do you think again? He began scraping in all the
conch-shells he could see that had what looked like a dab of mud or a
milky spot on the side.

He was after pearls!

Divers often fish for pearls midst oyster-beds, and in more shallow
water, but there are nets or dredgers also used for that purpose. But I
at once knew that very valuable pearls must often be found in
conch-shells and deep-sea oyster-shells, as the diver scraped in all of
both that he could find.

Remember! All kinds of shell-fish are called "mollusca," have white
blood, and breathe not only in the water, but also in the air.

And will you believe it? I have found out considerable about the signals
that a diver gives to the man at the pump on deck.

If he wants to be pulled up, be gives the life-line four sharp pulls.
If he wants more air, he gives one pull at the air-pipe. Two pulls on
the life-line, and two pulls on the air-pipe, given quickly one after
the other, mean that he is in trouble, and wants the help of another
diver. One pull on the life-line means "all right."

There are many other signals I could not find out the meaning of, so can
say nothing about. My instincts, as well as what I have noticed, tell me
that a diver must be in the best of health, must be rather thin, have
excellent eyesight, sound lungs, steady nerves, and a strong heart. The
work is not easy. I wonder if work that pays well is often easy? I do
not believe it is.

There used to be a strange machine in use called the "diving-bell." A
great cast-iron cage, shaped something like a bell, let down by ropes,
and so heavy that its own weight would sink it. Divers could sit inside,
and fresh air was supplied by a force-pump. Bull's-eyes of heavy glass
let in the light.

This must have frightened the fishes quite as much as did the diver,
although it was not as frightful in appearance.

After a time, when the diver came down, some of my mates, seeing I was
not a bit afraid if only hidden from sight myself, stayed near me under
the broad seaweeds, but most of them fled far and wide at his approach.

The divers themselves are not free from danger. Great sea-serpents or
sharks sometimes make it hot for them, but they are watchful, spry, and
being "Folks," with power to think and plan, can generally look out for
themselves and their safety.

CHAPTER VIII.

MY STRANGE ADVENTURE

Now come the most exciting and in some respects the hardest events of my
life thus far