Torpedoes may be readily improvised from kegs or casks pitched outside. The fuze should be put in place before filling with powder, in order that it may be near the center of the charge. The spar leading-wires pass out through the close fitting scores in the bung. The latter, after being secured in its place, should be pitched over thoroughly, and weight added to the whole, in order that it may be readily immersed. For exercise torpedoes, bottles, oil-cans, etc., may be used. An excellent composition for rendering the bung and the entrance of the leading-wires water-tight is made by melting together 8 parts of pitch, 1 of beeswax and 1 of tallow. It is to be applied while fluid. In order to burn all of the powder in the torpedo, a spindle, to contain the fuze, should be made on board of wood, following the general form of spindle in a gunpowder torpedo, and using a wrapping of cotton cloth, bunting, or paper, to prevent the powder passing through the flame-holes and choking up the spindle. =Splicing on the Fuze.=—To splice the fuze to the spar leading-wires so arrange the length of wire that the fuze will be entered in the spindle, reaching well into the torpedo-case when the entrance for the wires is closed. The leading-wires must be stripped of covering exterior to the insulation, to a distance extending to just outside the entrance. At this point the outer wrapping on the wires should be secured by a good whipping. If the outer wrapping on the wire is admitted inside, it will, after a time, act so as to introduce water to the charge. To make the splices, strip the insulation from the leading-wires for about an inch, and brighten them. Brighten the fuze-legs and twist them around the leading-wires in a manner similar to that employed in the Service Torpedo, arranging the splices, however, so that they shall be at equal distances from the top of the fuze. Cut off extra ends and lay the splices in the scores of the fuze-plug; turn the insulator down over them, and secure it with the insulator fastener. (See sample splice in supply-box). USE OF THE PERMANENT WIRES AND ELECTRIC SWITCHES. =Connecting.= (_Plate IX._)—The connections with the firing-battery are as follows:—one wire from each switch is connected to one battery terminal, and the common-return wire, with the hand-firing key interposed, is connected to the other battery terminal. The connections with the firing-key of the A machine are as follows:—one wire from each switch is connected to one binding-post, marked T, of the firing-key, and the common-return wire is connected to the other binding-post of the firing-key, also marked T. When electric switches are used an intelligent and careful person must be stationed at each switch, the index of which must be kept pointing toward “Battery off; connection through,” except when it is desired to prepare the circuit for firing any torpedo, when the index must be turned so as to point toward the torpedo which is about to be fired.