for their use. The effect of these explosions, combined with a
very skilfully planned bombardment of massed guns of all
calibres, was such that, except in the right of the attack in the
neighbourhood of Messines, the infantry, for once, had little to
do. The whole of the Messines- Wytschaete ridge was captured
at comparatively very light cost, and the Ypres salient, a name
of ill omen for the British army since Oct. 1914, disappeared.
The strength of the British army in combatant troops was now at its greatest. Haig had 64 divisions and 10 cavalry divisions under his orders, and a mass of heavy artillery, tanks and aero- planes. It was well that this was so, for the army was to be called upon to endure greatly while Petain and his men got their second wind. Nor was it only the situation on the western front which called for resolute action, for the condition of the Russian army was far more critical than that of the French army. Kor- nilov had, on July i, begun an offensive, and if he was supported and encouraged by success in the W. it was still possible that the Russians might continue to be a powerful factor in the war.
With these heavy responsibilities on his shoulders,- Haig be- gan on July 31 the second battle of Ypres, with a great attack by the V. Army, which had been moved N. for the purpose. This attack was combined with a subsidiary attack by the French IV. Army under General Antoine on the British left. The object was to gain possession of the Passchendaele ridge, so as to be able to sweep with gun-fire the plains beyond it toward Zee- brugge and Ostend. This achieved, a combined naval and military attack, which had been secretly prepared in England, was to be made on the Belgian coast, which it was hoped would gain possession of the ports and so relieve the British Admiralty of some of the many anxieties caused by the German " U " boats. In preparation for the landing the British took over from the French the lines on the Belgian coast near Nieuport and moved other troops up to the coast behind these lines. The position at Nieuport, which consisted of a narrow strip of ground, with the Yser at its back, was not easy to hold against deter- mined attacks, and before the British preparations for defence were completed the Germans attacked and captured the lines E. of the river. This was an inauspicious beginning, but worse followed, for the weather broke immediately after the battle began and then followed a rainfall unprecedented for August.
The plan of battle was to deliver a series of blows, each with an objective limited by the support which the artillery could give without changing position. It was believed that the expe- rience of Messines and of Verdun had shown that this would allow the infantry to reach their objective without heavy loss. Ludendorff, however, met this method of attack by a new method which he called the elastic system of defence. He made no attempt to hold his front lines in strength, but withdrew the bulk of his infantry from the zone which would be most heavily bombarded and relied mainly upon machine-guns in concrete " pill-boxes " to break up the British infantry attack, and upon counter-attacks by the troops whom he had held back. But it was less this method of defence than the mud of Flanders which prevented British progress. The opening battle of July 31 gave the British possession of the whole of the Pilken Ridge, of the German first line of defence between Nordshoote and Klein Zillebeke, a front of 10 m., and of most of the German second line, but it was not until Sept. 20 that the enemy's third line was penetrated, and not until Oct. 4 that the British were estab- lished on the high ground between Broodseinde and Becelaere. The difficulty of getting guns and ammunition forward through the slough of mud prevented the delivery of a rapid succession of blows, each with a limited objective, as had been planned, and in the event a more terrible strain was imposed upon the British troops than in any other battle of the war. As in the case of the battle of the Somme, the first fruits of the third battle of Ypres were reaped elsewhere than on the battle-front. The Germans, forced to send more and more troops into the fiery furnace which blazed in the Ypres ridges, were, compelled to leave the French alone, and Petain had time to restore the confidence of his army. Part of his method was the delivery of very carefully prepared attacks on a comparatively small front, supported by a great
mass of artillery which should leave the infantry little more to do than to occupy the ground won. The first of these attacks was delivered by Guillaumat's II. Army on the Verdun front, and was completely successful, ending with the French in pos- session of all the ground which the Germans had won in 6 months fighting in 1916. This was followed by a more important attack delivered on Oct. 23 by Maitre's VI. Army, which gave the French the whole of the Chemin des Dames ridge, and resulted in the capture of 11,000 prisoners and 200 guns. Then and not till then Petain expressed himself as satisfied that his immediate purpose was achieved.
The British troops, struggling in the mud of Flanders, could not be told the reasons which had called for a supreme effort from them, and the terrible struggle through the mud, unrelieved by any conspicuous success, was a heavy strain upon them. As events turned out it would probably have been wiser to have brought the third battle of Ypres to a close immediately after the French had won the Chemin des Dames, but at that time the British were within a short distance of the crest of the Passchendaele ridge, while information received at G.H.Q. showed that the strain upon the German army had been far greater and that there had been a very appreciable lowering of the moral of the German troops. Haig had yet another blow in preparation. The continued bad weather and the slowness of the progress had caused the abandonment of the project of landing on the Belgian coast, and all hope of driving the Germans from the Belgian ports had gone, but there still appeared to be an opportunity of profiting from the exhaustion of the German reserves before the winter gave them a period for recovery, as it had after the battle of the Somme. A final reason for continuing -the struggle was that on Oct. 24 an Austro-German attack had been launched in Italy, and at Caporetto had broken through the Italian lines. It was therefore of importance to keep up the pressure upon the Germans on the western front. So the third battle of Ypres was continued, until the ridge and village of Passchendaele were captured on Nov. 3.
A fortnight later Byng's III. Army attacked the German front opposite Cambrai. This battle opened a new era in trench war- fare. One of the outstanding difficulties which the trench barrier had created was that it had hitherto eliminated one of the chief resources of generalship, surprise. The time and labour required to prepare for a great bombardment, and the accumulation of the huge stores of material of war on the selected front of battle, made it impossible to conceal intentions from the enemy. But at Cambrai these difficulties were overcome by using a great number of tanks, brought up secretly to take the place of the bombardment in breaking the enemy's defences. The attack was made upon one of the strongest parts of the Hindenburg system, but the tanks successfully broke through, and the surprise was complete. At Messines the guns had left nothing for the tanks to do, and in the third battle of Ypres they had been defeated by the mud of Flanders, but at Cambrai they came into their own. One thing alone was lacking as far as their part in the battle went. The cooperation between the tanks and the artillery in the later stages of the attack was not complete, so that numbers of tanks fell easy victims to the German guns, a lesson of which advantage was taken in 1018. Of greater importance was the fact that 6 French and 5 British divisions had been transferred to Italy to help the Italian army to stem the disaster of Caporetto, so that Haig had not the troops to complete and extend the first successes won at Cambrai. It is a typical illustration of the advantage which their central position conferred upon the Germans that several of the British divisions which would have been invaluable at Cambrai had not reached the Italian front at the time when the Austro-Germans were checked on the Piave.and the battle of Caporetto came to an end. So the German counter-attacks won back a good part of the ground which Byng had gained in the first advance, and the battle of Cambrai ended on Dec. 7 in one more disappoint- ment for the Allies.
The campaign of 1917 on the western front had been fatally hampered by the change of plan which had been made by
