tle, just as fast as the air can leak
out through the little leaks all around."

"I thought you stopped all the leaks," said Nathan.

"Yes," replied Jonas, "I stopped all the real leaks, but still I can't
make it perfectly tight. Some air can escape between the leather and the
nails all around, and just as fast as it can get out, so fast you can
press the sides together, and no faster."

Here Nathan tried again with all his strength; but he could only bring
the sides together very slowly.

"Now comes the second experiment," said Jonas. "While Nathan is trying
to press the two handles together, you, Rollo, may run your finger into
the hole, and push up the valve a little."

Rollo did so. He pushed up the valve a little with his finger, and that
allowed the air to escape through the opening. The consequence was, that
the bellows collapsed at once under the pressure which Nathan was
exerting upon them.

"There," said Jonas, "you see that when the air is kept in, you cannot
bring the sides together; but when I let the air out, then they come
together easily."

"Yes," said Nathan; "do it again, Rollo."

So they performed the experiment again. Nathan pulled the handles apart
wide, while Rollo kept his thumb over the nose, to keep the air from
issuing through. Then Nathan tried to press them together; but he could
not, until Rollo put his finger under, and pushed up the valve a little,
and then they came together again very easily.

"The air is a real thing, I verily believe," said Nathan.

"Yes," said Rollo, "I know it is. And now for the third experiment,
Jonas."

"The third experiment," said Jonas, "is this. Turn the bellows bottom
upwards, and try to blow."

Nathan did so. He found that he could work the bellows easily--too
easily, in fact; but they did not blow.

"Hold your hand opposite the nose, and see if any wind comes," said
Jonas.

They did so; there was no wind, or rather scarcely any.

"The reason is," said Jonas, "that, when the bellows are bottom upwards,
the valve hangs down off from the hole all the time, and lets the air
all out through the hole in the side; and it can come out more easily
there than through the nose, and so it don't blow well."

"Well, Jonas," said Rollo, "that's a pretty good experiment; but what is
the next? Let me try the next. Nathan, it is my turn."

"The next experiment, which is the fifth,----"

"No, the fourth," said Nathan.

"The fourth, then," said Jonas, "