Once more the root principles of war were urged on public notice. But it was already too late. Jutland, whether a victory, or something far less than a victory, had at any rate left the public in the comfortable assurance that the ability of the British Fleet was virtually unimpaired to preserve the flow of provisions, raw material, and manufactures into Allied harbours and to maintain our military communications. But soon after the third year of the war began, a change came over the scene. The highest level that the submarine campaign had reached in the past was regained, and then surpassed month by month. Gradually it came to be seen that the thing might become critical--and this though the campaign was not ruthless. Yet it was carried out on a larger scale and with bolder methods which the possession of a larger fleet of submarines made possible. The element of surprise in the thing was not that the Germans had renewed the attempt--for it was clear from the terms of surrender to America that they would renew it at their own time. The surprise was in its success. The public, still trusting to the attitude of mind induced by the critics and by the authorities in 1915, had taken it for granted that the two previous campaigns had stopped in December, 1915, and in March, 1916, because of the efficiency of our counter-measures. The revelation of the autumn of 1916 was that these counter-measures had failed. It was this that brought about the third naval crisis of the war. Once more the old wrong remedy was tried. The Government and the public had learned nothing from the revelation that we had gone to war on the doctrine that the Fleet _need_ not, and _ought_ not, to fight the enemy, and were apparently unconcerned at discovering that it _could_ not fight with success. And so, still not realizing the root cause of all our trouble, once more a remedy was sought by changing the chief naval adviser to the Government. But on this occasion it was not only the chief that was replaced, as had happened when Lord Fisher succeeded Prince Louis of Battenberg, and when Sir Henry Jackson succeeded Lord Fisher. When Admiral Jellicoe came to Whitehall several colleagues accompanied him from the Grand Fleet. There was nothing approaching to a complete change of personnel, but the infusion of new blood was considerable. But this notwithstanding, the menace from the submarine grew, when ruthlessness was adopted as a method, until the rate of loss by April had doubled, trebled, and quadrupled that of the previous year. All the world then saw that, with shipping vanishing at the rate of more than a million tons a month, the period during which the Allies could maintain the fight against the Central Powers must be strictly limited.