1) by the
Geneva Society for the Construction of Physical Instruments. The vessel
is 20.25 m. in length at the water line, has an everywhere equal width
of 3.9 m., and a length of 16 m. from the stern to the apex of the
parabola of the keel. The bottom of the boat is nearly absolutely flat.
The keel, which is 30 centimeters in width, contains the shaft of the
screw. The boiler, which is designed for running at twelve atmospheres,
furnishes steam to a two cylinder engine, which may be run at will,
either the two cylinders separately, or as a _compound_ engine. The
bronze screw is 1.3 m. in diameter, and has a pitch of 2.5 m. The vessel
has two rudders, one in front for slight speeds, and the other at the
stern. At rest, the total displacement is 52,300 kilogrammes.
This weight far exceeds what was first expected, by reason of the
superthickness given the iron plates of the vertical sides, of the
supplementary cross bracing, and of the superposition of the netting
necessary to resist the flexion of the whole. On another hand,
the tractive stress of the screw, which should reach about 4,000
kilogrammes, has never been able to exceed 1,800, because of the
numerous imperfections in the engine.
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