=Source.=--_The Times_, October 1.
The interest excited by the recent trials of the Nordenfeldt
submarine boat is sufficiently shown by the presence at Landskrona
of thirty-nine officers, representing every European Power,
together with Brazil and Japan. The Nordenfeldt boat, the first of
its class, was built at Stockholm about two years ago. The boat is
cigar-shaped, with a coffin-like projection on the top amidships,
formed by vertical combings supporting a glass dome or conning
tower, 1 foot high, which enables the commander to see his way.
The dome, with its iron protecting cover, stands on a horizontal
lid, which can be swung to one side to allow the crew of three men
to get in or out without difficulty. The length of the hull is
64 feet, and the central diameter 9 feet. It is built of Swedish
mild steel plates ⅝ inch thick at the centre, tapered to ⅜ inch
at the ends.... In order to prepare for action, enough sea-water
is taken in to reduce the buoyancy to 1 cwt., which suffices to
keep the conning tower well above the surface. In order to sink
the boat further, the vertical propellers are set in motion, and
by their action it is held at the required depth. Thus to come
to the surface again it is merely necessary to stop the vertical
propellers, in which case the reserve of buoyancy at once comes
into play.... The motive power is steam alone. For submarine work,
as stoking is, of course, impossible, the firebox has to be sealed.
It is therefore necessary to store the requisite power beforehand,
and this is done by heating the water in two tanks placed fore
and aft, till a pressure of about 150 pounds per square inch is
obtained. With about this initial pressure the boat has been driven
for sixteen miles at a speed of three knots.... No compressed
air is carried, and the crew depend therefore for existence on
the amount of air sealed up in the hull. With this amount of air
only, four men have remained for a period of six hours without any
special inconvenience.