of great-ships increased with the ripening of seamanship and naval architecture, the fireship as a battle weapon became almost negligible, while a fleet at anchor was found to be thoroughly defensible by its own picket-boats. Towards the middle of the eighteenth century indeed the occasions on which the fireship could be used for its special purpose was regarded as highly exceptional, and though the type was retained till the end of the century, its normal functions differed not at all from those of the rest of the flotilla of which it then formed part.
Those functions, as we have seen, expressed the cruising idea in its purest sense. It was numbers and mobility that determined flotilla types rather than armament or capacity for sea-endurance. Their primary purpose was to control communications in home and colonial waters against weakly armed privateers. The type which these duties determined fitted them adequately for the secondary purpose of inshore and despatch work with a fleet. It was, moreover, on the ubiquity which their numbers gave them, and on their power of dealing with unarmed or lightly armed vessels, that we relied for our first line of defence against invasion. These latter duties were of course exceptional, and the Navy List did not carry as a rule sufficient numbers for the purpose. But a special value of the class was that it was capable of rapid and almost indefinite expansion from the mercantile marine. Anything that could carry a gun had its use, and during the period of the Napoleonic threat the defence flotilla rose all told to considerably over a thousand units.
Formidable and effective as was a flotilla of this type for the ends it was designed to serve, it obviously in no way affected the security of a battle-fleet. But so soon as the flotilla acquired battle power the whole situation was changed, and the old principles of cruiser design and distribution were torn to shreds. The battle-fleet became a more imperfect organism than ever. Formerly it was only its offensive power
that required supplementing. The new condition meant that unaided it could no longer ensure its own defence. It now required screening, not only from observation, but also from flotilla attack. The theoretical weakness of an arrested offensive received a practical and concrete illustration to a degree that war had scarcely ever known. Our most dearly cherished strategical traditions were shaken to the bottom. The "proper place" for our battle-fleet had always been "on the enemy's coasts," and now that was precisely where the enemy would be best pleased to see it. What was to be done? So splendid a tradition could not lightly be laid aside, but the attempt to preserve it involved us still deeper in heresy. The vital, most difficult, and most absorbing problem has become not how to increase the power of a battle-fleet for attack, which is a comparatively simple matter, but how to defend it. As the offensive power of the flotilla developed, the problem pressed with an almost bewildering intensity. With every increase in the speed and sea-keeping power of torpedo craft, the problem of the screen grew more exacting. To keep the hostile flotilla out of night range the screen must be flung out wider and wider, and this meant more and more cruisers withdrawn from their primary function. And not only this. The screen must not only be far flung, but it must be made as far as possible impenetrable. In other words, its own power of resistance must be increased all along the line. Whole squadrons of armoured cruisers had to be attached to battle-fleets to support the weaker members of the screen. The crying need for this type of ship set up a rapid movement for increasing their fighting power, and with it fell with equal rapidity the economic possibility of giving the cruiser class its essential attribute of numbers.
As an inevitable result we find ourselves involved in an effort to restore to the flotilla some of its old cruiser capacity, by endowing it with gun armament, higher sea-keeping power, and facilities for distant communication, all at the
cost of specialisation and of greater economic strain. Still judged by past experience, some means of increasing numbers in the cruising types is essential, nor is it clear how it is possible to secure that essential in the ranks of the true cruiser. No point has been found at which it was possible to stop the tendency of this class of vessel to increase in size and cost, or to recall it to the strategical position it used to occupy. So insecure is the battle-squadron, so imperfect as a self-contained weapon has it become, that its need has overridden the old order of things, and the primary function of the cruising ship inclines to be no longer the exercise of control under cover of the battle-fleet. The battle-fleet now demands protection by the cruising ship, and what the battle-fleet needs is held to be the first necessity.
Judged by the old naval practice, it is an anomalous position to have reached. But the whole naval art has suffered a revolution beyond all previous experience, and it is possible the old practice is no longer a safe guide. Driven by the same necessities, every naval Power is following the same course. It may be right, it may be wrong; no one at least but the ignorant or hasty will venture to pass categorical judgment. The best we can do is to endeavour to realise the situation to which, in spite of all misgivings, we have been forced, and to determine its relations to the developments of the past.
It is undoubtedly a difficult task. As we have seen, there have prevailed in the constitution of fleets at various times several methods of expressing the necessities of naval war. The present system differs from them all. On the one hand, we have the fact that the latest developments of cruiser power have finally obliterated all logical distinction between cruisers and battleships, and we thus find ourselves hand in hand with the fleet constitution of the old Dutch
wars. On the other, however, we have armoured cruisers organised in squadrons and attached to battle-fleets not only for strategical purposes, but also with as yet undeveloped tactical functions in battle. Here we come close to the latest development of the sailing era, when "Advanced" or "Light" squadrons began to appear in the organisation of battle-fleets.
The system arose towards the end of the eighteenth century in the Mediterranean, where the conditions of control called for so wide a dispersal of cruisers and so great a number of them, that it was almost imperative for a battle-squadron in that sea to do much of its own scouting. It was certainly for this purpose that the fastest and lightest ships-of-the-line were formed into a separate unit, and the first designation it received was that of "Observation Squadron." It remained for Nelson to endeavour to endow it with a tactical function, but his idea was never realised either by himself or any of his successors.