effective duty of these, whatever be the peculiar system of
construction, cannot exceed 66 per cent., and, in practice, falls to 40
or 50 per cent. in the majority of cases.

It is probable, then, that in making use of those new rotary pumps where
effective duty reaches and often exceeds 80 per cent., we might obtain
much better results, and it is this that justifies the new researches
that have been undertaken by Messrs. Maginot & Pinette, whose first
experiments we are about to make known.

In order to have it understood what interest attaches to these
researches, let us state the principal advantages that this mode of
propulsion will have over the helix and paddle wheel: The width of
side-wheel boats will be reduced by from 20 to 30 per cent., and the
draught of water will be diminished in screw steamers to that of the
hull itself; the maneuver in which the power of the engine might be
directly employed will be simplified; a machine will be had of a
sensibly constant speed, and without change in its running; the
production of waves capable of injuring the banks of canals will be
avoided; the propeller will be capable of being utilized as a bilge
pump; all vibration will be suppressed; the boat will be able to run at
any speed under good conditions, while the helix works well only when
the speed of the vessel corresponds to its pitch; it will be possible to
put the propelling apparatus under water; and, finally, it will be
possible to run the pump directly by the shaft of the high speed engine,
without intermediate gearing, which is something that would prove a very
great advantage in the case of electric pleasure boats actuated by piles
and accumulators and dynamo-electric machines.

[Illustration: NEW STEAMER PROPELLED BY HYDRAULIC REACTION.]