_The Lay Torpedo Boat used as a Tug to take out a Number of Small Torpedoes._--This arrangement is shown at Figs. 132 and 133. The small vessels or torpedoes are designed to be first sunk and then exploded, chiefly for clearing harbour or the like of mines or other obstructions. These results are accomplished by means of the following devices and arrangements, that is to say, each of the small vessels or torpedoes _F_ is provided with apparatus which is included in an electrical circuit formed by a suitable insulated cable _G_, extending throughout the train of small vessels or torpedoes _F_. One vessel of this train, preferably the rear one, is connected with the station by an electrical cable _H_, which is payed out from a coil or coils, or a reel or reels, in the said vessel as the same travels through the water. This cable _H_ connects with the cable _G_, which is connected with the towing boat _A_, and passes through the series of boats _F_ to the said cable _H_. One wire of the said cable is arranged in combination with sealed or covered apertures in the bottom of a compartment or compartments of these small vessels _F_, as shown at _I_, the covers of these apertures being so formed as to be ruptured or destroyed by the explosion of a cartridge or cartridges placed in the said compartment or compartments. When a current of electricity is sent through the aforesaid wire of the cable it will explode the said cartridges and open the apertures, thereby admitting water into the said compartments so that the vessel _F_ will sink. The cable _G_ that passes through the train of torpedoes or vessels _F_ is so arranged that when a current passes through the other wire of the said cable it will fire cartridges placed in the charge chambers or magazines of the said small vessels, as shown at _J_. The part of the cable or towing line _G_, which connects the towing boat _A_ with the train of small boats or torpedoes _F_, is attached to a hook or other device, which can be disengaged by sending a current through the cable _K_, connecting the boat _A_ with the shore or other station. It will be understood that when being used for this purpose the said boat _A_ is not or need not be charged with explosive material. [Illustration: LAY'S LOCOMOTIVE TORPEDO. PLATE XLI] The aforesaid towing boat _A_ takes the train of torpedoes _F_ to any required position. It is then disengaged from the train, leaving the said small vessels or torpedoes _F_ floating in such position. Then by sending a current first through one wire of the cable _H_ the boats _F_ are first sunk by the explosion of the cartridges and opening of the apertures, as above described. They may then be discharged immediately by sending a current through the other wire of said cable _H_ and firing the cartridges in their magazines, or they may be left submerged to form mines which may be exploded at any desired moment.