efficiency have imparted to the English people, the return upon the investment has been beyond all calculation. The first and greatest lesson of the war, then, is this--that the value of an effective navy, when the time comes for it to manifest its effectiveness, is out of all proportion to the sums, vast though these may be, that it has cost; that if it overmatches the opposing navy decisively enough, the country behind it may rest secure and serenely indifferent to the thought of invasion or even of attack, so far as its sea frontier is concerned; and that the navy--still assuming it to be of commanding strength--may accomplish its whole mission of defense without ever being called upon to strike a blow. It can hardly be necessary to point out the fact that this lesson may be read in terms of "preparedness." The British navy was prepared when the war began; the British army was not. The German army was prepared; the German navy was not--in the sense of being large enough for its mission. With these facts in mind, we have only to look at the contrast between the progress of the war on land and that on the sea to read the whole lesson of preparedness in a form so concrete that it is hard to understand how any observer can fail to grasp its full significance. Among the minor lessons of the war, it will probably appear to most laymen that the unforeseen effectiveness of the submarine is the most significant. In a way this is true; but the significance of the lesson may be dangerously exaggerated unless we recognize the part contributed to the early successes of the submarine by the element of surprise to which allusion has already been made. When the war began, the submarine was an untried and an almost unknown weapon, and the British navy was rather contemptuous of it, or at least indifferent toward it. Its dramatic appearance in the North Sea at early dawn of a misty September morning was as great a surprise to the three British cruisers which it sank in rapid succession as the story of the disaster was to the world at large. The fact that the cruisers by their carelessness invited the fate which came to them does not, of course, deprive the incident of significance. But after all, the world has never doubted that a submarine could sink a ship that practically insisted upon being sunk. As a result of this experience, British men-of-war operating thereafter in what they considered submarine territory, took reasonable precautions; and in such waters no other important successes have been scored against them. But neither to them nor, probably, to anyone else except their adversaries, did it occur that a submarine could make its way from the North Sea to the Dardanelles. And so it came about that when one of them appeared there, it found conditions again ideal for surprise, and taking advantage of these conditions delivered its attack and scored a success as striking as the earlier one in its own home waters.