The four years of conflict have, however, afforded an opportunity for a further, and even more important, comparison. The problems of submarine war are not all material problems: moral qualities are needed to secure the efficient working of machinery, the handling of the ship under conditions of danger and difficulty hitherto unknown in war, and the conduct of a campaign with new legal and moral aspects of its own. In two of these departments, those of efficiency and seamanship, the Germans have achieved a considerable show of success, though it could be, and in time will be, easily shown that the British naval service has been more successful still. But in the domain of policy and of international morality, the comparison becomes no longer a comparison but a contrast; the new problems have been dealt with by the British in accordance with the old principles of law and humanity; by the Germans they have not been solved at all, the knot has simply been cut by the cruel steel of the pirate and the murderer. The methods of the U-boat campaign have not only brought successive defeats upon Germany, they will in the end cripple her commerce for many years; and, in addition to her material losses, she will suffer the bitter consequences of moral outlawry. Of the general efficiency of the German submarines it is too soon to speak, but it may be readily admitted that they have done well. We know, of course, many cases of failure--cases in which boats have been lost by defects in their engines, by running aground through mishandling in shoal waters, or by inability to free themselves from British nets. On the other hand, the German patrol has been kept up with a degree of continuity which, when we remember the dislocation caused by their severe losses, is, at least, a proof of determination. But the British submarine service has to its credit a record of work which, so far as can be judged from the evidence available, is not only better but has been performed under more difficult and dangerous circumstances. In the North Sea patrolling has been carried out regularly, in spite of minefields and of possible danger from the British squadrons, which must, of course, be avoided as carefully as if they were enemies. The German High Seas Fleet has been, for the most part, in hiding, but on the rare and brief occasions when their ships have ventured on one of their furtive raids British submarines have done their part, and the only two German Dreadnoughts which have risked themselves outside Kiel since their Jutland flight were both torpedoed on the same day. Better opportunities, as we shall see later, were found in the Baltic, where British submarines, in spite of German and Swedish nets, ice-fields, and the great distance of bases, succeeded in establishing a complete panic, by torpedoing a number of German war vessels and the cargo ships which they were intended to safeguard.