its initiation as a commercial air route is begun. The French, for instance, hope to push a trunk air route to India via Constantinople, and this line has the advantage of avoiding a long sea and desert crossing. On the other hand, it will be a very difficult matter to negotiate the mountains of Anatolia. If enterprises of this kind are successfully started, if each of our self-governing Dominions and Colonies encourages civil aviation within its own territory, and develops the air-sense of its people, each portion of the Empire, by a process of natural expansion, and by the gradual extension of local air lines to merge with those from other portions of the Empire, will assist in eventually forming a continuous chain of inter-Imperial air communication. Such a process of internal development, supported by close co-operation between the States of the Imperial Commonwealth, is the best method of obtaining rapidity of air intercommunication and a system of Imperial air bases necessary to the strategic security of the Empire. CONCLUSION Within the necessarily narrow limits of this survey there has been traced the history of aviation from the earliest days; the tremendous impetus given to it by the war has been described, during the course of which not only did air co-operation become essential to the Navy and Army, but the importance of the Air Force as a separate arm, with its own strategic action, steadily grew; the increasing preponderance which aerial warfare will have in the future, and the horrors which it may bring, have been touched upon; and the possibilities of civil aviation in peace and war have been outlined. The conclusion has been reached that we cannot dispense with aviation, even if we would. We must consider it as a whole and lay down the broad principles on which it should be developed. The air (I write as one who during the last months of the war held the post of Chief of the Air Staff) materially helped, if it did not actually win, the fight. It has greatly complicated and increased the problems of defence. In future its influence on these problems will be still greater. The air has no boundaries. Great Britain and the Empire are no longer protected by the seas. A correct assessment of their needs will entail a growing ratio of air force to Army and Navy, and air power will in itself depend on the development of civil aviation. But though air action may be expected with justice to grow in proportion to that of the Army and Navy, and will certainly absorb certain functions of both, it would be unwise, at this early stage of development, for air forces to attempt too much at a time--such as, for instance, to garrison geographically unsuitable countries.