only by a concurrence of successful evasions, of which the failure of any one nullified the result. Linked together as the various British fleets were by chains of smaller vessels, chance alone could secure Bonaparte’s great combination, which depended upon the covert concentration of several detachments upon a point practically within the enemy’s lines. Thus, while bodily present before Brest, Rochefort, and Toulon, strategically the British squadrons lay in the Straits of Dover barring the way against the Army of Invasion. The Straits themselves, of course, were not without their own special protection. Both they and their approaches, in the broadest sense of the term, from the Texel to the Channel Islands, were patrolled by numerous frigates and smaller vessels, from one hundred to a hundred and fifty in all. These not only watched diligently all that happened in the hostile harbors and sought to impede the movements of the flat-boats, but also kept touch with and maintained communication between the detachments of ships-of-the-line. Of the latter, five off the Texel watched the Dutch navy, while others were anchored off points of the English coast with reference to probable movements of the enemy. Lord St. Vincent, whose ideas on naval strategy were clear and sound, though he did not use the technical terms of the art, discerned and provided against the very purpose entertained by Bonaparte, of a concentration before Boulogne by ships drawn from the Atlantic and Mediterranean. The best security, the most advantageous strategic positions, were doubtless those before the enemy’s ports; and never in the history of blockades has there been excelled, if ever equalled, the close locking of Brest by Admiral Cornwallis, both winter and summer, between the outbreak of war and the battle of Trafalgar. It excited not only the admiration but the wonder of contemporaries.[73] In case, however, the French at Brest got out, so the prime minister of the day informed the speaker of the House, Cornwallis’s rendezvous was off the Lizard (due north of Brest), so as to go for _Ireland, or follow the French up Channel_, if they took either direction. _Should the French run for the Downs_, the five sail of the line at Spithead would also follow them; and Lord Keith (in the Downs) would in addition to his six, and six block ships, have also the North Sea fleet at his command.[74] Thus provision was made, in case of danger, for the outlying detachments to fall back on the strategic center, gradually accumulating strength, till they formed a body of from twenty-five to thirty heavy and disciplined ships-of-the-line, sufficient to meet all probable contingencies.