us, and during the invasion of France the telegraph played a
most important part. In military telegraph trains, miles of wire are
carried on reels in specially constructed wagons, which hold also
batteries and instruments. Some of the wire is insulated, so that it can
rest on the ground, and thus be laid out with great speed, while other
wire is bare, and is intended to be put on poles, trees, etc. For
mountain service the wires and implements are carried by pack animals.
Regularly trained men are employed, and are drilled in quickly running
lines, setting up temporary stations, etc. In the recent English
operations in Egypt, the advance guard always kept in telegraphic
communication with headquarters and with England, and after the battle of
Tel-el-Kebir news of the victory was telegraphed to the Queen and her
answer received in forty-five minutes.

The telephone is also used with success in warfare, and in fact sometimes
assists the telegraph in cases where, by reason of the haste with which a
line has been run, the current leaks off. A telephone may then be used to
receive the message--and for a transmitter a simple buzzer or automatic
circuit breaker, controlled by an ordinary key. In the case of vessels
there is much difficulty in using the telegraph and the telephone, as the
wire may be fouled and broken when the ship swings by a long chain. In
England in the case of a lightship this difficulty has been surmounted,
or rather avoided, by making hollow the cable by which the ship rides,
and running an insulated wire along the long tube thus formed inside. But
the problem is much simplified when temporary communication only is
desired between ships at anchor, between a ship and the shore, or even
between a ship and a boat which has been sent off on some special
service, such as reconnoitering, sounding, etc. In this case portable
telephones are used, in which the wire is so placed on a reel in circuit
with the telephone that communication is preserved, even while the wire
is running off the reel.

The telegraph and telephone are both coming largely into use in artillery
experiments, for example, in tracking a vessel as she comes up a channel
so that her exact position at each instant may be known, and in
determining the spot of fall of a projectile. In getting the time of
flight of projectiles electricity is of value; by breaking a wire in
circuit with a chronograph, the precise instant of start to within a
thousand