Far different was the procedure of the French. Carnot determined to retake Lyons and Toulon, even if the efforts against Spain and Sardinia had to be relaxed. Further, on the 16th of September there arrived at the Republican army west of Toulon the incarnation of warlike energy and skill. At the bidding of the Commissioners of the Convention, Napoleon Bonaparte had come from the arsenal at Marseilles to assist the few artillerymen then before Toulon. On the 17th he was placed in command of their insignificant siege artillery, and forthwith from the slopes two miles west of the town he opened fire on the nearest ships. It is incorrect to claim for him the origination of the plan of sinking the fleet by a fire from the height behind l'Eguilette; for three days earlier the Commissioners of the Convention had written that they would secure a position whence the allied fleet could be sunk by red-hot cannon-balls; and there was no point but the high ground behind Fort l'Eguilette which dominated both the inner and the outer harbours.[246] But it may freely be granted that Bonaparte clinched the arguments in favour of this course and brought to bear on it that masterful energy which assures triumph. It was the first occasion on which he crossed the path of Pitt; and here, as always, he had the advantage of a central position, and of wielding a compact and homogeneous force against discordant Allies.
The worst difficulty confronting the defenders of Toulon remains to be noted. There the Sea Power is at the mercy of the Land Power. To attempt to defend that city at the head of its land-locked harbour, dominated by promontories, was to court disaster unless the fleet had an army to protect it. In such a case a fleet is a source of danger rather than of safety. Its true function is to act where it can, either directly or indirectly, command the land. It operates with most effect against low and exposed coasts. St. Jean d'Acre affords, perhaps, the best example of a town at the mercy of a fleet. Portsmouth, Sydney, Brest, and Toulon cannot be held by an enemy unless he brings forces sufficient to hold the neighbouring heights. In occupying Toulon, the Sea Power was virtually putting its head into the lion's jaw. Only by degrees did the authorities at home understand this all-important fact. For some time it was veiled from Pitt; and, as we shall see, the Austrian Chancellor, Thugut, never did understand it. To those who were on the spot, the need of occupying the promontory behind l'Eguilette was apparent; and on 21st September Lord Mulgrave and Rear-Admiral Gravina led a force to seize the very height on which Bonaparte's will had already fastened. The Allies crowned it with a temporary work dignified by the name of Fort Mulgrave. The fortunes of Toulon turned on the possession of all the heights commanding the harbour, but especially of this one.