different circuits must be arranged for different parts of the ship, and
the wires carrying the current must be arranged in duplicate. It is also
easy to repair a break in a copper wire if shot away. As to the dynamo
and engines, they must be placed below the water line, under a protective
deck, and this should be provided for in building the vessel. There
should be several dynamos and engines. All the dynamos should, of course,
be of the same electromotive force, and feed into the same mains, from
which all lamps draw their supply, and which are fed by feeders from the
dynamo at different points, so that accident to the mains in one part of
the ship will affect that part only. But it is the arc light, used as
what is called a search light, that is most valuable in warfare. Lieut.
Fiske thinks its first use was by the French in the siege of Paris, to
discover the operations of the besiegers. It can be carried by an army in
the field, and used for examining unknown ground at night, searching for
wounded on the battle field, and so on. On fighting vessels the search
light is useful in disclosing the attack of torpedo boats or of hostile
ships, in bringing out clearly the target for guns, and in puzzling an
enemy by involving him successively in dazzling light and total darkness.
Lieut. Fiske suggests that this use would be equally effective in
embarrassing troops groping to the attack of a fort at night by sudden
alternations of blinding light and paralyzing darkness. There should be
four search lights on each side of a ship.

As to the power and beauty of the search light, Lieut. Fiske refers to
the magnificent one with which he lighted up Philadelphia last autumn,
during the electric exhibition in that city. One night he went to the
tower of the Pennsylvania railroad station and watched the light
stationed at the Exhibition building on 32d street. The ray of light when
turned at right angles to his direction looked like a silver arrow going
through the sky; and when turned on him, he could read the fine print of
a railroad time table at arm's length. Flashes from his search light were
seen at a distance of thirty miles.

In using incandescent lamps for night signaling, the simplest way is to
arrange a keyboard with keys marked with certain numbers, indicating the
number of lamps arranged in a prominent position, which will burn while
that key is being pressed. For example, suppose the number 5348 means
"Prepare to rec