th an indicator like the ones just described.
It is a simple clock to which a few special devices have been added.
Seismic clocks may be classed in two categories, according as they are
stopped by the effect of a shock or are set running at the very instant
one occurs. The Messrs. Brassart have always given preference to those of
the second category, because there is no need of watching them during a
seismic calm, and because they are much more easily constructed. It is to
this class, then, that their seismic clock belongs. It is capable of being
used for domestic purposes in place of any other clock, and of becoming a
seismoscopic clock as soon as it is put in electric communication with the
seismic telltales.

To the cross-piece that holds the axle of the drums the inventors have
added (Fig. 5) a support formed of a strip of brass, S, with whose
extremity is jointed (at the lower part) a double lever, A. This latter is
held in a horizontal position by a small counterpoise, _i_, so that the
finger at the opposite extremity shall prevent the pendulum, P, from
swinging. To keep the latter in a position of rest a bent lever, _n n'_,
is jointed to the upper part of the support, S. The longer arm, _n'_, of
this lever is bent forward at right angles, so that it may come into
contact with and repel the small rod of the pendulum as soon as the lever
has been lifted by means of a small cord which is connected with the
larger arm, _n_, and runs up to a small hook, from whence it descends and
makes its exit under the clock-case.

In order to stop the clock, then, it is only necessary to pull on this
cord slightly, when, by moving the pendulum to the left, it will thrust
it against the inclined plane of the finger of the lever arm, A. It is
clear that the extremity of the pendulum, upon striking against the
finger, will depress it slightly and go beyond the projection against
which it remains fixed owing to the counterpoise, _i_. The fever, _n n'_,
is brought back to its position of rest by means of a small counterpoise
at the extremity of the arm, _n_. When the lever, A, is depressed, the
pendulum escapes and sets the clock running. This depression is effected
by means of an electro-magnet, E, whose armature, which is connected with
the rod, _t, t_, lifts the arm, _i_, of the lever, and depresses A. The
wires of the two bobbins of the electro-magnet end in two clamps, 1 and 2.
The second of these latter is insulated from the cloc