about 6 inches square, had been punctured in the
skin, which until then had been kept tight by the rock that had caused
it. It was necessary to close this leak at once. An iron bolt, which was
screwed for a nut at one end, was obtained and passed through a strong
piece of wood about 2 feet square. The inside of this board was
cushioned with canvas and oakum, and it was taken down outside the ship
by the diver and placed over the hole, with the feathered end of the
bolt sticking through the hole; the diver was then sent down inside the
hold, and with a nut set up the whole cushion until the flow of water
was stopped. The leak was thus stopped which had threatened the
arrangements for floating the ship with failure.

It has been seen that the method of raising the Ulunda was very simple.
She was floated off by the rising tide. If there had been only a small
instead of an 18 foot rise, some other mode would have to have been
adopted. No attempt was made to stop any of the leaks, except the one
just stated, but a deck above the lacerations was made water-tight, and
this, together with the sides of the ship hanging down, formed a kind of
diving bell, the pressure of air in which, caused by the water outside,
acting on this deck, being the principal means of buoying up the ship,
assisted by the buoyancy of the two water-tight compartments. The deck
afterward built was only necessary for the safety of the ship, she being
able to float without it; but it would have been suicidal to trust the
ship on the Atlantic in the state she was in when raised, since with any
swell on, the compressed air would escape and its place be taken by
water, the buoyancy necessary for keeping her afloat being thus lost.

It only remains to be said that the risks run in steaming around to
Halifax by herself were, as it was, very great, and had the wind and sea
been less favorable, the undertaking would probably have proved a
disastrous failure.

* * * * *

THE THERMIC MOTOR OF THE FUTURE?

Up to recent years there was no reason for putting the question that
forms the title of this article, for it was admitted by all that the
conversion of thermic energy, or heat produced by the combustion of
coal, into mechanical energy or work could no longer be effected
economically except by having recourse to steam. In ordinary language,
and even to manufacturers, steam engine was the equivalent of thermic
motor, and it