to discuss the advantages and disadvantages of the system. If we are to
believe Mr. Enuma, the advantages are very numerous, to wit: (1) The
cables have no need of being of large size; (2) the intensity is the same
through the entire extent of the primary circuit, secondary one, etc.; (3)
the resistance is invariable in all portions of the line; (4) the
apparatus are independent of each other, and consequently there may be a
disturbance in one or several of them without the others suffering
therefrom; (5) either a strong or weak luminous intensity may be produced,
since, that depends only upon the size of the coil employed; (6) there is
no style of lamp that may not be used, since each lamp is mounted upon a
special circuit; (7) any number of lamps may be lighted or extinguished
without the others being influenced thereby; (8) when a fire or other
accident happens in a house, it in no wise interferes with the service in
the rest of the line; (9) the system could, were it required, be connected
with any other kind of existing line; and (10) the cost of installation is
infinitely less than that of a system of gas pipes embracing the same
extent of ground.--_La Lumiere Electrique._

* * * * *

ELECTRICITY APPLIED TO THE STUDY OF SEISMIC MOVEMENTS.

Italy, with her volcanic nature, has very naturally made a specialty of
movements of the ground, or seismic perturbations. So the larger part of
the apparatus designed for such study are due to Italians. Several of
these instruments have already been, described in this journal, and on the
present occasion we shall make known a few others that will serve to give
an idea of the methods employed.

For the observation of the vertical and horizontal motions of the ground,
different apparatus are required. The following is a description of those
constructed for each of such purposes by the Brassart Brothers.

[Illustration: FIG. 1.--APPARATUS FOR THE STUDY OF HORIZONTAL SEISMIC
MOVEMENTS.]

_Apparatus for Studying Horizontal Movements._--A lever, (Fig. 1), movable
about a horizontal axis, carries a corrugated funnel, _i_, at one of its
extremities. At the other extremity it is provided with a counterpoise
which permits of its being exactly balanced, while not interfering with
its sensitiveness.

[Illustration: FIGS. 2 AND 3.--DETAILS OF THE APPARATUS.]

The opening of the funnel passes freely around a column, _v_ (Fig. 2),
upon which is p