The conduct of this battle fell to General Byng, commanding. the 3d Army, who made his preparations with great skill. Instead of using a long bombardment to destroy the enemy's wire entanglements he employed a large number of tanks sending them forward behind a barrage. By using the greatest care all the tanks were brought into position secretly, and the attack was a complete surprise for the Germans. The tanks made great gaps in the wire through which the infantry quickly passed. The outposts fell at once and the main line went soon afterward. By 10:30 A.m. the strongly tunneled reserve line of trenches was taken and the attacicing force confronted only a series of enemy rear positions. Against these places the attack was continued on the 21st, with some important gains. But the German resistance was not broken, and at the close of the day the British troops were exhausted and the Germans were bringing up fresh divisions. Here the lines remained five days with hard fighting and little advantage for either side.
The battle had now reached its crisis. The British had driven a salient into the German positions 10 miles wide and six deep, but they were unable to go farther and their opponents were concentrating superior forces ag-ainst them, preparing to pinch out the newly formed salient Had General Haig been able to. bring up an equal number of fresh troops and carry the movement on to a complete success it would have been well to proceed with the battle. Otherwise, prudence demanded that he break off the contest, fall back to a favorable position tions lmown as the battle of Cambrai •on the night of 7 December with his lines about two and a half miles nearer Cambrai than when the battle opened on 20 November. In the first week of the fighting the British took 10,500 prisoners and held 60 square miles of territory that had previously been occupied by the Ger mans. They had also inflicted losses that were heavier than they had sustained.
The battle of Cambrai was the last of the blows of attrition in the west In the future a way -was to be found to brealc through the trench system that had existed from September 1914, although neither side was to find a way by which the breach could be made to result in one of those great encircling movements that was the dream of military men on each side.
in the salient, and be satisfied with what he had won. To adopt such a course required more self-control than the British general displayed. Following the impulse to hold on in an extreme situation he remained where he was and re ceived the storm that General Ludendorff was preparing with great care. It broke on 30 November. A strenuous attack was delivered on each flank of the salient, while a furious charge was delivered on its centre. This triple action lasted from 30 November to 3 December, the British lines being pushed bacic on both flanks until the salient became dangerously narrow. Then General Haig was forced to realize that he must draw back his advanced lines.- During four clays' fighting he carried out the task of readjustment and ended the opera The Cambrai battle was notable for the success with which tanks were employed in it. These instruments of war, first used in the battle of the Somme, were originally hailed as a very dangerous fighting machine. They were con sidered a kind of mobile machine-gun nest. The Germans caught at the idea and tned to improve on it by malang still larger tanks, assuming that they would be more formidable through being larger. As a fighting machine, however, the tank was only moderately successful. Its best service was against wire entanglements, and it was in the battle of Cambrai that this use was given its earliest perfect demonstration. It was here shown that the tank, by doing the work of the initial bombardment, made it pos sible to employ the element of surprise, pro vided. there were adequate air protection and care in assembling the surprising forces.