Writing in 1905, Admiral Sir Reginald Custance exposed the whole tissue of fallacies on which the policy of building armoured cruisers had been based. The main duties of cruising ships are, first, to assist in winning and maintaining command of the sea, by acting as scouts and connecting links between the battle squadrons, and, secondly, to exercise command, once it has been established by the attack on and defence of trade. For the successful discharge of these functions the essential element is that the cruisers should be numerous. So long as their speed is equal, or superior, to that of the enemy cruisers, there is no reason why their individual strength should be greatly or at all superior. The armoured variety represents, roughly speaking, the value of three cruisers of ordinary type, and is manned by a crew almost proportionately larger. When first designed, it was possible to build these large cruisers of a speed superior to that of the smaller vessels, and having this monopoly, the French invented the type in pursuance of the idea that a sea war that consisted chiefly of attacks on commerce, promised brighter prospects than one which could not succeed unless based on battle-fleet supremacy. But this monopoly vanished nearly twenty years ago. For cruising purposes proper, then, this bastard type, while individually enormously more powerful than the light cruiser, was slower and so could not cover even one-third of the ground of its equivalent value in the smaller vessels. Over nine-tenths of the field of cruising, then, it represents a loss of between 60 and 70 per cent. of war efficiency, and this merely from its size.