What lies behind the Tank depends upon this fact; there is no definable upward limit of mass. Upon that I would lay all the stress possible, because everything turns upon that.
You cannot make a land ironclad so big and heavy but that you cannot make a caterpillar track wide enough and strong enough to carry it forward. Tanks are quite possible that will carry twenty-inch or twenty-five inch guns, besides minor armament. Such Tanks may be undesirable; the production may exceed the industrial resources of any empire to produce; but there is no inherent impossibility in such things. There are not even the same limitations as to draught and docking accommodation that sets bounds to the size of battleships. It follows, therefore, as a necessary deduction that if the world's affairs are so left at the end of the war that the race of armaments continues, that Tank will develop steadily into a tremendous instrument of warfare, driven by engines of scores of thousands of horse-power, tracking on a track scores of hundreds of yards wide and weighing hundreds or thousands of tons. Nothing but a world agreement not to do so can prevent this logical development of the land ironclad. Such a structure will make wheel-ruts scores of feet deep; it will plough up, devastate and destroy the country it passes over altogether.
For my own part I never imagined the land ironclad idea would get loose into war. I thought that the military intelligence was essentially unimaginative and that such an aggressive military power as Germany, dominated by military people, would never produce anything of the sort. I thought that this war would be fought out without Tanks and that then war would come to an end. For of course it is mere stupidity that makes people doubt the ultimate ending of war. I have been so far justified in these expectations of mine, that it is not from military sources that these things have come. They have been thrust upon the soldiers from without. But now that they are loose, now that they are in war, we have to face their full possibilities, to use our advantage in them and press on to the end of the war. In support of a photo-aero directed artillery, even our present Tanks can be used to complete an invisible offensive. We shall not so much push as ram. It is doubtful if the Germans can get anything of the sort into action before six months are out. We ought to get the war on to German soil before the Tanks have grown to more than three or four times their present size. Then it will not matter so much how much bigger they grow. It will be the German landscape that will suffer.
After one has seen the actual Tanks it is not very difficult to close one's eyes and figure the sort of Tank that may be arguing with Germany in a few months' time about the restoration of Belgium and Serbia and France, the restoration of the sunken tonnage, the penalties of the various Zeppelin and submarine murders, the freedom of seas and land alike from piracy, the evacuation of all Poland including Posen and Cracow, and the guarantees for the future peace of Europe. The machine will be perhaps as big as a destroyer and more heavily armed and equipped. It will swim over and through the soil at a pace of ten or twelve miles an hour. In front of it will be corn, land, neat woods, orchards, pasture, gardens, villages and towns. It will advance upon its belly with a swaying motion, devouring the ground beneath it. Behind it masses of soil and rock, lumps of turf, splintered wood, bits of houses, occasional streaks of red, will drop from its track, and it will leave a wake, six or seven times as wide as a high road, from which all soil, all cultivation, all semblance to cultivated or cultivatable land will have disappeared. It will not even be a track of soil. It will be a track of subsoil laid bare. It will be a flayed strip of nature. In the course of its fighting the monster may have to turnabout. It will then halt and spin slowly round, grinding out an arena of desolation with a diameter equal to its length. If it has to retreat and advance again these streaks and holes of destruction will increase and multiply. Behind the fighting line these monsters will manoeuvre to and fro, destroying the land for all ordinary agricultural purposes for ages to come. The first imaginative account of the land ironclad that was ever written concluded with the words, “They are the reductio ad absurdum of war.” They are, and it is to the engineers, the ironmasters, the workers and the inventive talent of Great Britain and France that we must look to ensure that it is in Germany, the great teacher of war, that this demonstration of war's ultimate absurdity is completed.
For forty years Frankenstein Germany invoked war, turned every development of material and social science to aggressive ends, and at last when she felt the time was ripe she let loose the new monster that she had made of war to cow the spirit of mankind. She set the thing trampling through Belgium. She cannot grumble if at last it comes home, stranger and more dreadful even than she made it, trampling the German towns and fields with German blood upon it and its eyes towards Berlin.
This logical development of the Tank idea may seem a gloomy prospect for mankind. But it is open to question whether the tremendous development of warfare that has gone on in the last two years does after all open a prospect of unmitigated gloom. There has been a good deal of cheap and despondent sneering recently at the phrase, “The war that will end war.” It is still possible to maintain that that may be a correct description of this war. It has to be remembered that war, as the aeroplane and the Tank have made it, has already become an impossible luxury for any barbaric or uncivilised people. War on the grade that has been achieved on the Somme predicates an immense industrialism behind it. Of all the States in the world only four can certainly be said to be fully capable of sustaining war at the level to which it has now been brought upon the western front. These are Britain, France, Germany, and the United States of America. Less certainly equal to the effort are Italy, Japan, Russia, and Austria. These eight powers are the only powers capable of warfare under modern conditions. Five are already Allies and one is incurably pacific. There is no other power or people in the world that can go to war now without the consent and connivance of these great powers. If we consider their alliances, we may count it that the matter rests now between two groups of Allies and one neutral power. So that while on the one hand the development of modern warfare of which the Tank is the present symbol opens a prospect of limitless senseless destruction, it opens on the other hand a prospect of organised world control. This Tank development must ultimately bring the need of a real permanent settlement within the compass of the meanest of diplomatic intelligences. A peace that will restore competitive armaments has now become a less desirable prospect for everyone than a continuation of the war. Things were bad enough before, when the land forces were still in a primitive phase of infantry, cavalry and artillery, and when the only real race to develop monsters and destructors was for sea power. But the race for sea power before 1914 was mere child's play to the breeding of engineering monstrosities for land warfare that must now follow any indeterminate peace settlement. I am no blind believer in the wisdom of mankind, but I cannot believe that men are so insensate and headstrong as to miss the plain omens of the present situation.
So that after all the cheerful amusement the sight of a Tank causes may not be so very unreasonable. These things may be no more than one of those penetrating flashes of wit that will sometimes light up and dispel the contentions of an angry man. If they are not that, then they are the grimmest jest that ever set men grinning. Wait and see, if you do not believe me.