Three months of dreadful struggle came to an end with the British not appreciably nearer their immediate object of driving the Germans from their submarine bases in the Belgian ports, and if they had worn down the German strength they had worn down their own still more.
The 1917 cam paign in the West closed, however, on a note brighter in promise if not in accomplishment. Appreciating from the first days the futility of using tanks in these Flanders swamps, the Tank Corps headquarters looked around for an area where they could try out a new and different method. The chief general staff officer, Col. Fuller, drew up a project for a large scale raid to scour a canal enclosed "pocket" near Cambrai (q.v.), where the rolling down land lent itself to tank movement. The basic idea was the release of a swarm of tanks without any preparatory bombardment to give warning of the attack. When their hopes at Ypres waned, the British command adopted the scheme, retaining the basic idea, but transforming the operation into a definite offensive with far-reaching aims, for which they had not the resources because of the drain of Ypres. The operation was to be carried out by Byng's 3rd Army with six divisions, and the date was fixed for Nov. 20. Led by nearly 400 tanks, the attack came as a com plete surprise, and despite minor checks achieved a penetration far deeper and at less cost than any past British offensive. But all the available troops and tanks were thrown into the first blow, and the higher command failed to give Byng the few reserves they still possessed in time to exploit the success. The cavalry, as always throughout the operations on the Western front, proved totally unable to carry out this important role.
Thus the advance died away, and on Nov. 3o the German army commander, Marwitz, launched a counter-stroke against the flanks of the salient created by the British advance. In the north it was parried, but in the south broke through, and a disaster was only averted by the superb counter-attack, first of the Guards Division and later of a tank brigade. But if Cambrai was a disappointment it revealed that surprise and the tank were the combination by which the trench barrier could be unlocked. Meanwhile Petain, after overhauling his instrument, the French army, sought to test its readiness for 1918. In August a stroke
by Guillaumat's army recovered all the remainder of the ground lost in 1916, and in October Maistre's army flattened the south west corner of the German front, seizing the Chemin des Dames ridge.
The temporary breakdown of the French fighting power was not the worst of the troubles which together crippled the Entente offensive in 1917. The collapse, first partial and then complete, of Russia was a loss which even the entry of America into the war could not possibly compensate for many months, and before the balance was restored the West ern Allies were to be perilously near the brink of defeat. Russia's enormous losses, due to her awn defective machine but incurred in sacrifice for her Allies, had undermined the morale even more than the material endurance of her forces. Revolution broke out in March, superficially against the corrupt entourage of the tsar, but with more deep-seated moral causes beneath. The tsar was forced to abdicate and a moderate Provisional Government climbed into the saddle, but without reins. This was only a makeshift, and in May another succeeded it, more Socialist in tendency and outwardly led by Kerensky. While clamouring for a general peace and undermining discipline by a system of com mittee control suitable to a trade union but not to the field of battle, Kerensky imagined he could send troops against the enemy by platform appeals.
Brusilov succeeded Alexeiev in the supreme command, and on July r the army gained some initial success against the Austrians, especially in the region of Stanislau, only to stop as soon as real resistance was met, and to crumble directly the Germans counter attacked. By early August the Russians had been driven out of Galicia and the Bukovina, and it was only policy which halted the Austro-German forces on the frontiers of Russia itself. In September the Germans took the opportunity to practise their new method of attack intended for use in France, and this sur prise attack, under Hutier's command, resulted in the capture of Riga. Next month the Bolsheviks under Lenin overthrew the wordy Kerensky, imposed their self-constituted rule on the Rus sian people and sought an armistice with Germany, which was concluded in December.