‘The Admiral writes outside, “Good look-out and prompt action of _Swallow_ probably averted a casualty to the convoy.” He has to write that most days--he must be tired of writing it.’ It is now two minutes to seven. As we drop into our picket-boat, the destroyer slips silently from her moorings and fades away down stream with eleven other thin grey phantoms. CHAPTER V SUBMARINES AND WAR POLICY ‘Strategy,’ says the ‘Encyclopædia Britannica,’ ‘has been curtly described as the art of concentrating an effective fighting force at a given place at a given time, and tactics as the art of using it when there.’ In less scientific language, you fight a battle by means of tactics, and a campaign by means of strategy. But when nations live, as we have all been living for many years past, in constant preparation for war, there must be forethought as to the means and methods to be employed. Each nation has broad general plans, ready for the moment when fighting is decided upon, and ships, guns, and armies are provided accordingly. This is what is meant by war policy; and examples will come to mind at once. We live in a group of islands, with Dominions and other possessions overseas, and we have no desire to attack our continental neighbours. British war policy has therefore always been chiefly directed to the provision of an invincible navy for defending our shores and our commerce. The German Empire, on the other hand, is practically self-contained; it lies on the Continent, with land powers for neighbours whom it has long hoped and intended to dominate. German war policy, therefore, concerned itself until quite recently with plans for aggression by land, and only provided a powerful fleet when it became desirable to have a weapon in hand against England--not necessarily to fight us on equal terms, but, as they said themselves, to make us hesitate to take sides against them. In this way it came about that both countries had a great naval war policy, and watched each other carefully, building dreadnoughts against dreadnoughts, and cruisers against cruisers. We made great and successful efforts to keep the lead; for sea power is a matter of life and death to us; and the Germans were spending every mark they could spare, to get more and more nearly upon even terms. It is certain that the war policy of both Powers took account of the possible uses of submarine boats; but the lines of thought which they followed were in some ways widely different, and they led, when war came, to unexpected developments. Let us consider for a few moments what the British admirals on the one hand, and the German on the other, intended to do with their submarine forces, and what they actually did when the time for action came.