regarded as permanently imposing strict limitations on its employment. The large airship, even should it be found to be of greater military or naval importance than suggested in the present volume, is scarcely likely to be better situated, and suffers from the not inconsiderable disadvantage of requiring accommodation of an elaborate and expensive kind. Hence we see that the "command of the air" is, from a world standpoint, a local condition. It might conceivably be secured and asserted by a European Power over half the continent of Europe, or the whole of the south and east of the African continent might be dominated by air fleets having their bases in Egypt and other territory in British occupation. Even this, however, is looking a great way ahead. For the time being we may take it that the policy of any one of the Great Powers in time of peace will be to secure unquestioned supremacy within its own territorial limits, with such bases in the vicinity of its coast lines and frontiers as will suffice to ensure the respect of hostile aircraft in the event of an outbreak of war. When a state of war exists, the task of an air fleet will be to maintain its air supremacy at home, and to extend and carry the command of the air over land or water in support of the Army and Navy, wherever operating. Hence the Aeronautical Force is not to be considered as a new kind of Navy, or otherwise as a self-contained Service to which large-scale independent duties can be assigned; it is definitely, in the words of our title, a new or Fourth Arm.
§ 102. Neutral Aircraft. International Regulations. It has been believed from the earliest days of the modern aeronautical movement that the military, (and naval) uses of the flying-machine would prove to be one of the most important of its initial applications. This view has been more than justified, so much so
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