and the battleship, which are sea-machines. Of course, a big tank can whip a little tank just as a big man can whip a little man. There is no more practical limit to the size of tanks than to that of naval vessels. The same rule probably holds true of aeroplanes. Consequently, as soon as the European powers begin to wriggle out of their present fix, we may expect them, with what margin they have, to begin a race of armament more expensive in proportion to their resources than the race of 1871–1914. The tank of today may be compared to a caravel. We shall have the destroyer-tank; then some nation will come along with the cruiser-tank, and the others must follow or underwrite defeat. And so on, up to the dreadnought tank—a gas-proofed fortress on caterpillar wheels, perhaps as complex and expensive as the sea-dreadnought. And if one alliance increases her fleet of land-dreadnoughts from a hundred to a hundred and twenty, from a thousand to twelve hundred, the rival alliance must let out another notch and follow. You may, if you wish, translate all this into terms of aircraft, and the economic result will be the same.
In the last war, nations learned that they must bend every resource, and especially every industrial resource, to victory. But some of them learned it rather late. Even Germany was for a long time manufacturing and exporting to the adjacent neutral countries such commodities as machinery. Later, in the fierce stress of the war, Germany turned all her
