"Therefore we have but to decide what the calibre for each class of ships should be, a decision which should present no special difficulty, provided it be first determined how we are to defeat the enemy--whether by the destruction of his ships (by sinking them or disabling their guns) or by the destruction or demoralization of their personnel. "In this connection the following facts should first be clearly understood--namely: "1. Turrets are now, for the first time, being designed that are practically invulnerable to all except heavy projectiles. Instead of having sighting-hoods on the turret roof, where sights, pointers, and officers are exposed to disablement (as frequently happened in the Russian ships) there will be prismatic sights, projecting laterally from the gun trunnions, through small holes in the side of the turret, and the gun-ports will be protected by 8-inch armour plates, so arranged that no fragments of shells can enter the turrets. "2. On the proposed all-big-gun ships the heavy armour belt will be about eight feet above the water-line, and extending from end to end. The conning-tower, barbettes, etc., will be of heavy armour; and there being no intermediate battery (which could not be protected by heavy armour, on account of its extent), it follows that in battle all the gunnery personnel, except the small, single fire-control party aloft, will be behind heavy armour, and that, therefore, neither the ship or her personnel can be materially injured by small calibre guns. "Considering, therefore, that our object in designing a battleship is that she may be able to meet those of our possible enemies upon at least equal terms, it seems evident that it would be extremely unwise to equip our new ships with a large number of small guns that are incapable of inflicting material damage upon the all-big-gun one-calibre ships of our enemies, or upon the personnel manning their guns." In the same paper Commander Sims explained the principal tactical qualities that are desirable in a fleet--namely, compactness of the battle formation and the flexibility of the fleet as a unit--that is, its ability to change its formation in the least possible time and space with safety to its units. Proceeding to elaborate his views, Commander Sims stated: "For example, suppose two fleets of eight vessels each, composed of ships that are alike in all respects, and suppose their personnel to be equally skilful, with the exception of the Commanders-in-Chief, whose difference in energy and ability is such that one fleet has been so drilled as to be able to manoeuvre with precision and safety while maintaining one-half the distance between its units that the other fleet requires. "This is putting an extreme case, but it shows: