, this
gangway happened to be rigged exactly over the ash port, which was thus
quite effectually concealed from the view of even the most prying eyes.
And there undoubtedly were several pairs of eyes very curiously and
intently watching everything that was happening aboard the English
yacht, not the least intent among them being those of the custom-house
officer, who planted himself upon the bridge of the _Thetis_, fully
determined that nothing great or small should be passed from the yacht
to the coal hulk without his full knowledge and consent. Thus, thanks
to the exceeding care with which Milsom had made his dispositions,
Jack--who, with the two Montijos, was supposed to be down below--and
Macintyre, fully equipped in their diving dresses, and with their tools
slung to their belts, had not the slightest difficulty in leaving the
yacht unobserved, and descending to the bottom of the harbour by way of
a diving ladder.

The water being shallow and tolerably clear, and the sun high enough in
the heavens to throw a strong light down into it, the two adventurers
were able to see well enough to be able to pass from the yacht to the
torpedo boat without any other guide than that of their unaided
eyesight; and within ten minutes the pair found themselves beneath the
bottom of their quarry, the keel of which was, as Jack had anticipated,
within about three feet of the ground. The boat, they found, was driven
by a single propeller protected by a skeleton frame forming the boat's
keel and sternpost, and to climb into this frame occupied Macintyre less
than a minute, helped as he was by Jack. Macintyre's first act was to
subject the propeller nut to a very careful examination, after which he
fixed a big spanner in position and threw his whole weight upon it,
assisted by Jack, who was pulling at a rope attached to the extreme end
of the spanner handle. The nut, however, was rusted on so effectually
as to be immovable, so Macintyre climbed down and, by means of a slate
and a piece of chalk, consulted Jack as to what was best to be done to
overcome the difficulty. Looking up, and studying the structure of the
boat's stern intently, Jack saw that by steadying themselves by the
rudder chains they could both climb up and stand upon the arm of the
spanner, when, by bracing their shoulders against the boat's overhanging
stern, they could bring the whole of their united strength to bear, and
thus possibly start the nut. By means of