oned gallantry up the gangway, the others following.

As well as the party could discern in the obscurity, they now found
themselves standing in an apartment some ten feet square by seven feet
in height, with no other perceptible means of egress from it than the
trap-door by which they had entered; but upon the professor stretching
forth his arm and groping for a moment about the wall, the room became
suddenly illumined by the radiance of an electric light set in a very
thick and strong glass globe let into the ceiling, and it now became
apparent that there was a door in the bulkhead opposite them as they
entered.

"This small room," said the professor, "is known as the chamber of
egress, because, as is quite obvious, it is from here that one leaves
the ship for the outer world. But it has also another purpose besides
the mere furnishing of access to the trap-door, as I will endeavour to
explain to your ladyship. You are, of course, aware that one of the
objects with which the _Flying Fish_ was constructed was to enable her
crew to explore the ocean depths, and to examine and, if necessary,
operate upon the ocean's bed. Now, in order to leave the ship and walk
out upon the sea floor, an aperture of some kind in the hull is clearly
necessary, through which we may pass; and that aperture you see before
you in the shape of the trap-door. But you will readily understand
that, with the ship sunk to the bottom, the water will pour violently
through that trap, if it is opened without the observance of proper
precautions; and unless some special means are adopted to prevent such a
catastrophe, the water will quickly invade and fill the entire hull.
Hence this room. Its use, in actual practice, is this: having donned
our diving-suits in the diving-room, we pass into this small chamber by
means of the door of communication, which you see in that partition,
close the door carefully behind us, and turn on this tap, which admits a
small stream of water into the room from outside. The pressure of water
being considerable, the room quickly fills; but the partition, with its
water-tight door, effectually prevents the water from penetrating any
farther into the hull of the ship--and we then throw open the trap-door,
and walk forth on to the sea floor. Upon our return we close the
trap-door behind us, thus, turn on this air tap, and immediately a
stream of densely compressed air rushes into the chamber, expelling the
water throug