The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

MODERN CIRCUIT CLOSERS. 439
the needle is deflected to the right; then, by carrying the
ball to the right, the needle is deflected to the left; and when
the ball is brought to the vertical position, the needle is
vertical. These three changes enter into the plans of several
electric telegraphs, which are to be hereafter described.
MODERN CIRCUIT CLOSERS.
In later years, the mercury cups have been abandoned, and
metallic connectors are used in their stead. Fig. 18 represents
a circuit closer, that accompanies the keys represented by fig.
11. The base A is made of wood;
between A and c is a brass pin Fig. 18.
serving as a stop to the lever B. a
The lever moves around a fulcrum
at the centre; c c are the top A S- B
ends of the elongated screws,
D D, the lower ends of which are
attached to the circuit wires;
these screws pass through the
table board. The line wires
enter the holes as seen in the
larger ends of the screws, and
the binding screws E hold the
wires with a good metallic con- D
tact; F is a spring which causes
the lever to press upon the upper
ends of D D. This is the normal
position of the circuit closer. The
key is open and the current
passes from the wire into the |
long screw D at E, thence through
the lever from c to c, thence down
to the line wire. If the operator E E
desires to manipulate with his
key, it is necessary to move the lever B from c, to the pin
by which the circuit is broken, and then upon pressing the
lever of the key, the circuit is again closed. Whenever the
operator has finished manipulating, it is necessary to close the
circuit by placing the lever arm of fig. 18 in its present position.
Figs. 19, 20, 21, and 22, are circuit closers of different forms,
but constructed upon the same principle as fig. 18.
Like arrangements are used for the transference of circuits
from one apparatus to another. There are a variety of arrangements for effecting this end. Figs. 23 and 24 are in common