Through the Earth/Chapter XXX

CHAPTER XXX

"DANGER!"

IT really seemed as if William was correct in his surmise, for the weight of bodies in the car kept steadily increasing, and he could now jump from the floor to the ceiling without fear of rising too quickly. In fact, if the increase in weight continued at the same rate, it was evident that bodies in the car would have several times their normal weight before the center of the earth was reached.

Our hero was so fascinated by the idea that he was soon to weigh some four hundred pounds or so that he could not take his glance away from the spring balance for an instant, but watched it with feverish interest. Imagine his dismay, therefore, when, shortly after indicating a weight of four ounces, the needle on the dial began to move backward.

"Why, whatever can this mean?" exclaimed William, in fresh surprise. "Nothing here ever seems to happen the way I expect. Just as I had made up my mind to he the champion heavyweight of the world, bodies begin to grow light again, and with no apparent cause. It is impossible that we can have already passed the center of the earth."

A glance at the telemeter confirmed this impression, for it showed that the car was still quite a distance from the center. What, then, could cause this diminution in the weight of bodies! Only one thing, namely, a decrease in the velocity of the car. But the speed of the car, instead of diminishing, ought to have been increasing every second.

"H'm!" exclaimed William, "here's a fresh puzzle. Objects in the car now seem to be getting lighter and lighter, although I have n't yet passed the center of the earth. It would be a pity if four ounces to the pound were to be the greatest weight I shall have. I was beginning to think that my weight would keep on increasing until I weighed four or five hundred pounds and could n't drag myself about any longer."

There was only one small flaw in our hero's reasoning. He was right in believing that his weight would be greatest when he was traveling fastest, as the resistance of the air in the tube would then be greatest. He was also right in believing that, if there was no air in the tube, his speed would be greatest when he reached the center of the earth. What he overlooked was the fact that, while the increase in the speed of the car each second was now very small, the resistance offered by the air was considerable. In a word, although he had not yet passed the center, his speed was checked by the air more than it was increased by gravity, so that the car was gradually slowing up. He had passed the point at which objects would have their greatest weight, and from now on all bodies in the car would continue growing lighter and lighter.

"Ah, yes," said William, as he slowly realized the true state of affairs; "I begin to see now where I made my mistake. Under no circumstances could I have weighed more than I generally do on the earth, because, if the resistance in any one second had kept back the car more than thirty-two feet, my speed the next second would of course be less than before, since gravity, even when greatest, only increases my velocity thirty-two feet each second. And my speed being less, the resis
"A Warning Sign Appeared, Bearing in Large Black Letters the Word 'Danger!'"

"A WARNING SIGN APPEARED, BEARING IN LARGE BLACK LETTERS THE WORD 'DANGER!'"

tance of the air would be less also. There is no conceivable way in which I could obtain a weight of four or five hundred pounds, and I was a dunce to imagine such a thing possible!"

It seemed a pity to be deprived of the novel experience he had anticipated; but William soon consoled himself, and looked at the telemeter to see what progress he was making. The instrument indicated that the car was now only two hundred miles from the center of the earth, and was falling with the frightful velocity of six miles per second, its speed, however, decreasing every instant.

At this moment our hero was startled by the violent ringing of an electric bell fastened to one of the instruments, while at the same time a warning sign appeared, bearing in large black letters the word:

DANGER!