electrical restoring drop employed by the Bell companies and
manufactured by the Western Electric Company. In this the coil _1_ is
a line coil, and it operates on the armature _2_ to raise the latch
lever _3_ in just the same manner as in the ordinary tubular drop.
The latch lever _3_ acts, however, to release another armature _4_
instead of a shutter. This armature _4_ is pivoted at its lower end at
the opposite end of the device from the armature _2_ and, by falling
outwardly when released, it serves to raise the light shutter _5_. The
restoring coil of this device is shown at _6_, and when energized it
attracts the armature _4_ so as to pull it back under the catch of the
latch lever _3_ and also so as to allow the shutter _5_ to fall into
its normal position. The method of closing the restoring circuit is by
placing coil _6_ in circuit with a local battery and with a pair of
contacts in the jack, which latter contacts are normally open but are
bridged across by the plug when it enters the jack, thus energizing
the restoring coil and restoring the shutter.

[Illustration: Fig. 262. Electrically Restored Drop]

A perspective view of this Western Electric electrical restoring drop
is shown in Fig. 263, a more complete mention being made of this
feature under the discussion of magneto multiple switchboards, wherein
it found its chief use. It is mentioned here to round out the methods
that have been employed for accomplishing the automatic restoration of
shutters by the insertion of the plug.

[Illustration: Fig. 263. Electrically Restored Drop]

Switchboard Plugs. A switchboard plug such as is commonly used in
simple magneto switchboards is shown in Fig. 264 and also in Fig. 235.
The tip contact is usually of brass and is connected to a slender
steel rod which runs through the center of the plug and terminates
near the rear end of the plug in a connector for the tip conductor of
the cord. This central core of steel is carefully insulated from the
outer shell of the plug by means of hard rubber bushings, the parts
being forced tightly together. The outer shell, of course, forms the
other conductor of the plug, called the sleeve contact. A handle of
tough fiber tubing is fitted over the rear end of the plug and this
also serves to close the opening formed by cutting away a portion of
the plug shell, thus exposing the connector for the tip conductor.

[Illustration: Fig. 264. Switchboard Plug]

_Cord Attachment._ Th