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.

And as a second illustration of the way in which changing conditions are