We must not leave our typical modern battleship without some reference to the way in which she is protected by armour. As in all such ships, the armour-plating is distributed (_a_) to protect her flotation and (_b_) to protect her guns. With the former object in view she has a broad water-line belt of the finest and strongest 13-1/2-inch armour procurable, which is supplemented by an armoured deck of considerable thickness. Each turret stands on a species of armoured tower, going right down to the armoured deck, and is itself made of 13-1/2-inch armour. Her flotation is further safeguarded by minute subdivision below the water-line. "Long experience of naval war has established a belief, shown by the practice of maritime powers to be unanimous, that a navy should comprise three great classes of ships, these classes admitting of much internal subdivision. In the period of the great naval wars there were ships of the line, frigates, and small craft. These are now represented by battleships, cruisers, and smaller and special-service vessels. Individuals of the first-mentioned class are intended to fight in large groups, that is to say, in fleet actions; those of the second class are intended for solitary service, or, at any rate, to fight only in small groups; while those of the third are intended, according to the subdivision to which they belong, for a variety of special purposes." So writes Admiral Sir Cyprian Bridge in his _Art of Naval Warfare_, and his definitions are clear and compact. With the battleship class we have already dealt, both as regards its evolution and present-day pitch of perfection; but want of space has precluded any attempt to trace the evolution of the cruiser in the same way. It is therefore necessary, before going on to describe the cruisers of our modern navy, to glance, in the briefest possible manner, at their predecessors of days gone by. Perhaps we may take the viking _skuta_, or fast scouting vessel, as its first prototype, scouting being one of the most important duties of a cruiser. Possibly the galleys and balingers of mediæval times may be regarded as the _skuta's_ successors, while the low-lying _Tiger_ and other ships of her class in Tudor reigns may be considered as the immediate precursors of the famous frigates and corvettes which figured so largely and did such yeoman service in our eighteenth- and early nineteenth-century maritime campaigns. Our first frigates were the _Satisfaction_, _Adventure_, _Nonsuch_, _Assurance_, and _Constant Warwick_, all built in the year 1646; and from that time up to about 1870 a constant succession of ships of this useful type were added to the navy, the latest ones being, of course, steam frigates.