sed
inventions, during very rough and trying weather.

The swinging pendulum, with connected apparatus for compressing air
or, perhaps, for generating the electric current, seems to be the most
controllable and therefore the safest of the various types of
apparatus which are applicable to the utilisation of wave-power for
propulsion. In the construction of connecting machinery by which the
movements of a pendulum hanging up from a universal joint may be
transmitted to wheels or pistons operating compressors or dynamos, it
is necessary to transform all motions passing in any direction
through the spherical or bowl-shaped figure traced out by the end of
the pendulum in the course of its swinging. This may be effected, for
instance, in the case of a pendulum working air-compressors, by
mounting the latter on bearings like those of the gun-carriage in a
field piece, and having two of them operating one at right angles to
the other. The rods which carry the air-compressing pistons are then
connected to the end of the pendulum by universal joints, and the
parts which have been likened to a gun-carriage are fixed on pivots so
as to be able to move horizontally. Air-tight joints in the pipes
which lead to the compressed air reservoir are placed in the bearings
of this mounting. We thus have the same kind of provision for taking
advantage of a universal movement in space as is made in solid
geometry by three co-ordinates at right angles to one another for
measuring such movements.

Another plan is to have the pendulum swung in a strong steel collar
and carrying at its end three or more air-compressing pumps set
radially, with the piston-rods thrust outwards by a strong spring on
each, but with the ends perfectly free from any attachment, yet fitted
with a buffer or wheel. As the pendulum moves it throws one or more
of these piston-rod ends into contact with the inner surface of the
ring, driving it into the compressing pump. At the top of the pendulum
there is a double or universal pipe-joint through which the air under
pressure is driven to the reservoir, and by which the apparatus is
also hung. This is the simplest, and in some respects the best, form.

A very simple type of the wave-power motor as applied to marine
propulsion is based upon an idea taken from the mode of progression
adopted by certain crustaceans, namely the possession of the means for
drawing in and rapidly ejecting the water. Something of the kind will
m