tions are made quickly and correctly,
that no lines are tied up unnecessarily, that messages are properly
charged to the right persons, that in case of a break in a line the
messages are switched round the trouble, and above all that there shall
be no delay.

When you take your receiver off the hook a tiny electric bulb glows
opposite the brass-lined hole that is marked with your number on the
switchboard of your central, and the telephone girl knows that you are
ready to send in a call--the flash of the little light is a signal to
her that you want to be connected with some other subscriber. Whereupon,
she inserts in your connection a brass plug to which a flexible wire is
attached, and then opens a little lever which connects her with your
circuit. Then she speaks into a kind of inverted horn which projects
from a transmitter that hangs round her neck and asks: "Number, please?"
You answer with the number, which she hears through the receiver
strapped to her head and ear. After repeating the number the "hello"
girl proceeds to make the connection. If the number required is in the
same section of the city she simply reaches for the hole or connection
which corresponds with it, with another brass plug, the twin of the one
that is already inserted in your connection, and touches the brass
lining with the plug. All the connections to each central station are so
arranged and duplicated that they are within the reach of each operator.
If the line is already "busy" a slight buzz is heard, not only by
"central," but by the subscriber also if he listens; "central" notifies
and then disconnects you. If the line is clear the twin plug is thrust
into the opening, and at the same time "central" presses a button, which
either rings a bell or causes a drop to fall in the private exchange
station of the party you wish to talk to. The moment the new connection
is made and the party you wish to talk to takes off the receiver from
his hook, a second light glows beside yours, and continues to glow as
long as the receiver remains off. The two little lamps are a signal to
"central" that the connection is properly made and she can then attend
to some other call. When your conversation is finished and your
receivers are hung up the little lights go out. That signals "central"
again, and she withdraws the plug from both holes and pushes another
button, which connects with a meter made like a bicycle cyclometer. This
little instrument records