westward, because in that case he could hang upon Tourville's rear and flanks and take any opportunity that offered to get past him and concentrate the British forces to the westward of him. But Tourville gave him no such opportunity. He pressed him hard and might have pressed him back even to the Gunfleet if Torrington had not been ordered by Mary and her advisers to give battle "upon any advantage of the wind." But even in fighting the battle, which his own judgment told him ought not to be fought, he never lost sight of the paramount necessity of so fighting it as to give Tourville no decisive advantage. The victory was a barren one to Tourville. It gave him no command of the sea and for that reason he was unable to prosecute any enterprise of invasion. The command of the sea remained in dispute, and unless the dispute could be decided in Tourville's favour he would have fought and won the battle of Beachy Head in vain, as the event showed that he did. Torrington held that his "fleet in being," even after the reverse at Beachy Head, was a sufficient bar to the further enterprises of Tourville, nor can Tourville's subsequent action be explained on any other hypothesis than that he shared Torrington's opinion and acted on it. The truth is, that the doctrine of the fleet in being, as understood and illustrated by Torrington, is in reality the counterpart and complement of the doctrine of the command of the sea as expounded above. "I consider," said the late Sir Geoffrey Hornby, a strategist and tactician of unrivalled authority in his time, "that I have command of the sea when I am able to tell my Government that they can move an expedition to any point without fear of interference from an enemy's fleet." This condition cannot be satisfied so long as the enemy has a fleet in being, that is a fleet strategically at large, not itself in command of the sea, but strong enough to deny that command to its adversary by strategic and tactical dispositions adapted to the circumstances of the case. Thus command of the sea and a fleet in being are mutually exclusive terms. So long as a hostile fleet is in being there is no command of the sea; so soon as the command of the sea is established there is no hostile fleet in being. Each of these propositions is the complement of the other.