_Spar or Outrigger Torpedo._--By a spar or outrigger torpedo is meant a torpedo which is carried at the end of a pole or spar projecting from a boat or vessel, and which may be fired either by contact or at will. This system of submarine offence has up to the present time been the only one that has successfully stood the crucial test of actual warfare. During the civil war in America the spar torpedo attack was resorted to by the Confederates and Federals, principally by the former, the result being the loss of two large men of war and severe injury to several other ships composing the Federal fleet, and the loss of one vessel of war belonging to the Southerners. The spar torpedo was also used on several occasions by the Russians in their attacks on the Turkish ships in the war of 1877-8, but in only one attempt was it the means of sinking a Turkish vessel. _Description of McEvoy's Duplex Spar Torpedo._--At Fig. 142 is shown a sketch of Captain McEvoy's improved patent duplex spar torpedo, which is the form most generally used at the present time, and which seems to fulfil all the requirements of such a submarine weapon, viz.:-- 1.--Handiness, at the same time capable of containing a charge of gun-cotton sufficient in contact to destroy the most powerful vessel afloat. 2.--Certainty of action. 3.--Capable of being fired either on contact or at will. 4.--Mode of attaching the spar simple and very secure. [Illustration: LAY'S LOCOMOTIVE TORPEDO. PLATE XLIII] In Fig. 142, _a_ is the case, capable of containing some 33 lbs. of gun-cotton; _b_ is the tube through which the three wires _w_, _w_^{1}, and _w_^{2} are led; _c_ is the socket in which the wooden or steel spar is introduced and secured, _d_ is the striker, which is attached to a brass contact plate within the head of the case _a_ in such a manner that any pressure either on the head or side of the striker _d_ will force the aforesaid plate in contact with the two studs to which the battery wires are attached; _e_ is a cradle affixed to the striker _d_ to ensure its action on contact being made by the torpedo with the attacked vessel; the explosive is inserted at _f_, the socket _c_ being made to screw on and off. When a hollow steel spar is used, the battery wires are sometimes led through the interior of the torpedo and the spar, by which means they are well protected; the only objection to this method of leading the wires being the probability of injury to them, should the spar be broken on contact, or by a shot.