the flotilla has greatly increased.  Its real and moral effect against transports must certainly be greater than ever, and the power of squadrons to break a flotilla blockade is more restricted.  Mines, again, tell almost entirely in favour of defence, so much so indeed as to render a rapid coup de main against any important port almost an impossibility.  In the absence of all experience it is to such theoretical considerations we must turn for light.

Theoretically stated, the success of our old system of defence depended on four relations.  Firstly, there is the relation between the rapidity with which an invasion force could be mobilised and embarked, and the rapidity with which restlessness in foreign ports and places d’armes could be reported; that is to say, the chance of surprise and evasion are as the speed of preparation to the speed of intelligence.

Secondly, there is the relation of the speed of convoys to the speed of cruisers and flotilla; that is to say, our ability to get contact with a convoy after it has put to sea and before the expedition can be disembarked is as the speed of our cruisers and flotilla to the speed of the convoy.

Thirdly, there is the relation between the destructive power of modern cruisers and flotillas against a convoy unescorted or weakly escorted and the corresponding power in sailing days.

Fourthly, there is the relation between the speed of convoys and the speed of battle-squadrons, which is of importance where the enemy’s transports are likely to be strongly escorted.  On this relation depends the facility with which the battle-squadron covering our mobile defence can secure an interior position from which it may strike either the enemy’s battle-squadron if it moves or his convoy before it can complete its passage and effect the landing.

All these relations appear to have been modified by modern developments in favour of the defence.  In the first ratio, that of speed of mobilisation to speed of intelligence, it is obviously so.  Although military mobilisation may be still relatively as rapid as the mobilisation of fleets, yet intelligence has outstripped both.  This is true both for gaining and for conveying intelligence.  Preparations for oversea invasion were never easy to conceal, owing to the disturbance of the flow of shipping that they caused.  Elaborate precautions were taken to prevent commercial leakage of intelligence, but they never entirely succeeded.  Yet formerly, in the condition of comparative crudeness with which international trade was then organised, concealment was relatively easy, at least for a time.  But the ever-growing sensitiveness of world-wide commerce, when market movements are reported from hour to hour instead of from week to week, has greatly increased the difficulty.  And apart from the rapidity with which information may be gathered through this alert and intimate sympathy between Exchanges, there is the still more important fact that with wireless the speed of conveying naval intelligence has increased in a far higher ratio than the speed of sea transit.