_I_ A movement to work the rudder while under water; on going to plunge the man who steers must take the helm off, this should always be his first act least he should forget it, _K_ The windlass of the plunging anchor sliding like that at the bow; _J_ The crank of the stern flyers; of the pumps, and of the plunging anchor; all these movements to be performed at pleasure by sliding the little wheels _N_ and _O_ in & our of gear; _P_ A screw movement to hoist the stern flyers out of gear; and out of water when the vessel is under sail, _M_ The pumps to force the water out at the pipe _R_. The mast descends the sail boom and mast are tied together and made fast to the deck before the operation of plunging commences. _Plate the Second one inch to a foot_, This exhibits a transeverse section _A_ the Valve to let in the the water which rises up to the deck _B.B_ from which to the upper deck all round the Vessel are chambers to hold submarine bombs; which are placed in the chambers through trap doors on deck; and which bombs being the weight of water will in plunging displace their volume of water; and not add to or deminish the weight of the Vessel; this is the best mode of arranging the bombs for were they inside they would be embarrassing and each one when taken out would require to be replaced with its weight of water— [Illustration: PLATE THE FIFTH ] [Illustration: PLATE THE SIXTH ] _F_ The pipe to give air, _G_ The pipe to discharge the Mephitic air, _H.H_ Two air pipes to let the air out of the water chambers; they mount to the highest part of the Vessel to let the air in when the water is discharging; there should be at least four of these pipes; two in the bow and two in the stern; they may be lead from the stem along side and unite at _I.I_ there the two mounting pipes _H.H_ will be suffecient, care must be taken that the air can pass off with ease from all parts of the water chambers, or they cannot fill, nor can the vessel be got under water, _C_ The balancing chamber. _D_ The safety pump _E_ The discharging pipe _J_ Is a valve to let the water go from the centre chamber to the two ends, but not return, by this means water may be drawn from either end to balance the Vessel horizontal there are four such Valves, All the communications with the exterior have cocks as will be seen in plate the third, _Plate the Third one inch to a foot_, Figure the first shews a section of the double forcing pumps _A_ and _B_ too cocks to draw the water from the right and left water chambers.