It was perhaps the most critical period in our national history. On the heights above Boulogne lay Napoleon's Grand Army, 160,000 men, waiting for the French fleet to put to sea and secure its passage across the Straits of Dover.[85] The fate of England depended on the British Navy. There were twenty-one French line-of-battle ships in Brest, six others at Rochefort, and five sheltering in the Spanish port of Ferrol. At Brest, also, there were known to be upwards of 20,000 French soldiers; and another 20,000 under Augereau were under canvas at Rochefort, 'supposed against Ireland,' according to Admiral Cornwallis's instructions from the Admiralty. It was the business of the Channel Fleet to hold the enemy in check at all points from Ushant Island, off Brest, to Cape Finisterre, and prevent aid from elsewhere arriving to enable them to put to sea. At the same time, as his appointed part in the great strategic plan of campaign, Nelson off Toulon kept his tireless watch over the French Mediterranean Fleet. Thus the toils were set, the gambit was opened. 'They were dull, weary, eventless months,' says Captain Mahan in one of his most telling passages,[86] 'those months of watching and waiting of the big ships before the French arsenals. Purposeless they surely seemed to many, but they saved England. The world has never seen a more impressive demonstration of the influence of sea-power upon its history. Those far-distant storm-beaten ships, upon which the Grand Army never looked, stood between it and the dominion of the world.' It was Napoleon with all the resources of his Empire in its full vigour at his back, Napoleon at the zenith of his intellect and genius for war, Napoleon in the year before Austerlitz--baffled and held at arm's length by the British Navy. One has only to glance at the daily newspapers of 1804 to realise the superb self-confidence with which Great Britain braced herself to meet the threatening peril. The nation knew its strength and on what, under Providence, it relied; the nation knew it and the Navy knew it--as we too, after forgetting it for a time, have in these later years at length come again to recognise the vital root-fact of Great Britain's existence-- No track of men, no footsteps to and fro Lead to her gates. The path lies o'er the sea Invincible.