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 receive a torpedo attack.”  Press keys 5, 3, 4, 8, and the lights of lamps 5, 3, 4, 8, successively blaze out.

Electrical launches have been used to some extent, their storage batteries being first charged ashore or on board the ship to which the launch belongs.  They have carried hundreds of people, and have made eight knots an hour.  The improvement of storage batteries, steadily going on, will eventually cause the electrical launch to replace the steam launch.  One of its advantages is in having no noise from an exhaust and no flame flaring above a smoke pipe to betray its presence.  In warfare two sets of storage batteries should be provided for launches, one being recharged while the other is in use.

Mr. Gastine Trouse has recently invented “an electric sight,” a filament of fine wire in a glass tube covered with metal on all sides save at the back.  The battery is said to be no larger than a man’s finger, and to be attached to the barrel near the muzzle by simple rubber bands, so arranged that the act of attaching the battery to the barrel automatically makes connection with the sight; and so arranged also that the liquid of the battery is out of action except when the musket is brought into a horizontal position for firing.

To throw a good light upon the target the same inventor has devised a small electric lamp and projector, which is placed on the barrel near the muzzle by rubber bands, the battery being held at the belt of the marksman, with such connections that the act of pressing the butt of the musket against the shoulder completes the circuit, and causes the bright cylinder of light to fall on the target, thus enabling him to get as good a shot as in the day time.

Search lights and incandescent lights are advantageously used with balloons.  In submarine boats electricity will one day be very useful.  Submarine diving will play a part in future wars, and the diver’s lamp will be electrical.

Progress has been made also in constructing “electrical guns,” in which the cartridge contains a fuse which is ignited by pressing an electric button on the gun.  A better aim can be had with it, when perfected, than with one fired by a trigger.  At present, according to Lieut.  Fiske, this invention has not reached the practical stage, and the necessity for a battery to fire a cartridge is decidedly an objection.  But the battery is very small, needs little care, and will last a long time.  The hard pull of the ordinary trigger causes a movement of the barrel except in the hands of the most highly skilled marksmen, and this hard pull is a necessity, because the hammer or bolt must have considerable mass