with the outward air.

At first the onlookers were amused; then they became interested, and as
the minutes flew by, a little anxious, but Maxwell's grave countenance,
as seen through the bull's-eye, gave no cause for alarm. Thus he stood
for full ten minutes, and then opening the escape-valve, signalled for
more air.

This was a sufficient evidence that a man might have ample time to
return to the surface from great depths, even if the air-pumps should
break down.

"But, perhaps," said Edgar, as they conversed on the subject, "you might
not be able to hold out so long under water where the pressure would be
great."

"Sure that's true. What d'ee say to try, David?" said Rooney.

Again Maxwell expressed willingness to risk the attempt. The glass was
once more screwed on, the pumps set agoing, and down the bold diver went
to the bottom. On receiving a pre-arranged signal, the pumps were
stopped.

This, let the reader fully understand, is a thing that is never done
with the ordinary pumps, which are not permitted to cease working from
the time the bull's-eye is fixed on until after it is taken off, on the
diver's return to the surface. It was therefore with much anxiety that
the experimenters awaited the result--anxiety that was not allayed by
Rooney Machowl's expression of countenance, and his occasional
suggestion that "he must be dead by this time," or, "Och! He's gone
entirely now!"

For full five minutes Maxwell stayed under water without a fresh supply
of air--then he signalled for it, and the anxious pumpers sent it down
with a will. Thus it was found that there was still sufficient time for
a man to return to the surface with the air contained in his dress, in
the event of accident to the pumps. [See Note 1.]

While the divers were engaged with these experiments, Chok-foo was sent
on shore in the small boat for a supply of fresh water from a spring
near the top of the island.

Having filled his keg, the Chinaman turned his fat good-humoured
countenance toward the sea, for the purpose of taking an amiable view of
Nature in general before commencing the descent. As he afterwards gazed
in the direction of the mainland, he observed what appeared to be a line
of sea-gulls on the horizon. He looked intently at these after
shouldering his water-keg. Chok-foo's visage was yellow by nature. It
suddenly became pale green. He dropped his burden and bounded down the
hillside as if he had gone mad. The