The shaft _B_ may be made to revolve by means of ropes _G_ and pulleys _H_ attached to the levers _A_, or by hydraulic or steam pressure, as may be found most convenient.
The torpedo case can be towed alongside the vessel if necessary without deranging the apparatus. The torpedo case is carried in the angles of the bent levers, and is stowed away so that neither it nor the suspending levers project at all beyond the hull of the vessel; also when lowered, the levers and suspending rods fold over one another so as to occupy very little space, and the torpedo is suspended close to the hull.
Also the torpedo during the operation of lowering as well as when in a firing position remains close to the side of the vessel, thereby obviating any risk or inconvenience from excessive leverage which would have a tendency to capsize the boat.
For especially built torpedo launches, the above mode of carrying and launching the fish torpedo is certainly the best yet devised.
_Woolwich Fish Torpedo._--In the Woolwich torpedo, the engines exert a force of nearly 60 indicated horses, and work up to 1000 revolutions per minute; the total weight of the torpedo fully charged (33 lbs. of gun-cotton) is about 500 lbs.
[Illustration: THORNICROFT'S BOAT APPARATUS FOR FISH TORPEDOES.
The Whitehead fish torpedo costs about 380_l._, while the Woolwich one costs only 300_l._
_The Lay Torpedo Boat._--Priority of invention of this torpedo was on the 13th of June, 1873, awarded by the Commissioners of Patents to Mr. John Louis Lay, several other persons having claimed the invention, among whom was Colonel Von Scheliha, an officer of the Russian army.
This locomotive torpedo, or more properly called torpedo boat, has been for several years adopted by the American government, during which time it has undergone a series of exhaustive experiments, which has proved it to be a most valuable and efficient weapon of offence and defence. Lately the Russian government have adopted it, and intend using it extensively in the defence of their harbours, &c.