ercury. At this moment the oxidizing apparatus are put in
communication with an induction bobbin that is interposed in the circuit
of a dynamo, while through the tube, n, there is made to enter a mixture
of equal parts (in volume) of sulphurous acid, oxygen, and air. At the
same time, the cock of the tube, g, is opened, while the stirrer, T, is
set in motion. In this way we obtain, in a much shorter time than by
ordinary processes, a very liquid, transparent varnish, which, when
exposed to the air, quickly hardens. It is possible, with the same
process, to employ a mixture (in volumes) of two parts of protoxide of
nitrogen with one and a half parts of atmospheric air, or even protoxide
of nitrogen alone.

When it is judged that the operation is finished, the tube, g, is opened,
the stirrer is stopped, and the tube, c, is opened after d has been
closed. The steam then forces the varnish to pass through the tube, f,
and traverse the washing apparatus, which is filled half full of water,
that is slightly ammoniacal, and is heated by a circulation of steam, S.
Finally, the product, washed and free from every trace of acid is
collected upon making its exit from the tube, h.--_La Lumiere
Electrique._

* * * * *

NAGLO BROTHERS' TELEPHONE SYSTEM.

We borrow from the _Elektrotechnische Zeitung_ the following details in
regard to the telephonic installations made by the Brothers Naglo at
Berlin. Fig. 1 gives the general arrangement of a station, where J is an
inductor set in motion through a winch, K, and a pair of friction
rollers; W, a polarized call; U, an ordinary two-direction commutator; B,
a lightning protector; and L and T, the two terminals of the apparatus,
one of them connecting with the line and the other with the earth. The
interesting point of this system is the automatic communication which
occurs when the inductor, J, is moved. At the same moment that the winch,
K, is being moved, the disk, P, is carried from right to left and brought
into contact with the spring, f_{2}. As soon as the winch is left to
itself a counter-spring forces the disk, P, to return to a contact with
the spring, f_{1}. Figs. 2 and 3 show the details of such communication.
The winch, K, is keyed to one of the extremities of a sleeve that carries
the disk, P, at its other extremity. This sleeve is fixed upon the axle
of the first friction roller, that is to say, upon the axle that controls
the motion