The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

278 THE BRETT PRINTING TELEGRAPH.
and falls back upon the succeeding points, &c. A metallic
rod t,, fixed near the extremity La of the lever, communicates
with an hydraulic apparatus, called a g'overnor, the mechanism
of which I will presently describe. The object of the " governor" is to regulate the movement of the lever L1 L2, so that it
rises rapidly and descends slowly with a graduated velocity.
The arm of the lever Li Li bears a point or horizontal rod, p',
which glides over the eccentric E, placed on the axis a, and turning with that axis. The portion of the circumference of the
eccentric E, the farthest removed from the axis, is thicker, and
has two notches about a quarter of an inch apart, which
notches catch one after another of the points as p', so that the
eccentric stops in its rotation. Now, let the point p' rest upon
the portion of the eccentric nearest to the axis, the eccentric
which presents to it by turns the various points of the surface,
brings to it the first notch into which it falls, stopping the
movement of the eccentric. The point p' cannot get out, and
will not permit the eccentric to turn, except said point p' has
been raised with the lever L1 L2, by one of the points of the
type-wheel. After the raising of the point p, the eccentric has
turned again, and bringing to the point the second stop, the
movement stops a second time, and can only recommence when
the point following is disengaged from the stop, at the moment when the extremity Li of the arm of the lever shall leave
that of the points of the type-wheel which has raised it. The
point pl will then be upon the part of the eccentric nearest to
the axis. It is seen by this movement that the axis a is forced
to turn, when the type-wheel stops, and then by means of the
cranks brings the paper into contact with the letter or sign,
covered with the plumbago, which prints this letter or sign
upon the paper.
The hydraulic regulator or governor is formed, first, of a
glass vase v, fig. 6, filled with water, or
some other liquid; second, of an internal
vase, v, pierced with holes, through which
the liquid may pass, and terminating by
-Va - p la flange, upon which the upper part of the
apparatus is screwed. s is a pointed
metallic valve, rising from within outd 7'f id sward, p is a hollow piston, raised and
lowered by the rod t t moving in the chanm| be I ber c c' of the interior valve v', leaving
l o| V only a small circular space, through which;. the water ca.n pass. When the piston is
raised by the lever Li L25 fig. 3, to which the rod t is attached,