Finally, there is the question of risk.  In the old days, before free movement and wireless telegraphy, and before the flotilla had acquired battle power, there was always to be faced the risk of not getting contact in time to prevent mischief.  This consideration was specially dominant where the enemy had a squadron within or near the critical theatre of operations.  Therefore when the invasion threatened, our developed policy was to blockade Brest closely at almost any sacrifice.  There was always a vague possibility that by evasion or chance of wind a squadron so close to the line of invasion might get sufficient temporary command in the vital area before it could be brought to action.  It was a possibility that was never realised in the Narrow Seas, and since mobility of fleets and means of distant communication have so greatly increased in range and certainty, and since the power of resistance in the flotilla has become so high, the risk is probably much less than ever, and the field for open blockade is consequently less restricted.

There is no need, however, to accept these principles as incontrovertible.  Even if we take the great blockade of 1803-5, which has most firmly dominated thought on the subject ever since, it may be argued with some plausibility that the situation could have been solved more quickly and effectually by letting Ganteaume get out from Brest into the open, at least as far as Admiral Togo was forced to permit the Russians to emerge from Port Arthur, though his reasons for keeping them in were even stronger than ours in 1805.  But in any case, the whole trend of the evidence will admit no doubt as to the inherent weakness of close blockade as a form of war.  As under modern developments the possibilities of open blockade have increased, so the difficulties and dangers of close blockade have certainly not decreased.  It is also probable that certain advantages which in the sailing era went far to compensate for its weakness have lost much of their force.  A sailing fleet cooped up in port not only rapidly lost its spirit, but, being barred from sea-training, could not be kept in a condition of efficiency, whereas the blockading fleet was quickly raised to the highest temper by the stress of vigilance and danger that was its incessant portion.  So long as the strain did not pass the limit of human endurance, it was all to the good.  In the old days, with very moderate reliefs, the limit was never reached, and the sacrifices that were made to those exhausting vigils were rewarded twentyfold in exuberant confidence on the day of battle.  Can we expect the same compensation now?  Will the balance of strength and weakness remain as it used to be?  In the face of the vast change of conditions and the thinness of experience, it is to general principles we must turn for the answer.