In order to realize what principles govern the use of navies, let us first consider what navies have to do and get history's data as to what navies in the past have done. It would obviously be impossible to recount here all the doings of navies. But neither is it necessary; for the reason that, throughout the long periods of time in which history records them, their activities have nearly always been the same. In all cases in which navies have been used for war there was the preliminary dispute, often long-continued, between two peoples or their rulers, and at last the decision of the dispute by force. In all cases the decision went to the side that could exert the most force at the critical times and places. The fact that the causes of war have been civil, and not military, demands consideration, for the reason that some people, confusing cause and effect, incline to the belief that armies and navies are the cause of war, and that they are to be blamed for its horrors. History clearly declares the contrary, and shows that the only rôle of armies and navies has been to wage wars, and, by waging, to finish them. It may be well here, in order to clear away a possible preconception by the reader, to try and dispel the illusion that army and navy officers are eager for war, in order that they may get promotion. This idea has been exploited by people opposed to the development of the army and navy, and has been received with so much credulity that it seriously handicaps the endeavors of officers to get an unbiassed hearing. But surely the foolishness of such an idea would promptly disappear from the brain of any one if he would remind himself that simply because a man joins the army or navy he does not cease to be a human being, with the same emotions of fear as other men, the same sensitiveness to pain, the same dread of death, and the same horror of leaving his family unsupported after his death. It is true that men in armies and navies are educated to dare death if need be; but the present writer has been through two wars, has been well acquainted with army and navy officers for forty-five years, and knows positively that, barring exceptions, they do not desire war at all. Without going into an obviously impossible discussion of all naval wars, it may be instructive to consider briefly the four naval wars in which the United States has engaged.