The mention of the India-rubber tree, on a previous page, suggests the
application of the valuable substance derived from it, to one of its
many important uses, _viz._, to the _submarine_ or _diving armor_. This
is represented in the cut below, where the diver, or person about to
descend into the sea, is seen encased with a water-proof dress, made
chiefly of India rubber. His feet are heavily loaded with boots which
have soles made of thick plates of lead. On his head is a helmet-shaped
covering, made of iron, from which rises a hose, through which fresh air
is forced to him, by powerful air-pumps, when he is under the water.
This helmet, which is well padded, is furnished with two glass eyes,
which are protected by wire gratings. Around the waist is a strong
girdle provided with iron rings, one on each side, from which ascend
cords to the persons in the boat from which the diver descends, for the
purpose not only of aiding to guide him over the rocks, and helping him
to an upright position, but to serve for signalizing in case of sudden
danger or accident, and as a means of hauling him up when required. Thus
although the diver is at perfect liberty to direct his own movements, he
is still held in leading-strings from the boat, and all his motions are
vigilantly watched and cared for by his companions above. To aid him in
keeping under water, the diver also wears two heavy plates of lead, one
in front and the other behind, which are so adjusted as to leave his
arms at liberty, and at the same time give equilibrium to his submerged
body. In this case, he also has a bag in front, into which he may put
valuables of small size picked up in the deep, such, for example, as
pearls, or amber, both of which have been sought for by persons thus
equipped.
[Illustration: MANNER OF WORKING THE DIVING ARMOR.]
The method of exploring with this armor, is seen in the second cut,
where the diver is represented as below the water, while his companions
are in the boat above, some of them holding the ropes, some pumping down
air, and others holding the ladder, while the diver himself is picking
up some object of value from the bottom of the sea. This armor has been
used in searching for amber, pearls, lost treasure, &c., &c. And when,
some years since, the United States steam-frigate Missouri was sunk in
Gibraltar harbor, so as to obstruct navigation, and all attempts by
distinguished English engineers to raise her had proved in vain, an
American, going down in the above-described armor, explored her
position, and then contracted to blow her to pieces, which he
successfully accomplished, though she was in twenty-six feet water, and
covered by fifteen feet of sand. In doing this, he consumed forty-three
thousand pounds of powder, raised sixteen hundred tuns of iron, and some
eight hundred tuns of oysters that had grown to the iron. All his men
were clothed in the submarine armor, and so perfect was the management,
that not a life was lost, and not an accident happened during the whole
of the operation.
In this connection, the recently invented “Nautilus diving-bell” is
worthy of notice. This bell is provided with air-tight compartments,
which hold either air or water, as ascent or descent is required: and is
so ballasted that, when filled with water, buoyancy is destroyed, and
the machine gradually sinks. Expel the water from the tanks, and the
machine comes of course at once to the surface. By opening a valve near
the bottom of the bell, the water enters through a pipe into the tanks;
the air at the same time escaping through a valve at the top, opened or
closed by the operator at will. Descent is thus effected. On the
contrary, let air be turned into the tanks, escape at top be closed, and
valves at bottom opened, water is expelled and ascent secured. To raise
heavy weights, a greater or less amount of water is expelled.
Suspension-chains attached to weight, immediately tighten; machine and
weight become buoyant, and then by cables attached to anchors working
through stuffing-boxes, windlasses may be transported to any desired
spot, and there deposited. Free communication may be held with the
bottom through an opening of between twelve and fifty square feet,
according to size of bell, closed by an iron door, and secured by bolts.
By throwing the door back, an equilibrium between air and water may be
attained at any depth, by greater or less amounts of air, as determined
by suitable gauges permanently fastened in the bell. Such is the
ingenious mechanism of this wonderful contrivance.