areas marked out in or before the eighteenth century, regardless of the fact that a man or an army or an aeroplane can get in a few minutes or a few hours to points that it would have taken days or weeks to reach under the old foot-and-horse conditions.  That matters nothing to the learned men who instruct our statesmen and politicians.  It matters everything from the point of view of social and economic and political life.  And the grave fact to consider is that all the great states of Europe, except for the unification of Italy and Germany, are still much of the size and in much the same boundaries that made them strong and safe in the eighteenth century, that is to say, in the closing years of the foot-horse period.  The British empire grew and was organized under those conditions, and had to modify itself only a little to meet the needs of steam shipping.  All over the world are its linked possessions and its ports and coaling stations and fastnesses on the trade routes.  And British people still look at the red-splashed map of the world with the profoundest self-satisfaction, blind to the swift changes that are making that scattered empire—­if it is to remain an isolated system—­almost the most dangerous conceivable.

Let me ask the British reader who is disposed to sneer at the League of Nations and say he is very well content with the empire, thank you, to get his atlas and consider one or two propositions.  And, first, let him think of aviation.  I can assure him, because upon this matter I have some special knowledge, that long-distance air travel for men, for letters and light goods and for bombs, is continually becoming more practicable.  But the air routes that air transport will follow must go over a certain amount of land, for this reason that every few hundred miles at the longest the machine must come down for petrol.  A flying machine with a safe non-stop range of 1500 miles is still a long way off.  It may indeed be permanently impracticable because there seems to be an upward limit to the size of an aeroplane engine.  And now will the reader take the map of the world and study the air routes from London to the rest of the empire?  He will find them perplexing—­if he wants them to be “All-Red.”  Happily this is not a British difficulty only.  Will he next study the air routes from Paris to the rest of the French possessions?  And, finally, will he study the air routes out of Germany to anywhere?  The Germans are as badly off as any people.  But we are all badly off.  So far as world air transit goes any country can, if it chooses, choke any adjacent country.  Directly any trade difficulty breaks out, any country can begin a vexatious campaign against its neighbour’s air traffic.  It can oblige it to alight at the frontier, to follow prescribed routes, to land at specified places on those routes and undergo examinations that will waste precious hours.  But so far as I can see, no European statesman, German or Allied, have begun to give their attention to this amazing difficulty.  Without a great pooling of air control, either a world-wide pooling or a pooling at least of the Atlantic-Mediterranean Allies in one Air League, the splendid peace possibilities of air transport—­and they are indeed splendid—­must remain very largely a forbidden possibility to mankind.