close together to prevent the passage of tanks and of sufficient height to be unclimbable, and mine craters. In some cases elabo- rate chevaux-de-frise were erected across stretches of the front; " booby-traps " such as tank-pits were laid and certain areas in the later stages of the operations were flooded. Mines were employed to an increasing degree, sometimes in large minefields. It does not require a great amount of explosive to damage a tank, and the mines laid by the Germans were usually electro-contact, or mechanical " tread " mines, which were fired by the weight of a tank passing over them, the charge being a gun or trench- mortar shell. But land mines have the drawback of being dan- gerous to those who use them, and the greatest damage done to tanks by mines during the war was to the British machines manned by Americans in July 1918, by a British minefield pre- pared during the retreat in March and forgotten. On the whole, all these artificial obstacles proved a failure, for they could not be continuous, and could be avoided by a cross-country vehicle.
The Germans finally took the obvious step of producing a large-calibre, high-velocity machine-gun firing heavy armour- piercing bullets. This weapon, if fairly mobile, would have been an effective reply to the tank had it been introduced sooner. It was known as the " Tuf " (Tank und Flieger), was of i3-mm. calibre and could fire 200 bullets, said to be capable of piercing 30 mm. of hardened steel, a minute. Great efforts were made to produce it quickly and to keep its manufacture secret. Six thousand were to have been ready by April 1919, but by the Armistice none was in the field.
The greatest physical obstacle to the advance of tanks one form of defence experienced during the war was mud, and this was intensified by the concentrated and prolonged artillery fire which was generally carried out by both sides. In dry weather this rendered the ground almost impossible to negotiate and in wet weather made it absolutely impassable by any machine mov- ing on the surface of the ground. This was well exemplified during the third battle of Ypres in 1917, when the Germans could not have arranged a better defence against tanks than the morass created in the low-lying battlefield by the British guns. Here the conditions were such as to render futile the employment of tanks which was attempted. The best anti-tank defence beyond this half-natural, half-artificial obstacle, is, as has been said, the fire of suitable, mobile, light Q.F. artillery and carefully disposed minefields. Inundations are likely to be rendered use- less by the tank becoming an amphibious machine. ,
GENERAL CONCLUSIONS
The tank was the one complete British innovation in the war and a great one. The resurrection of an old weapon, it was forced into a fresh existence during hostilities by the needs of the war, and created for a special purpose. In essence it amounted to the addition of bullet-proof plate and armament to an exist- ing agricultural machine which possessed the quality of cross- country mobility. Its immediate purpose was the destruction of the machine-gun a weapon which, until the tank appeared, was responsible during the war for the loss of more human life than any other, and upon which the Germans at bay, on the defen- sive, placed so much reliance. With the machine-gun in this connexion is associated the wire obstacle. The combination of the two was the disease for which the tank proved to be the only cure; but, early as the disease was diagnosed, it had grown to be the scourge of the Allies on the western front, whenever they attempted to press forward as demanded by the strategic situation, long before the cure was applied. The tank was the great life-saver of the infantry. To it many thousands of the soldiers of the Allies, principally French and British, owed their lives infantrymen who but for the tanks would have had to repeat, on a larger scale and possibly abortively, the bloody offen- sives of 1915, 1916 and the first half of 1917. It took the place of the old stereotyped and expensive artillery preparations, with more certain results, and also reintroduced the surprise factor, which the preliminary bombardment prevented, and which the conditions of trench warfare otherwise rendered impossible without the protection to the infantry afforded by it.
A remarkable feature about the introduction of the British tanks was the fact that they were to a great extent forced on the army by the action of certain enthusiastic individuals, of whom one only was a serving soldier. Some of those, also, who were responsible for the creation of the new weapon, from the begin- ning formulated the tactics for its employment, which were finally after an inexplicably long period put into practice in the field. This was the case with the British and the French. The British first used tanks in Sept. 1916, and first employed them correctly on a large scale on Nov. 20 1917, 14 months later. The French first used tanks in April 1917, and first employed them correctly, on a large scale, on July 15 1918, also 14 months later. And in .each case this happened in spite of the proper method having been put forward, and its adaption urged. The only explanation of this policy is that it was due to inherent conservatism and lack of imagination, incredulity concerning the attributes of the new weapon, failure to understand what they implied, and initially lack of patience.
That the tanks achieved their object was shown by the prep- arations made by Great Britain, France, the United States, Italy and also Germany for the continuation of the struggle in 1919, and by the fact that their manufacture had begun to take up a large proportion of the munition-producing capacity of three at least of the combatants. In regard to results, it is only necessary to recall one major fact, so far as the British were con- cerned, i.e. that after the era of mechanical warfare, as it has been termed, set in, on Aug. 8 1918, and between that date and the Armistice, 59 British divisions were able to defeat 99 German divisions, a reversal of the proportion usually considered to hold between attackers and defenders. The offensive had at last obtained the superiority; and strength could no longer be esti- mated by the counting of heads. During the war the German infantry confessed itself impotent against tanks. But since the war not only have the infantry soldiers of other nations come to the same conclusion, but admit that they are often helpless without tanks to assist them. In certain circumstances they demand the assistance of these machines; and they are right. In regard to the influence of the new arm on the result of the war amongst a mass of corroborative evidence, one statement in- cludes and covers all others. On Oct. 2 1918, when the end was fast approaching, the report to the heads of the Reichstag parties made by the representatives of German military headquarters began with the following words 1 :
"The Chief Army Command has been compelled to take a terribly grave decision and declare that, according to human possibilities, there is no longer any prospect of forcing peace on the enemy. Above all two facts have been decisive for this issue. First, the Tanks. . . "
Such an admission, wrung after four years from those who had confidently started the World War, is sufficient.
In regard to the different ways in which tanks established their military value, apart from the actual results achieved, some instructive statistics have been prepared of their action from the aspect of the "economics" of war. 2 In fighting man-power a brigade of 144 tanks has a fire-power equivalent to that of 24 light batteries of six guns each, and nearly 200 more machine- guns than are carried in a division. An infantry division accom- panied by one battalion of tanks can attack three times the frontage that can be attacked by a division unaccompanied by tanks. The fighting infantry in three divisions is 21,000 men, of one tank battalion 500. The saving in man-power is therefore 13,500, or 63%, and with equivalent fire-power the chances of casualties are reduced. As to economy in infantry casualties, the losses on the firs"t day at the battle of Cambrai (a tank battle) were approximately 1,000 per division engaged; at the battle of the Somme (an artillery battle) there were 3,000. Between July and Nov. 1917, when tanks were used on impossi- ble ground 258,000 casualties were sustained by the British; between July and Nov. 1918, when tanks were used on possible
1 Report by Col. Bauer, Chief of the Artillery Department.
- The Gold Medal (Military) Prize Essay for 1919 by Brevet-Col.
J. F. C. Fuller (Journal of the Royal United Service Institution, May 1920). These statistics refer to the experience of the British.
