[Illustration:  FIG. 6.—­ROSSI’S TREMITOSCOPE.]

Rossi’s Tremitoscope.—­This instrument (Fig. 6) unites, upon the same stone base, three different arrangements for showing evidences of trepidations of the earth.  On one side we find (protected by a glass tube) a weight suspended over a mercury cup by a spring, and designed to show vertical motions.  The two other parts of the apparatus are designed for registering horizontal motions.  The first is a pendulum which causes a contact with four distinct springs, and whose movements are watched with a spy-glass.  The second is a steel spring which carries at its upper part a heavy ball that vibrates at the least shock.  This ball is provided with a point which is movable within a second ball, so that its motion produces a contact.  All these different contacts are signaled or registered electrically.

[Illustration:  FIG. 7.—­SCATENI’S SEISMOGRAPH.]

Scateni’s Registering Seismograph.—­This apparatus, which is shown in Figs. 7 and 8, consists of two parts—­of a transmitter and of a registering device.

[Illustration:  FIG. 8.—­REGISTERING APPARATUS.]

The transmitter consists of a glass vessel supported upon a steel point and provided beneath with a platinum circle connected with a pile.  All around this circle are four strips of platinum, against one of which abuts the circle at every movement of the glass.  Each strip of platinum communicates, through a special wire, with one of the electro-magnets of the registering device (Fig. 8).  This latter consists of an ordinary clock that carries three concentric dials—­one for minutes, one for hours, and one for seconds.  In a direction with the radii of these dials there are four superposed levers, each of which is actuated by one of the electros.  On another hand, each dial is divided into four zones that correspond to the four cardinal points.  When a shock coming from the north, for example, produces a contact, the corresponding electro is affected, and its lever falls and marks upon each of the dials a point in its north zone.  We thus obtain the exact hour of the shock, as well as its direction.  As may be seen, the apparatus, as regards principle, is one of the simplest of its kind.—­La Lumiere Electrique.

* * * * *

NEW ACCUMULATORS.

[Illustration:  FIG. 1.—­ARNOULD & TAMINE’S ACCUMULATOR.]

In Messrs. Arnould and Tamine’s accumulators, shown in Fig. 1, the formation is effected directly by the current, as in the Plante pile, but the plates are formed of wires connected horizontally at their extremities by soldering.  These plates are held apart either by setting them into paraffined wooden grooves at the ends of the trough or by interposing between them pieces of paraffined wood.

[Illustration:  FIG. 2.—­BARRIER & TOURVIELLE’S ELECTRODOCK.]