Gas, whatever its possibilities were before this protection was obtained, remains but a projectile evolved as above described. Tanks were a “creation,” and the introduction of the petrol-driven cross-country tractor on the battlefield, it is thought, will mark a definite close to the “alchemical” epoch of warfare. All war on land, in the past, has been based on muscular energy; henceforth it will be based on mechanical. The change is radical, and Wilson’s “Big Willie” will one day pass into legend alongside Stevenson’s “Rocket.” As steam, applied as a motive force, in 150 years changed the world more than it had previously been changed since the days of palæolithic man, so, before the present century has run its course, may as great a change take place in the realms of war. The cause of both is the same: as the invention of the steam engine rendered obsolete to a high degree the hand-tool and replaced it by the machine-tool, so the application of petrol to the battlefield will force the hand-weapon out of existence and replace it by the machine-weapon. That the tank will continue in its present form is as unlikely as it would have been to expect, in 1769, that Watt’s pumping engine was the “Ultima Thule” of all such engines. It is not the form which is the stroke of true genius, but the idea, the replacing of muscular energy by mechanical force as the motive power of an army.
Had the combatant nations of the Great War possessed more foresight, had they thought of war as a science in place of as an insurance policy, they could have had a steam-driven tank thirty years ago and a petrol-driven one immediately after the South African War. The Batter tractor existed, anyhow in design, in 1888, and during the South African War Mr. W. Ralston drew a comic picture entitled “Warfare of the Future: The Tractor Mounted Infantry in Action,” to say nothing about the story by Mr. H. G. Wells. But no, the breath of ancient battles had to be breathed, and whilst military students were studying Jena, Inkerman, and Worth, the commercial sciences were daily producing one invention after another which a little adjustment would help win the next war more speedily than the study of scores of Jominis and Clausewitzs.
To show how unscientific the soldiers of the 1870–1914 epoch had become it is only necessary to quote that after the battle of the Somme in the highest German military circles the machine was considered as a veritable joke. Apparently it could not be seen that, though the Mark I tank was far from perfect, it, being able to reintroduce armour and to provide the soldier with a mobile weapon platform, revolutionised the entire theory of 1870 warfare.
On July 1, 1916, the opening day of the battle of the Somme, the British Army sustained between 40,000 and 50,000 casualties. On September 25, one single tank forced the surrender of 370 Germans at a cost of five casualties to ourselves, yet in July 1917 the Mark IV tank was still considered but as a minor factor. Its design was not sufficiently reliable, its true powers were more or less a matter of conjecture; the troops were not fully accustomed to it, nor would they place sufficient faith in it to accept it in lieu of artillery support, in fact, in its present state of development the tank was but an adjunct to infantry and guns. Such were some of the views held regarding it when, like a bolt from the blue, the battle of Cambrai shot across the horizon of 1870 battles.
At Cambrai it was the Mark IV tank which was used, the same which had existed in July; the Tank Corps had not increased materially in size; the infantry were for the most part used-up troops—some had received a few days’ training with tanks, others had never even seen these machines. The assault was an overwhelming success: at the cost of some 5,000 infantry casualties an advance was made in twelve hours which in extent took ninety days at Ypres, and which in this last-named battle cost over a quarter of a million men. Yet, in spite of this astonishing success, so conservative had the Army grown to the true needs of victory that there were certain soldiers who now stated that the tactics employed at Cambrai could never be repeated again and that the day of the tank had come and gone.
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Then came the “crowning mercy”—the attack on Hamel. Something had to be done to reinstate the credit of the Tank Corps. There were but three suitable localities to do it in: the first, against the Merville salient—the ground here was bad, being intersected by dikes and canals; the second, eastward from between Arras and Hebuterne—the ground here was much cut up, and the tactical objective was not suitable; the third, eastwards from Villers-Bretonneux—the ground here was excellent, but the Australians, who held this sector, had little confidence in the tank.
Human prejudice is, however, not difficult to overcome to the student of psychology. After tactful persuasion the Australian Corps was induced to accept sixty machines, as an “adjunct” to their operations. The tanks (Mark V.s) were drawn up 1,000 yards in rear of the attackers, yet, nevertheless, within a few minutes of the attack being launched, they caught up with the leading wave and carried this wave and those in rear right through to the final objective. The loss of the 4th Australian Division was insignificant; their prejudices vanished and a close comradeship between them and the Tank Corps was established which redounds to their gallantry and common sense.
Hamel, minor incident though it was, was of more importance to the immediate problems of the British Army than Cambrai itself. General Rawlinson, commanding the Fourth Army, saw his opportunity, and the result was that from Hamel onwards the war became a tank war. The machine had made good in spite of prejudice and opposition. The Germans lost their heads, and with their heads they lost the war. That the war might have been won without tanks is quite possible, but that fifty-nine British divisions would, without their assistance, have beaten ninety-nine German ones in three months is extremely unlikely.
What had the influence of the tank really been? Let us examine this question and so close this retrospect.