the enemy's
tubes. All torpedo-boat destroyers carry torpedo tubes themselves, so that
they can be used against the enemy's battle-ships or cruisers if the
occasion offers. The fastest boat in the United States navy is the
destroyer _Bailey_, which can steam thirty-four miles an hour.

In a naval battle the success or failure of a fleet may depend on keeping
open communication between the different vessels of the squadron engaged.
Owing to the fact that the surface of the sea would often be obscured by
the smoke of battle, the difficulty of this is apparent, and naval experts
have been kept busy devising some method by which the flag-ship can
communicate with the other vessels of the squadron at all times and under
all conditions. So far nothing has been put in general service which meets
this demand, but lately there have been experiments with the telephone,
which, it is said, can be used without wires, by which signals can be
projected by a vibrator on one vessel against a receiver on another. The
Navy Department is keeping the details of this new system carefully to
itself, as it desires to have the invention for the exclusive use of our
own ships of battle.

The present method of communication is by the use of flags representing
numerals which are displayed in the rigging; by the use of the Ardois
system of lights for night work; by the Myer code of wigwag signals, and
by the use of the heliograph. As it is of the utmost importance that the
enemy should not read the message, the signal books on board a vessel are
protected with the greatest care, and are destroyed along with the cipher
code whenever it is seen that capture is inevitable. The semaphore system
in use in the British navy was tried for a time aboard some of our
vessels, but it never became popular, and has been abandoned.

In signalling by the navy code, the sentence to be sent is looked up in
the code-book and its corresponding number is obtained. This number is
never more than four figures, on account of the necessity of setting the
signal with the least delay. The number having been obtained, the
quartermaster in charge of the signal-chest proceeds to bend the flags
representing the numerals to the signal halliards, so as to read from the
top down. These flags represent the numerals from one to nine and cipher,
and there is a triangular pennant termed a repeater, which is used in a
combination where one or more numerals recur. The numbers refer