s retreat forced Tourville to leave behind him unfought the
squadrons of Shovel and Killigrew, and so far as commanding a line of
invasion passage was concerned Tourville was himself as well contained as
Torrington. The conditions of naval defence against invasion are in fact so
complex compared with those of general naval defence that they must be
treated later as a special branch of the subject.

The doctrine of the "Fleet in being" as formulated and practised by
Torrington and developed by Kempenfelt goes no further than this, that
where the enemy regards the general command of a sea area as necessary to
his offensive purposes, you may be able to prevent his gaining such command
by using your fleet defensively, refusing what Nelson called a regular
battle, and seizing every opportunity for a counterstroke. To use it as it
was used by the French in the case of Tourville's famous deterrent cruise,
where the whole object of the French was offensive and could not be
obtained except by offence, is quite another thing.

It is indeed difficult to understand the admiration with which his
_campagne au large_ has been treated in France. He kept the sea off the
mouth of the Channel for fifty days in the summer of 1691, and for forty of
those days our Channel fleet was making no systematic effort to seek him
out. He had been sent to sea in hope of intercepting our great "Smyrna
convoy," which was then the backbone of our oversea trade. Russell with the
British main fleet simply took positions to cover its approach until it was
safe, knowing presumably that Tourville must come to him if he wished to
accomplish his purpose. When the convoy was safe Russell proceeded off
Ushant, that is, between the enemy and his base. Tourville's communications
were thus cut, his line of retreat threatened, and he seized the first
opportunity to elude Russell and to return into port. Beyond taking a few
ships from one of the West India convoys, he accomplished nothing. The
central French offensive in Ireland was broken at the battle of the Boyne,
and the prestige of England at sea was restored. It is true our trade
suffered in the North Sea, but this was not directly due to the
concentration which Tourville's cruise forced upon us, but rather to the
failure of the Dutch--apparently by a misunderstanding-to provide for an
effective blockade of Dunkirk.

To British eyes it will seem that the heresy which was latent in
Tourville's instructions was a