150 feet, which is often done, what must the
pressure be there?"

"Tightish, no doubt," said Rooney.

"True, lad," continued Joe. "Of course, to counteract this we must
force more air down to you the deeper you go, so that the pressure
inside of you may be a little more than the pressure outside, in order
to force the foul air out of the dress through the escape-valve; and
what between the one an' the other your sensations are peculiar, you may
be sure.--But come, young man, don't be alarmed. We'll not send you
down very deep at first. If some divers go down as deep as twenty-five
fathoms, surely you'll not be frightened to try two and a half."

Whatever Rooney's feelings might have been, the judicious allusion to
the possibility of his being frightened was sufficient to call forth the
emphatic assertion that he was ready to go down two thousand fathoms if
they had ropes long enough and weights heavy enough to sink him!

While the recruit is preparing for his subaqueous experiments, you and
I, reader, will go see what Maxwell is about at the bottom of the sea.

CHAPTER TWO.

DESCRIBES A FIRST VISIT TO THE BOTTOM OF THE SEA.

When the diver received the encouraging pat on the head, as already
related, he descended the ladder to its lowest round. Here, being a few
feet below the surface, the buoyancy of the water relieved him of much
of the oppression caused by the great weights with which he was loaded.
He was in a semi-floating condition, hence the ladder, being no longer
necessary, was made to terminate at that point. He let go his hold of
it and sank gently to the bottom, regulating his pace by a rope which
descended from the foot of the ladder to the mud, on which in a few
seconds his leaden soles softly rested. A continuous stream of
air-bubbles from the safety-valve behind the helmet indicated to those
above that the pumps were doing their duty, and at the same time hid the
diver entirely from their sight.

Meanwhile the two men who acted as signalman and assistant stood near
the head of the ladder, the first holding the life-line, the assistant
the coil of air-tubing. Their duty was to stand by and pay out or haul
in tubing and line according as the diver's movements and necessities
should require. They were to attend also to his signals--some of which
were transmitted by the line and some by the air-tube. These signals
vary among divers. With Baldwin and his party one pull on the
_life-line