In the first place, the oscillating bronze cylinder, A, is cast in one
piece with the distribution cock, _a_, Fig. 3, and its seat, _b_, also
of bronze, is adjusted and fastened by means of the screw, _b_, to the
air reservoir, C', cast with its cistern, C, acting as foundation or
bed plate for the motor. This cistern is held either on the base of
the cast iron bearing frame, D, of the main shaft, _d_, _d_, Figs. 1
and 2, or directly on the sewing machine table, Figs. 3 and 4, by
means of two pins, _e_ and _e'_, so that it can oscillate about an
axis which is perpendicular to the shaft, _d_, to which is attached
the disk, F, carrying the crank.

This arrangement of parts, in combination with the horizontal axis of
the distribution valve and with the piston rod, _g_, considered as a
vertical axis of rotation, forms a species of universal joint between
the crank pin and the table, so that it can be put in place without
adjustment by any workman, who only has to screw up the two screws,
_h_, to fasten to the table the standard, E, and the piece, E', in
which are screwed the pivots, _e_ and _e'_, which support the tank,
and this all the rest of the motor.

As is seen more clearly in Fig. 2, the water under pressure enters by
the pipe, _c_, to which is attached a small tube of India rubber, and
leaves by the pipe, _c'_, and is carried away by another India rubber
tube.

The openings of the distribution cock are symmetrically pierced in the
seat and plug, which latter is divided internally by a horizontal
diaphragm so arranged that at each oscillation communication is
established alternately above and below the piston. So that it can be
started or stopped quickly, the opening and closing of the throttle