A circumstance which seemed to render the expedition in a great measure hopeless, was the ease with which the English could maintain a constant watch upon their operations within the port of Boulogne. The least appearance of stir or preparation, to embark troops, or get ready for sea, was promptly sent by signal to the English coast, and the numerous British cruisers were instantly on the alert to attend their motions. Nelson had, in fact, during the last war, declared the sailing of a hostile armament from Boulogne to be a most forlorn undertaking, on account of cross tides and other disadvantages, together with the certainty of the flotilla being lost if there were the least wind west-north-west. "As for rowing," he adds, "that is impossible.--It is perfectly right to be prepared for a mad government," continued this most incontestible judge of maritime possibilities; "but with the active force which has been given me, I may pronounce it almost impracticable." Buonaparte himself continued to the last to affirm that he was serious in his attempts to invade Great Britain, and that the scheme was very practicable. He did not, however, latterly, talk of forcing his way by means of armed small craft and gun-boats, while the naval forces on each side were in their present degree of comparative strength, the allowed risk of miscarriage being as ten to one to that of success;--this bravade, which he had uttered to Lord Whitworth, involved too much uncertainty to be really acted upon. At times, long after, he talked slightingly to his attendants of the causes which prevented his accomplishing his project of invasion;[39] but when speaking seriously and in detail, he shows plainly that his sole hope of effecting the invasion was by assembling such a fleet as should give him the temporary command of the Channel. This fleet was to consist of fifty vessels, which, despatched from the various ports of France and Spain, were to rendezvous at Martinico, and, returning from thence to the British Channel, protect the flotilla, upon which were to embark one hundred and fifty thousand men.[40] Napoleon was disappointed in his combinations respecting the shipping; for as it happened, Admiral Cornwallis lay before Brest; Pellew observed the harbours of Spain; Nelson watched Toulon and Genoa; and it would have been necessary for the French and Spanish navy to fight their way through these impediments, in order to form a union at Martinico.