devastated, villages were burnt, roads and railways destroyed, fruit trees cut down and everything of any value was removed, and min >,s which exploded at a touch were prepared with diaboli- cal ingenuity. In these circumstances a rapid pursuit became impossible and the Germans were able to delay the advance of the Allies by rearguards, while they removed their heavy artillery and established their main bodies in the Hindenburg lines.
This manoeuvre, planned and successfully carried through by Ludcndorff, effected a great change in the situation to the benefit of the Germans. Not only did it materially shorten their front and thereby enable them to increase their reserves, but their troops exchanged the battered defences of the Somme battlefield with its awkward salients for the strongest lines which had yet been _built upon the western front. Further, the enemy had withdrawn from a considerable part of the front which Nivelle had intended to attack, and this made necessary a fur- ther postponement of his battles, but he still adhered to the main features of his plan. In the altered circumstances grave doubts arose in the minds of some of the senior French generals as to the feasibility of this plan, and when these came to the ears of the French War Minister, M. Painleve, he assembled a Council of War on April 6, on the very eve of the offensive, at which criti- cs of the plan were presented by certain of the commanders ho were to take a leading part in its execution. Nevertheless, te French Government decided not to interfere with Gen. ivelle. It is difficult to conceive of a more unfortunate prelude a great battle. However, these doubts and hesitations of the leaders were not known to the rank and file of the army or to the French people; and when, on April o, the spring campaign began by an attack by Allenby's III. Army on the enemy's lines E. of Arras, and by the Canadian corps with one brigade of the 5th Div. on the Vimy Ridge, and met with an immediate success, hopes soared high. The French public was deeply impressed by the rapid capture of the Vimy Ridge, which had for so long resisted Foch's attacks, and great things were expected when the French army advanced.
The second of Nivelle's blows was delivered by the group of armies of the centre, now under Franchet d'Espercy, against the German front in the neighbourhood of St. Quentin; but Franchet d'Esperey was here in contact with a part of the main Hinden- burg line, and he had neither the time nor the means to prepare effectively for an attack upon their formidable defences. The operations of the centre group of armies, which had been intended to be an important part of Nivelle's programme, dwindled there- fore into little more than a demonstration, which took place on April 14 and had no material results. Nivelle's main battle, which took place on the front between Reims and Anizy, began on ril 16. It had been planned that the assaulting troops should the first day of battle break through the first three German ines. The attack was made by Mangin's VI. Army and Mazel's V. Army, with Duchesne's X. Army and a mass of cavalry in reserve ready to exploit their success. Antonine's IV. Army struck in to the E. of Reims on the iyth. The left of Mazel's attack failed almost entirely; and elsewhere, though the first German line was captured, little progress was made beyond it. The dream of a rapid rupture of the enemy's front had to be abandoned, and a fresh plan of battle had to be formed.
One of the first results of the failure of Nivelle to realize his hopes was that he had to request Haig to press his attacks to the E. of Arras with all possible vigour, so as to keep the largest possible number of Germans occupied in that quarter. This entailed a prolongation of the battle of Arras into a period when gains became small and were only purchased at great price. None the less Haig decided that the situation made it neces- sary to support the French with all his power, and he fought on till May 17, by which time the British front was estab- lished some 4 m. to the E. of Arras and in the plain to the E. of the Vimy Ridge. While Haig was thus battling in the N., Nivelle on the Aisne front had brought his X. Army into his front line, and by slow and bitter fighting had won his way up the Chemin des Dames ridge, of which he captured the eastern portion. Early in May it was quite evident that there was no prospect of
such a break-through as had been planned, and on the isth the French Government replaced Nivelle by General Petain, while General Foch, recalled from semi-retirement, became chief of the staff in Paris. Petain's first task was to wind up the operations on the Aisne front, and the battle ended definitely on May 20.
The spring campaign had proved a failure in comparison with what might have been, and still more in comparison with what Nivelle had promised, but its results were far from being insig- nificant. The German retreat in March, which was a direct con- sequence of the battle of the Somme, had at last brought about the attainment of one of the objects for which Joffre had been striving for so long. The Allies had now more elbow room on one of the most vital parts of their front, that which covered directly the roads to Amiens and Paris. Had the Germans in March igiB started from the positions which they held in Feb. 1917, and had their attacks progressed at the same rate, they would have entered Amiens on the second day of the battle, which would have ended with the German guns bombarding Abbeville and communication between the French and British armies severed. It is therefore not too much to say that the retreat which was forced upon the Germans by the battle of the Somme saved the Allies in the following year. But how much greater might the results have been if the plan formed by Joffre and Haig in the previous Nov. had been followed if the Germans had been pressed on the Somme battlefield during the winter, and if they had been attacked early in Feb. before their plans for retreat had been completed. Despite all the difficulties with which the successful conduct of that retreat by the Germans had con- fronted them, the Allied armies had in the battles of April and May captured 62,000 prisoners, 446 guns, and 1,000 machine- guns, and had gained positions of the first importance; 57 divi- sions had been compelled to fight upon the French front and 99 on the British front. Had Nivelle been content to follow Joffre's example, and to prepare methodically for the exhaustion of the German reserves without overtaxing the endurance of the sorely tried French army before attempting to break through the ene- my's lines, he might have claimed a conspicuous success for his first campaign. But the hopes which he had roused had been extravagant, and the dejection when they were not realized was correspondingly great. The dejection was increased by the news of the Russian revolution, and by exaggerated reports of the losses in the Aisne battles; and it was hardly alleviated by America's entry into the war, for it was well understood that American troops could not be ready to take their places in the firing line during 1917. The immediate consequence of this dejection was the outbreak of a series of mutinies in the French armies, which so affected the moral of the French troops that Petain found it necessary to appeal to Haig to keep the enemy engaged while he restored the confidence of his men.
If the attention of the Germans was to be occupied by the British armies it was necessary that they should be forced to fight. Upon any part of the British front S. of the point where it bends S. from the Belgian frontier N.W. of Lille it was possible for the Germans to repeat their manoeuvre of March and avoid a battle by retiring into another system of defences, for in doing this they would be merely abandoning a portion of French terri- tory which was of no great value to them, while they might by this method economize sufficient troops to enable them to fall upon the French. On the Belgian front they could not fall back without risking their hold upon the ports of Ostend and Zeebrugge, which were to them important bases for their submarine cam- paign, and without endangering the security of the chief aero- dromes from which their air attacks upon England were made. For these reasons Haig decided to press the enemy with all his available means upon the Belgian front, and on June 7 he began this campaign with the battle of Messines. This battle was most skilfully and thoroughly prepared by Sir Herbert Plumer, and was fought and won by his II. Army. The battle began with the explosion of a number of huge mines, the secret of which had been preserved by constant and devoted watchfulness on the part of the miners, who had tunnelled beneath the enemy's lines many months previously and awaited patiently the opportunity
