CHAPTER XVIII
ORIGINS OF THE BATTLE OF CAMBRAI
The battles of 1914 were primarily infantry battles based on the power of the rifle, and it was not until 1915 that the quick-firing gun and the heavy howitzer began to replace the rifle as the reducers of resistance to the infantry attack.
In 1915, as far as the British Army is concerned, it may be said that artillery was generally looked upon as an adjunct to the infantry. This idea died hard, and it was not until the battle of the Somme was half way through that it became apparent that it was no longer a question of guns co-operating in the infantry advance, but of the infantry itself co-operating with the artillery bombardments. In other words the limit of the infantry advance was the limit of the range of the guns, particularly the 18-pounders. This meant that no penetration of a greater depth than about 4,000 yards could be effected unless a second echelon of guns and infantry was launched and brought into action simultaneously with or just before the first assault had reached the range limit of the guns which were supporting it.
Two factors prohibited this from being done; the first was the heavily shelled area which usually extends over the whole 4,000 yards of the initial advance; the second, the great difficulty of keeping the second echelon of guns supplied with sufficient ammunition to maintain the second barrage. The shelled area not only prohibited the movement of guns for days, but produced such exhaustion on the second echelon of infantry crossing it, that by the time it caught up with the first echelon its men were too fatigued to continue the attack.
By some it was hoped that the tank would partially overcome this difficulty if it were brought into action on the area over which the 18-pounder barrage was beginning to fail, and by producing a local barrage of its own, by means of its machine guns, that it would cover any advance from 4,000 yards onwards.
This idea, though perfectly sound in itself, was doomed to failure as long as the conditions of ground produced by artillery fire rendered it impossible to support these tanks by infantry in fighting condition.
The first solution to this problem was to cease using heavy artillery on ground to be traversed by the infantry attackers. This, however, is at best but a half measure, for though, in the present phase of the war, co-operation between infantry and tanks was of vital importance, this co-operation could not be maintained for long if one arm has to rely on its muscular power, whilst the other relies on petrol as its motive force. At best, the advance of 4,000 to 6,000 yards will be extended to 8,000 or 12,000 yards, when the endurance of the infantry will reach its limit and the advance automatically cease. This is not sufficient, for in a war such as was being waged in 1917 (a trench war), in order to beat an enemy, the first necessity was to prevent him using his spade. This can only be done by maintaining a continuous, if comparatively slow advance, that is, by replacing muscle by petrol as the motive force. This means the creation of a mechanical army.
In August 1917 the Tank Corps fully realised that the creation of such an army, even on a very small scale, would take at least a year; further, that its creation depended on the value of the tank being fully recognised by those who could create such an army, and upon this army being used in a suitable area of operations. Consequently the first thing to do was to discover a suitable tank area; the second, to hold a tactical demonstration on it with tanks so as to convince the General Staff of their power and value. These steps it was felt would have to be taken before the petrol engine would be accepted as the motive force of the modern battle.