear idea of how nearly perfect a vacuum I shall be able to produce, and hence my calculations are only the roughest kind of approximations at present."
"Well," said Mr. Curtis, "it will be a great pity if the passengers do not lose their weight. Just imagine, Flora, how you would feel floating around at the center of the earth, like a feather. If you had a tennis-ball in your hand, you could n't throw it anywhere, because the ball would have no weight; and if you brought down your fist with all your might on the most delicate glass vase, you could n't possibly break it, because your hand would have no weight and so would just bounce back."
Dr. Giles laughed heartily. "That's news to me," said he, "I must confess; but then, you know, we all of us learn something new every
