Within this adjustment chamber is also placed an automatic balance, which also assists to maintain the torpedo at the desired depth, by reason of its swinging forward on the torpedo descending, and swinging aft on its rising, which motion is used to regulate the horizontal rudders. The above is merely a general idea of the arrangement used in the Whitehead fish torpedo, to enable it to reach and maintain whatever depth it may be necessary to use it at from 5 to 15 feet. _Projecting the Torpedo._--The fish torpedo may be projected in various ways, viz.:-- 1.--Through a submerged tube in the stem, or on the broadside. 2.--From a carriage above the surface. 3.--From the surface. _Discharging Torpedo through a Submerged Tube in the Stem._--In this case a tube is fitted to an orifice in the stem; this opening is as far below the water line as possible, and is closed by a watertight cap and a sluice valve; the inner end of the tube is fitted with a watertight door; the torpedo being prepared for action is placed inside the tube, the inner door closed, and the tube filled with water; then the watertight cap and sluice valve are opened, and the torpedo started by means of a piston which is worked by compressed air. This piston can be worked from deck, and so the torpedo fired at the proper instant. To prevent the torpedo from slipping out of the tube, a stop is placed in the fore end of it, which can be withdrawn at the same time as the compressed air is admitted behind the piston. The torpedo being clear of the tube, the sluice valve and watertight cap are closed, and the tube emptied of the water, the projecting piston being at the same time forced back. _On the Broadside._--In this case, the discharging tube works inside an iron casing, through a stuffing box at the inner end, and in a shield attached to the outer end of the tube. This shield, placed on the fore side of the orifice, is of such a length as to protect the torpedo from the pressure of the water passing the vessel. The mode of discharging the torpedo in this case is similar to that used when projecting it through the stem. _Comparison of the Stem and Broadside Methods of Projecting the Torpedo._--The former method of projecting the torpedo seems the most suitable to specially built torpedo vessels, but not so to large ironclads, on account of the difficulty of fitting a tube to the stem of such a ship, and also that in so doing the efficiency of the vessel as a ram would be impaired. In regard to the accuracy of the firing of the above methods, both seem equally good, though in the case of firing on the broadside it would be necessary to prepare carefully calculated tables of deflection, any mistake in the using of which would be fatal to a successful torpedo shot.