A minority, no doubt, was uneasy and did inquire. But they found their path crossed by difficulties almost insuperable. The literature of sea-power was based entirely upon the history of the great sea wars of a dim past. Mahan, it is true, had so elucidated the broad doctrines of sea strategy that it seemed as if he who ran might read. But lucid and convincing as is his analysis, urbane and judicial as is his style, Mahan’s work could not make the bulk of his readers adepts in naval doctrine. The fact seems to be that the fabled mysteries of the sea make every truth concerning it elusive, difficult for any one but a sailor to grasp. The difficulties were hardly lessened by Mahan’s chief work having dealt completely with the past. The most important of the world’s sea wars may be said to begin with the Armada and to end in 1815. In these two and one quarter centuries the implements of naval warfare changed hardly at all. Broadly speaking, from the days of Howard of Effingham to those of Fulton and Watt, man used three-masted ships and muzzle-loading cannon. Hence the history of the Great Age deals very little with the technique of war. To the lay reader, therefore, the study of sea-power, based upon these ancient campaigns, seemed not only the pursuit of a subject vague and elusive in itself, but one that becomes doubly unreal through the successive revolutions of modern times. It was like studying the politics of an extinct community told in records of a dead language. The incendiary shell, armour to keep the shell out, steam that made ships completely dirigible in the sense that they could with great rapidity be turned to any chosen course, these alone had, by the middle of the last century, completely revolutionized the tactical employment of sea force. Steam, which made a ship easier to aim than a gun, gave birth to ramming; and naval thought was hypnotized by this fallacy for nearly two generations. By the end of the century the whole art had again been changed, first by the development of the monster cannon, and next, a far more important invention, the mountings that made first light, and then heavy, guns so flexible in use that they could be aimed in a moderate sea way. These and the invention of the fish torpedo and the high speed boat for carrying it--that in the twilight of dawn and eve would make it practically invisible--brought about fresh changes that altered not only the tactics of battle, but those of blockade and of many other naval operations.