hich nature puts in play in fishes and mollusks,
and the mode that we now wish to make known is without contradiction
that which imitates these the best.

Hydraulic propulsion by reaction consists, in principle, in effecting a
movement of boats, by sucking in water at the bow and forcing it out at
the stern. This is a very old idea. Naturalists cite whole families of
mollusks that move about in this way with great rapidity. It is probable
that such was the origin of the first idea of this mode of operating.
However this may be, as long ago as 1661 a patent was taken out in
England, on this principle, by Toogood & Hayes. After this we find the
patents of Allen (1729) and Rumsay (1788). In France, Daniel Bernouilli
presented to the Academic des Sciences a similar project during the last
century.

Mr. Seydell was the first to build a vessel on this principle. This
ship, which was called the Enterprise, was of 100 tons burden, and was
constructed at Edinburgh for marine fishery. The success of this was
incomplete, but it was sufficient to show all the advantage that could
be got from the idea. Another boat, the Albert, was built at Stettin,
after the same type and at about the same epoch; and the question was
considered of placing a reaction propeller upon the Great Eastern.

About 1860 the question was taken up again by the house of Cokerill de
Seraing, which built the Seraing No. 2, that did service as an excursion
boat between Liege 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