of hostilities. It is even probable that on the declaration of war all private aircraft will be requisitioned or impounded (as now done in the case of wireless telegraphic apparatus), and that neutrals will be advised that they will use the territorial air of the belligerent countries entirely at their own risk and peril; in fact, that they will be shot down if detected. We cannot for an instant admit a state of things such as would arise were neutral or private aircraft (with war correspondents and suchlike) allowed to fly in any area in which fighting might be in progress; there would be continual uncertainty as to the nationality of such alien aircraft, and no means of checking the abuse of a neutral flag by spies or imposters. The position is totally different from that which obtains at sea. There is no possible means of investigation, and no time to ask questions; if there is any doubt, instant action is imperative. It is only too evident that even if distinguishing marks were agreed, no reliance would be placed upon their genuineness in real warfare, and their disuse, sooner or later, may be considered to be a foregone conclusion.
It will be part of the business of the airmen and gunners of both belligerent armies to be fully conversant with the peculiarities of the various types of aircraft in their own service and in that of the enemy, and to be sufficiently "fly" to detect any attempts at disguise or deception. It is, of course, always open to the aircraft of either army to carry a distinguishing mark or sign which can be displayed at will, and the nature of this may either be known or unknown to the enemy; it may, to ensure secrecy, be changed from time to time like a "pass-word." This, however, is an entirely different matter to the compulsory wearing of a badge, like a uniform or a national flag, by which the nationality will be openly declared as a matter of obligation.
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