to those
found in the general signal-book, in which are printed all the words,
phrases, and sentences necessary to frame an order, make an inquiry,
indicate a geographical position, or signal a compass course. Answering,
interrogatory, preparatory, and geographical pennants form part of this
code; also telegraph, danger, despatch, and quarantine flags.

The signal, having been prepared, is hoisted and left flying until the
vessel to which the message has been sent signifies that it is understood
by hoisting what is called the answering pennant. If the number hoisted by
the flag-ship is a preparatory order for a fleet movement, it is left
flying until all the vessels of the fleet have answered, and then is
pulled down, the act of pulling the signal down being understood as the
command for the execution of the movement just communicated.

It is often necessary for a man-of-war to communicate with a merchant
vessel, or with some other war-ship belonging to a foreign country. For
this purpose the international code is also carried in the signal-chest.
These signals are those in general use by all the merchant navies of the
world for communication by day at sea. There are eighteen flags and a code
pennant, corresponding to the consonants of the alphabet, omitting x and
z. The code pennant is also used with these signals.

If a message is to be sent at night, the Ardois system of night signals,
with which all our vessels carrying an electric plant are fitted, is
employed. These signals consist essentially of five groups of double
lamps, the two lamps in each group containing incandescent electric lamps,
and showing white and red respectively. By the combination of these lights
letters can be formed, and so, letter by letter, a word, and hence an
order, can be spelled out for the guidance of the ships of the squadron.
These lamps are suspended on a stay in the rigging, and are worked by a
keyboard from the upper bridge.

On the smaller ships of the service, those which are not fitted with
electric lighting, Very's night signals are used. This set includes the
implements for firing and recharging the signals.

The latter show green and red stars on being projected from pistols made
for them. The combination in various ways is used to express the numbers
from one to nine and cipher, so that the numbers, to four digits,
contained in the signal-book, may be displayed. The Myer wigwag system is
employed either by day or by nigh