In Search of a Son

by William S. Walsh

"Of course," cried Miette, "it is the coin which opened the way. The paper was preserved by the coin from the resistance of the air."

"Exactly so," said Monsieur Roger; "and these simple experiments have led scientists to ask if in doing away entirely with the resistance of the air it would not be possible to abolish the differences which may be observed between the falling of various bodies,—for instance, the paper and the coin, a hair and a bit of lead. And they have decided that in a vacuum—that is to say, when the resistance of the air is abolished—the paper and the coin, the hair and the lead would fall with exactly the same swiftness; all of them would traverse the same space in the same time."

"The hair falls as fast as lead," said Miette, in a tone which seemed to imply, "I would like to see that."

Monsieur Roger understood the thought of Miette, and answered by saying,—

"Well, I am going to show you that."

He chose a long tube of glass, closed by bits of metal, one of which had a stop-cock. He put in this tube the coin, the round bit of paper, a bit of lead, and a strand of hair from Miss Miette's head. Then he fastened the tube by one of its ends upon the disk of the air-pump and worked the pistons. As soon as he thought that the vacuum had been made, he closed the stop-cock of the tube, to prevent the exterior air from entering. He withdrew the tube from the machine, held it vertically, then turned it briskly upsidedown. Everybody saw that the paper, the coin, the hair, and the lead all arrived at the same time at the bottom of the tube. The experiment was conclusive. Then Monsieur Roger opened the stop-cock and allowed the air to enter into the tube. Again he turned the tube upsidedown: the coin and the bit of lead arrived almost together at the bottom of the tube, but the paper, and especially the strand of hair, found much difficulty on the way and arrived at the bottom much later.

"Why, how amusing that is!" cried Miette; "as amusing as anything I know. I don't understand why Paul wishes to have nothing to do with physical science."

But Miette was mistaken this time, for Paul was now very anxious to learn more.

"Very well," said Monsieur Roger, "as all this has not wearied you, I am, in order to end to-day, going to make another experiment which will not be a bit tiresome, and which, without any scientific apparatus, without any air-pump, will demonstrate to you for the last time the existence of the pressure, of the weight of the atmosphere."