“The Tank of to-day is a little thing compared with the obvious developments which will result in the Tank of the future, but even as it stands to-day it is the most economical fighting machine yet devised. A Tank uses petrol instead of muscle, and it extracts the highest possible fighting or killing value out of the men inside it; they can give their blows without being exposed to injury in return, and, above all things, they can fight while moving--a thing outside the powers of the infantry or guns of the land forces.” The arguments of those who maintain that the Tank must always be dependent upon the older arms are nearly all based upon the assumption that the Tank is already limited. “It is pointed out that they cannot cross rivers, that they are not proof against shell-fire, against mines, against special forms of attack. The answer is that the Tank of to-day may be subject to casualties, but all the skill and resources of the German nation have failed to produce an effective answer to Tanks, that river after river has been crossed, that line after line of ‘impregnable’ defences have fallen, that deeply écheloned artillery particularly arranged to fight Tanks has failed before Tank and aeroplane attack. We come to a war of sea, air, and land fleets acting in co-operation. Anti-Tank artillery is vulnerable to armoured planes. The big commercial freight-carrying planes of the future might even fly light Tanks into the heart of hostile territory. The unprotected men and arms of the present day must disappear.” And here another question is suggested--a question upon which the civilian ought to satisfy himself. Let us for the moment assume that it is superiority in weapons, not better generalship, not a more stubborn “will to win,” that decides the fate of war. What reason have we to suppose that it will be superiority in Tanks and not in some other weapon, in aeroplanes for example, that will decide the next conflict? At present, when we try to imagine war upon a foreign army waged on one side by air alone, we encounter a dozen mechanical difficulties even in our attempted picture of the first stages: the enormous paraphernalia of bases, the ground-staff, fuel, weather conditions, difficulties of landing, and finally, what is perhaps the fundamental difficulty. The aeroplane alone, like the big gun, is not an engine by whose means it is possible to come into decisive contact with an enemy who chooses to remain on the ground. The rabbits can always go to earth when they see the gliding shadow of the hawk. Till both sides are equipped solely for air combat, Tanks or infantry will still be needed to play the part of ferret. But these difficulties will almost certainly some day be overcome.