somewhat; and the greater the speed of the car, the more was it retarded by the resistance of the air.
"Ah, now I begin to understand," said William, thoughtfully. "The reason I had no weight before was because I fell just as fast as the car did, and so could never catch up with the bottom. But now that the speed of the car is checked by the resistance of the air in the tube, the bottom of the car is held back three or four feet every second; and as I am, of course, not held back at all, save by the trifling resistance of the air in the car, I am each second forced three or four feet nearer the bottom. And the faster we go, the more will the car be retarded, and the more I shall, consequently, weigh. As soon as the resistance is sufficient to retard the car thirty-two feet each second, I shall weigh just as much as I did upon the earth, namely, one hundred pounds. If the resistance becomes still greater, I shall weigh even more. When I reach the center of the earth, it is quite possible, as the resistance increases with the square of the velocity, that I may be falling at a sufficient speed for the car to be retarded one hundred and twenty-eight feet each second, in which case I should weigh four hundred pounds!
