The increased war utility of aircraft has necessitated an extension of the pages devoted to organisation of military aviation, etc. The details given are by no means as full as I could wish; but all organisations are being so continually changed owing to increased experience that satisfactory data are not very easy to come by. During the past twelve months or so we have learned at least one or two important things. The mere fact of the possession of aeroplanes by a nation is a military factor of comparatively little importance. A nation possessing next to no aeroplanes can easily acquire a few hundreds in case of emergency _if she has the people to build them_. The real problem is two-fold. First, of course, is the possession of trained and efficient aviators to fly the machines. Naval and military officers who have merely secured their brevets at a flying school are of no immediate value; civilians of the same kind are of still less utility. Second to this is the productive capacity of any country; which may roughly be gauged from the number and importance of its firms engaged in construction. These points cannot too strongly be enforced. The air strength of any nation in case of war resides in its efficient flying men and in its own productive capacity. The next war will see aircraft quite as much "contraband" as warships, and the nation which relies upon aerial imports will be foredoomed at once. One month is probably the utmost effective life of an aeroplane on hard active service and it may well be a good deal less. And firms capable of building efficient machines cannot be improvised. A remarkable feature of the last twelve months has been the recrudescence of the dirigible, which is now in far greater esteem than it was a year ago, or for that matter, ever before. In the past there is no doubt that progress was hampered by arguments between the advocates of "heavier than air" and "lighter than air," and a curious notion that the one could only exist at the expense of the other. Such ideas are now dead, and it is recognised that for war purposes both have their uses and that both are interdependent. It is not quite yet realised how intense this interdependence is likely to be. Briefly the present situation may be summed up as follows: the dirigible has enormous potentialities for attack on fortified bases and the like, but its powers of defence, guns or no guns, are very slight. A single aeroplane should be able to disable or destroy without very great difficulty the finest dirigible yet built (supposing it able to find the airship in the vastness of the air). The damage that a single aeroplane can do to land defences or ships is, however, entirely trivial--at any rate at present.