boat between Liége and Seraing. The propeller of this consisted of a
strong centrifugal pump, with vertical axis, actuated by a low pressure
engine. This pump sucked water into a perforated channel at the bottom
of the boat, and forced it through a spiral pipe to the propelling
tubes. These latter consisted of two elbowed pipes issuing from the
sides of the vessel and capable of pivoting in the exhaust ports in such
a way as to each turn its mouth downward at will, backward or forward.
The water expelled by the elbowed pipes reacted through pressure, as in
the hydraulic tourniquet of cabinets of physics, and effected the
propulsion of the vessel. Upon turning the two mouths of the propelling
tubes backward, the boat was thrust forward, and, when they were turned
toward the front, she was thrust backward. When one was turned toward
the front and the other toward the stern, the boat swung around.
Finally, when the two mouths were placed vertically the boat remained
immovable. All the evolutions were easy, even without the help of the
rudder, and the ways in which the propelling tubes could be placed were
capable of being varied _ad infinitum_ by a system of levers.

The Seraing No. 2 had an engine of a nominal power of 40 horses, and
took on an average 30 minutes to make the trip, backward and forward, of
85 kilometers, with four stoppages.

The success obtained was perfect, and the running was most satisfactory.
It was remarked, only, that from the standpoint of effective duty it
would have been desirable to reduce the velocity of the water at its
exit from the propellers.

Mr. Poillon attributes the small effective performance to the system
employed for putting the water in motion. At time of Mr. Seraing's
experiments, only centrifugal force pumps were known, and the theoretic