Their object is to connect the firing-battery or the firing-key of the D. E. machine with any or all the torpedoes. The plate represents the switch in position, on the starboard side, with the battery off, or the wires from the firing-key disconnected from any permanent wire, electrically. The switch should be protected from salt water and the weather as much as possible. It is thought best to inclose it in a box, as nearly water-tight as possible, provided with a door which opens in front. =_Note._=—Where permanent firing apparatus is furnished, the electric switches will not be issued. TERMINALS. =Plate X.= Terminals are ordinary brass binding-screws secured to base-pieces of black walnut which are to be secured in position by screws. The figure illustrates the manner of making permanent and temporary connections with the terminals. The counter-sunk space in the back of the base-piece is to be filled with melted wax, after the permanent wire has been attached, before securing the terminal in place. The binding-screws must be kept clean and free from paint. ARTICLES OF TORPEDO OUTFIT SUPPLIED AT NAVY YARDS. =Ship‘s Spars.=—Such ship-rigged vessels as are now fitted for spar-torpedoes are supplied with four torpedo-spars, fitted two on each side, abreast the foremast and mizzenmast. Barque-rigged vessels are supplied with but two spars, fitted one abreast the foremast on each side. The present regulation spar is of hickory or oak, 45 feet long, 8 inches in diameter at the heel, and 6 inches at the outer end. It should be of the best material, straight-grained, and as nearly as possible a natural-growth pole. In working down a larger spar, care should be observed to follow the grain of the wood. Yellow oak is considered superior for torpedo-spars. Red oak is too brash. =The Heel Fittings.= (_Plate XI._)—The thrust-plate is placed at about the height of the channels, in accordance with the regulations established by the Bureau of Ordnance. Discretion must be used in so placing this as to allow the spar to come alongside, so that the torpedo can be shipped from the rail or from a port. The elbow of the heel-bolt transmits the recoil of the spar to the thrust-plate, without injury to the bolt itself. Good results have been obtained by using a lashing of 6 turns of 3½-inch manilla, in place of the shackle, the elasticity of the rope serving to take up a portion of the thrust of the spar. An excellent plan is to secure the heel of the spar to a spare eye-bolt in the channels, as shown in Fig. 2.