WORLD WAR I

also called First World War, or Great War an international conflict that in 191418 embroiled most of the nations of Europe along with Russia, the United States, the Middle East, and other regions. The war pitted the Central Powersmainly Germany, Austria-Hungary, and Turkeyagainst the Alliesmainly France, Great Britain, Russia, Italy, Japan, and, from 1917, the United States. It ended with the defeat of the Central Powers. Europe and the Mediterranean during World War I. By 1910 the major nations of Europe had aligned themselves into two potentially hostile alliances, with Germany and Austria in one and France, Great Britain, and Russia in the other. When a Serbian nationalist assassinated Archduke Francis Ferdinand of Austria at Sarajevo on June 28, 1914, a chain of threats, ultimatums, and mobilizations was set in motion that resulted in a general war between these two alliances by mid-August. German and Allied movements on the Western Front, AugustSeptember 1914. Germany had long been prepared to fight a land war on two frontsi.e., against France on the west and against Russia on the east. In the west its armies outflanked France's main defensive forces and swept westward through Belgium, thereby bringing Great Britain into the war by treaty obligation. The German armies then turned south toward Paris. The French, reinforced by a British Expeditionary Force, managed to stabilize their defensive lines by November along the Aisne River, thereby saving Paris, but this meant that the rest of the war in that theatre was fought on French territory. Because of the tremendous firepower of modern artillery and machine guns, the war quickly evolved into one of attrition fought from lines of trenches. Frontal infantry assaults typically gained ground only by yards, and these attacks, whether successful or not, were enormously costly in human life. A deadlock soon ensued on the Western Front that could not be broken even by the enormous battles of the Somme and Verdun (both 1916) or by the massive German offensives of early 1918. The Eastern Front, 191417. In the east an early Russian offensive in 1914 drove deep into East Prussia, German Poland, and Galicia, but the Russians were stopped by German and Austrian forces by the end of the year, and, in a startling German offensive begun in May 1915, they were thrown back into their own territory. Though it mounted several more offensives and suffered enormous casualties, the Russian army proved unable either to break through the German defensive lines or to take any German territory. Other fronts in the war were to a greater or lesser extent peripheral to the main theatres but were nonetheless bloody. They included Gallipoli and the Dardanelles, where Britain unsuccessfully attempted to invade Turkey proper; the Caucasus and Persia, where Russia and Turkey fought; Mesopotamia and Egypt, where British forces (and, in Egypt, the Arabs organized by T.E. Lawrence) fought the Turks; and the Isonzo valley northwest of Trieste, where Italian and Austrian troops fought a long series of costly battles. At sea only Germany and Great Britain had substantial fleets. Britain attempted, with considerable success, to blockade Germany and cut off its maritime access to food and raw materials from overseas. In response Germany turned to one of its newest weapons, the submarine, to interrupt the maritime supply lines of the British Isles. Germany's policy of unrestricted submarine warfare, however, which led to the sinking of much neutral shipping, ultimately persuaded the United States to enter the war against Germany in 1917. The major naval engagement of the warindeed, one of the largest naval battles in historywas the inconclusive Battle of Jutland fought between the British Grand Fleet and the German High Seas Fleet in May 1916. Russia's poor performance in the war and its grievous losses inspired widespread domestic discontent that led to the overthrow of the Russian monarchy in early 1917 and to the Bolshevik Revolution in November of that year. At the Bolshevik leader Lenin's order, Russia unilaterally ceased hostilities on November 26 and a month later signed a formal armistice with Germany, thus withdrawing from participation in the war. The release of German forces in the east for service on the deadlocked Western Front, however, was offset by the arrival of U.S. troops in France. Used tentatively at first, the rapidly reinforced American forces1,200,000 by September 1918soon proved their worth. By autumn 1918 the position of the Central Powers had deteriorated rapidly. The Austro-Hungarian Empire, shaken by military defeats and by nationalist uprisings encouraged by the Russian Revolution, virtually disintegrated during October. Germany's great offensives on the Western Front during April-July failed, and the Allied forces then began a steady advance that recovered almost all of German-occupied France and part of Belgium by October 1918. German military and civilian morale thereupon collapsed, and amid widespread political unrest the German kaiser William II abdicated on November 9. Two days later an Armistice was signed between Germany and the Allies at Rethondes, Fr., thus ending World War I. also called First World War, or Great War an international conflict that in 191418 embroiled most of the nations of Europe along with Russia, the United States, the Middle East, and other regions. The war pitted the Central Powersmainly Germany, Austria-Hungary, and Turkeyagainst the Alliesmainly France, Great Britain, Russia, Italy, Japan, and, from 1917, the United States. It ended with the defeat of the Central Powers. The war was virtually unprecedented in the slaughter, carnage, and destruction it caused. World War I was one of the great watersheds of 20th-century geopolitical history. It led to the fall of four great imperial dynasties (in Germany, Russia, Austria-Hungary, and Turkey), resulted in the Bolshevik Revolution in Russia, and, in its destabilization of European society, laid the groundwork for World War II. Additional reading Dwight E. Lee (ed.), The Outbreak of the First World War: Causes and Responsibilities, 4th ed. (1975), is a good introduction to the debate on the origins of World War I. A more detailed account is provided in Luigi Albertini, The Origins of the War of 1914, 3 vol. (195257, reprinted 1980; originally published in Italian, 194243). A comprehensive general account of the war is Bernadotte E. Schmitt and Harold C. Vedeler, The World in the Crucible, 19141919 (1984). The standard military histories are Basil Henry Liddell Hart, A History of the World War, 19141918, enl. ed. (1934, reprinted 1970); Cyril B. Falls, The Great War (1959); and Marc Ferro, The Great War, 19141918 (1973, reprinted 1987; originally published in French, 1969). J.E. Edmonds (comp.), A Short History of World War I (1951, reprinted 1968); and John Terraine, The Great War, 19141918: A Pictorial History (1965, reprinted 1978), are useful introductions. Naval operations during the war are discussed in Arthur J. Marder, From the Dreadnought to Scapa Flow: The Royal Navy in the Fisher Era, 19041919, 5 vol. (196170). International diplomacy during the war is treated in Z.A.B. Zeman, The Gentlemen Negotiators (1971; U.K. title, A Diplomatic History of the First World War). John Graham Royde-Smith The Editors of the Encyclopdia Britannica The last offensives and the Allies' victory The Western Front, MarchSeptember 1918 German offensives on the Western Front, MarchJuly 1918. As the German strength on the Western Front was being steadily increased by the transfer of divisions from the Eastern Front (where they were no longer needed since Russia had withdrawn from the war), the Allies' main problem was how to withstand an imminent German offensive pending the arrival of massive reinforcements from the United States. Eventually Ptain persuaded the reluctant Haig that the British with 60 divisions should extend their sector of the front from 100 to 125 miles as compared with the 325 miles to be held by the French with approximately 100 divisions. Haig thus devoted 46 of his divisions to the front from the Channel to Gouzeaucourt (southwest of German-held Cambrai) and 14 to the remaining third of the front from Gouzeaucourt past German-held Saint-Quentin to the Oise River. On the German side, between Nov. 1, 1917, and March 21, 1918, the German divisions on the Western Front were increased from 146 to 192, the troops being drawn from Russia, Galicia, and Italy. By these means the German armies in the west were reinforced by a total of about 570,000 men. Ludendorff's interest was to strike from his temporary position of strengthbefore the arrival of the major U.S. contingentsand at the same time to ensure that his German offensive should not fail for the same reasons as the Allies' offensives of the past three years. Accordingly he formed an offensive strategy based on taking the tactical line of least resistance. The main German attacks would begin with brief but extremely intense artillery bombardments using a high proportion of poison gas and smoke shells. These would incapacitate the Allies' forward trenches and machine-gun emplacements and would obscure their observation posts. Then a second and lighter artillery barrage would begin to creep forward over the Allied trenches at a walking pace (in order to keep the enemy under fire), with the masses of German assault infantry advancing as closely as possible behind it. The key to the new tactics was that the assault infantry would bypass machine-gun nests and other points of strong resistance instead of waiting, as had been the previous practice on both sides, for reinforcements to mop up the obstructions before continuing the advance. The Germans would instead continue to advance in the direction of the least enemy resistance. The mobility of the German advance would thus be assured, and its deep infiltration would result in large amounts of territory being taken. Such tactics demanded exceptionally fit and disciplined troops and a high level of training. Ludendorff accordingly drew the best troops from all the Western Front forces at his disposal and formed them into elite shock divisions. The troops were systematically trained in the new tactics, and every effort was also made to conceal the actual areas at which the German main attacks would be made. Ludendorff's main attack was to be on the weakest sector of the Allies' front, the 47 miles between Arras and La Fre (on the Oise). Two German armies, the 17th and the 2nd, were to break through the front between Arras and Saint-Quentin, north of the Somme, and then wheel right so as to force most of the British back toward the Channel, while the 18th Army, between the Somme and the Oise, protected the left flank of the advance against counterattack from the south. Code-named Michael, this offensive was to be supplemented by three other attacks: St. George I against the British on the Lys River south of Armentires; St. George II against the British again between Armentires and Ypres; and Blcher against the French in Champagne. It was finally decided to use 62 divisions in the main attack, Michael. Preceded by an artillery bombardment using 6,000 guns, Michael was launched on March 21, 1918, and was helped by an early morning fog that hid the German advance from the Allied observation posts. The attack, which is known as the Second Battle of the Somme or the Battle of Saint-Quentin, took the British altogether by surprise, but it did not develop as Ludendorff had foreseen. While the 18th Army under von Hutier achieved a complete breakthrough south of the Somme, the major attack to the north was held up, mainly by the British concentration of strength at Arras. For a whole week Ludendorff, in violation of his new tactical emphasis, vainly persisted in trying to carry out his original plan instead of exploiting the unexpected success of the 18th Army, though the latter had advanced more than 40 miles westward and had reached Montdidier by March 27. At last, however, the main effort of the Germans was converted into a drive toward Amiens, which began in force on March 30. By that time the Allies had recovered from their initial dismay, and French reserves were coming up to the British line. The German drive was halted east of Amiens and so too was a renewed attack on April 4. Ludendorff then suspended his Somme offensive. This offensive had yielded the largest territorial gains of any operation on the Western Front since the First Battle of the Marne in September 1914. The Allies' cause at least derived one overdue benefit from the collapse of one-third of the British front: at Haig's own suggestion, Foch was on March 26 appointed to coordinate the Allies' military operations; and on April 14 he was named commander in chief of the Allied armies. Previously, Haig had resisted the idea of a generalissimo. On April 9 the Germans began St. George I with an attack on the extreme northern front between Armentires and the canal of La Basse, their aim being to advance across the Lys River toward Hazebrouck. Such was the initial success of this attack that St. George II was launched the next day, with the capture of Kemmel Hill (Kemmelberg), southwest of Ypres, as its first objective. Armentires fell, and Ludendorff came to think for a time that this Battle of the Lys might be turned into a major effort. The British, however, after being driven back 10 miles, halted the Germans short of Hazebrouck. French reinforcements began to come up; and, when the Germans had taken Kemmel Hill (April 25), Ludendorff decided to suspend exploitation of the advance, for fear of a counterstroke against his front's new bulge. Thus far Ludendorff had fallen short of strategic results, but he could claim huge tactical successesthe British casualties alone amounted to more than 300,000. Ten British divisions had to be broken up temporarily, while the German strength mounted to 208 divisions, of which 80 were still in reserve. A restoration of the balance, however, was now in sight. A dozen U.S. divisions had arrived in France, and great efforts were being made to swell the stream. Furthermore, Pershing, the U.S. commander, had placed his troops at Foch's disposal for use wherever required. Ludendorff finally launched Blcher on May 27, on a front extending from Coucy, north of Soissons, eastward toward Reims. The Germans, with 15 divisions, suddenly attacked the seven French and British divisions opposing them, swarmed over the ridge of the Chemin des Dames and across the Aisne River, and, by May 30, were on the Marne, between Chteau-Thierry and Dormans. Once again the attack's initial success went far beyond Ludendorff's expectation or intention; and, when the Germans tried to push westward against the right flank of the Allies' Compigne salient, which was sandwiched between the Germans' Amiens and Champagne bulges, they were checked by counterattacks, which included one sustained for a fortnight from June 6 by U.S. divisions at Belleau Wood (Bois de Belleau). An attack from Noyon, against the left flank of the Compigne salient, came too late (June 9). Overtaken by the inordinate fruition of his own offensives, Ludendorff paused for a month's recuperation. The tactical success of his own blows had been his undoing; yielding to their influence, he had pressed each too far and too long, using up his own reserves and causing an undue interval between blows. He had driven three great wedges into the Allied lines, but none had penetrated far enough to sever a vital rail artery, and this strategic failure left the Germans with a front whose several bulges invited flanking counterstrokes. Moreover, Ludendorff had used up many of his shock troops in the attacks, and the remaining troops, though strong in numbers, were relatively lower in quality. The Germans were to end up sustaining a total of 800,000 casualties in their great 1918 offensives. Meanwhile, the Allies were now receiving U.S. troops at the rate of 300,000 men per month. The next German offensive, which opened the Second Battle of the Marne, was launched in Champagne on July 15. It came to nothing: a German thrust from the front east of Reims toward Chlons-sur-Marne was frustrated by the elastic defense that Ptain had recently been prescribing but that the local commanders had failed to practice against the offensive of May 27. A drive from Dormans, on the left flank of the Germans' huge SoissonsReims bulge, across the Marne toward pernay simply made the Germans' situation more precarious when Foch's long-prepared counterstroke was launched on July 18. In this great counterstroke one of Foch's armies assailed the Germans' Champagne bulge from the west, another from the southwest, one more from the south, and a fourth from the vicinity of Reims. Masses of light tanksa weapon on which Ludendorff had placed little reliance, preferring gas instead in his plans for the yearplayed a vital part in forcing the Germans into a hasty retreat. By August 2 the French had pushed the Champagne front back to a line following the Vesle River from Reims and then along the Aisne to a point west of Soissons. Having recovered the initiative, the Allies were determined not to lose it, and for their next blow they chose again the front north and south of the Somme. The British 4th Army, including Australian and Canadian forces, with 450 tanks, struck the Germans with maximum surprise on Aug. 8, 1918. Overwhelming the German forward divisions, who had failed to entrench themselves adequately since their recent occupation of the Michael bulge, the 4th Army advanced steadily for four days, taking 21,000 prisoners and inflicting as many or more casualties at the cost of only about 20,000 casualties to itself, and halting only when it reached the desolation of the old battlefields of 1916. Several German divisions simply collapsed in the face of the offensive, their troops either fleeing or surrendering. The Battle of Amiens was thus a striking material and moral success for the Allies. Ludendorff put it differently: August 8 was the black day of the German Army in the history of the war . . . It put the decline of our fighting power beyond all doubt . . . The war must be ended. He informed Emperor William II and Germany's political chiefs that peace negotiations should be opened before the situation became worse, as it must. The conclusions reached at a German Crown Council held at Spa were that We can no longer hope to break the war-will of our enemies by military operations, and the objects of our strategy must be to paralyse the enemy's war-will gradually by a strategic defensive. In other words, the German high command had abandoned hope of victory or even of holding their gains and hoped only to avoid surrender. Meanwhile, the French had retaken Montdidier and were thrusting toward Lassigny (between Roye and Noyon); and on August 17 they began a new drive from the Compigne salient south of Noyon. Then, in the fourth week of August, two more British armies went into action on the ArrasAlbert sector of the front, the one advancing directly eastward on Bapaume, the other operating farther to the north. From then on Foch delivered a series of hammer blows along the length of the German front, launching a series of rapid attacks at different points, each broken off as soon as its initial impetus waned, and all close enough in time to attract German reserves, which consequently were unavailable to defend against the next Allied attack along a different part of the front. By the early days of September the Germans were back where they had been before March 1918behind the Hindenburg Line. The Allies' recovery was consummated by the first feat executed by Pershing's U.S. forces as an independent army (hitherto the U.S. divisions in France had fought only in support of the major French or British units): the U.S. 1st Army on September 12 erased the triangular Saint-Mihiel salient that the Germans had been occupying since 1914 (between Verdun and Nancy). The clear evidence of the Germans' decline decided Foch to seek victory in the coming autumn of 1918 instead of postponing the attempt until 1919. All the Allied armies in the west were to combine in a simultaneous offensive. Other developments in 1918 Czechs, Yugoslavs, and Poles Something must now be said about the growth of the national movements, which, under the eventual protection of the Allies, were to result in the foundation of new states or the resurrection of long-defunct ones at the end of the war. There were three such movements: that of the Czechs, with the more backward Slovaks in tow; that of the South Slavs, or Yugoslavs (Serbs, Croats, and Slovenes); and that of the Poles. The Czech country, namely Bohemia and Moravia, belonged in 1914 to the Austrian half of the Habsburg monarchy, the Slovak to the Hungarian half. The Yugoslavs had already been represented in 1914 by two independent kingdoms, Serbia and Montenegro, but they were also predominantly numerous in territories still under Habsburg rule: Serbs in Bosnia and Hercegovina (an Austro-Hungarian condominium) and in Dalmatia (an Austrian possession); Croats in Croatia (Hungarian), in Istria (Austrian), and in Dalmatia; Slovenes in Istria and in Illyria (Austrian likewise). Poland was divided into three parts: Germany had the north and the west as provinces of the Kingdom of Prussia; Austria had Galicia (including an ethnically Ukrainian extension to the east); Russia had the rest. The Czechs had long been restless under the Austrian regime, and one of their leading intellectual spokesmen, Tom Masaryk (in fact a Slovak), had already envisaged the carving of Czechoslovak and Yugoslav states out of Austria-Hungary in December 1914. In 1916 he and a fellow migr, Edvard Bene, based respectively in London and in Paris, organized a Czechoslovak National Council. The western Allies committed themselves to the Czechoslovak idea from 1917 onward, when Russia's imminent defection from the war made them ready to exploit any means at hand for the disabling of Austria-Hungary; and Wilson's sympathy was implicit in his successive peace pronouncements of 1918. For the South Slavs of Austria-Hungary the Yugoslav Committee, with representatives in Paris and in London, was founded in April 1915. On July 20, 1917, this committee and the Serbian government in exile made the joint Corfu Declaration forecasting a South Slav state to comprise Serbs, Croats, and Slovenes. The Polish nationalist leaders in the first years of the war were uncertain whether to rely on the Central Powers or on the Allies for a restoration of Poland's independence. So long as the western Allies hesitated to encourage Polish nationalism for fear of offending imperial Russia, the Central Powers seemed to be the most likely sponsors; and Austria at least allowed Jzef Pilsudski, from 1914, to organize his volunteer Polish legions to serve with Austrian forces against the Russians. Austria's benevolence, however, was not reflected by Germany; and when the Two Emperors' Manifesto of Nov. 5, 1916, provided for the constitution of an independent Polish kingdom, it was clear that this kingdom would consist only of Polish territory conquered from Russia, not of any German or Austrian territory. When, after the March Revolution of 1917, the Russian provisional government had recognized Poland's right to independence, Roman Dmowski's Polish National Committee, which from 1914 had been functioning in a limited way under Russian protection, could at last count seriously on the sympathy of the western Allies. While Pilsudski declined to raise a Polish army to fight on against the new Russia, a Polish army was formed in France, as well as two army corps in Belorussia and in the Ukraine, to fight against the Central Powers. The Bolshevik Revolution and Wilson's Fourteen Points together consummated the alignment of the Poles on the side of the western powers. The years of stalemate Rival strategies and the Dardanelles campaign, 191516 By late 1914 the state of deadlock on the Western Front had become clear to the governments of the warring countries and even to many members of their general staffs. Each side sought a solution to this deadlock, and the solutions varied in form and manner. Erich von Falkenhayn had succeeded the dispirited Moltke as chief of the German general staff in September 1914. By the end of 1914 Falkenhayn seems to have concluded that although the final decision would be reached in the West, Germany had no immediate prospect of success there, and that the only practicable theatre of operations in the near future was the Eastern Front, however inconclusive those operations might be. Falkenhayn was convinced of the strength of the Allied trench barrier in France, so he took the momentous decision to stand on the defensive in the West. Falkenhayn saw that a long war was now inevitable and set to work to develop Germany's resources for such a warfare of attrition. Thus, the technique of field entrenchment was carried to a higher pitch by the Germans than by any other country; Germany's military railways were expanded for the lateral movement of reserves; and the problem of the supply of munitions and of the raw materials for their manufacture was tackled so energetically and comprehensively that an ample flow was ensured from the spring of 1915 onwarda time when the British were only awakening to the problem. Here were laid the foundations of that economic organization and utilization of resources that was to be the secret of Germany's power to resist the pressure of the British blockade. The western Allies were divided into two camps about strategy. Joffre and most of the French general staff, backed by the British field marshal Sir John French, argued for continuing assaults on the Germans' entrenched line in France, despite the continued attrition of French forces that this strategy entailed. Apart from this, the French high command was singularly lacking in ideas to break the deadlock of trench warfare. While desire to hold on to territorial gains governed the German strategy, the desire to recover lost territory dominated the French. British-inspired solutions to the deadlock crystallized into two main groups, one tactical, the other strategical. The first was to unlock the trench barrier by inventing a machine that would be invulnerable to machine guns and capable of crossing trenches and would thus restore the tactical balance upset by the new preponderance of defensive over offensive power. The idea of such a machine was conceived by Colonel Ernest Swinton in October 1914, was nourished and tended in infancy by Winston Churchill, then first lord of the Admiralty, and ultimately, after months of experiment hampered by official opposition, came to maturity in 1916 in the weapon known as the tank. Some of the British strategists, on the other hand, argued that instead of seeking a breakthrough on the Germans' impregnable Western Front, the Allies should turn the whole position of the Central Powers either by an offensive through the Balkans or even by a landing on Germany's Baltic coast. Joffre and his supporters won the argument, and the Balkan projects were relinquished in favour of a concentration of effort on the Western Front. But misgivings were not silenced, and a situation arose that revived the Middle Eastern scheme in a new if attenuated form. Early in January 1915 the Russians, threatened by the Turks in the Caucasus, appealed to the British for some relieving action against Turkey. The British, after acrimonious argument among themselves, decided in favour of a naval expedition in February to bombard and take the Gallipoli Peninsula (the western shore of the Dardanelles), with Constantinople as its objective. Though subsequently it was agreed that army troops might be provided to hold the shores if the fleet forced the Straits, the naval attack began on February 19 without army support. When at last Sir Ian Hamilton's troops from Egypt began to land on the Turkish shores, on April 25, the Turks and their German commander, Otto Liman von Sanders, had had ample time to prepare adequate fortifications, and the defending armies were now six times as large as when the campaign opened. Against resolute opposition from the local Turkish commander (Mustafa Kemal, the future Atatrk), Australian and New Zealand troops won a bridgehead at Anzac Cove, north of Kaba Tepe, on the Aegean side of the peninsula, with some 20,000 men landing in the first two days. The British, meanwhile, tried to land at five points around Cape Helles but established footholds only at three of them and then asked for reinforcements. Thereafter little progress was made, and the Turks took advantage of the British halt to bring into the peninsula as many troops as possible. The standstill of the enterprise led to a political crisis in London between Churchill, the Liberal government's first lord of the Admiralty, who, after earlier doubts, had made himself the foremost spokesman of the Dardanelles operation, and John, Lord Fisher, the first sea lord, who had always expressed doubts about it. Fisher demanded on May 14 that the operation be discontinued and, when he was overruled, resigned the next day. The Liberal government was replaced by a coalition, but Churchill, though relieved of his former post, remained in the War Council of the Cabinet. In July the British began sending five more divisions to the peninsula, and a new plan was hatched. In the hope of cutting the Turks' northsouth communications down the peninsula by seizing the Sari Bair heights, which commanded the Straits from the west, the British reinforced the bridgehead at Anzac Cove and, in the night of August 67, landed more troops at Suvla Bay (Anafarta Limani), farther to the north. Within a few days, both the offensive from Anzac and the new landing had proved ineffectual. More argument ensued in the War Council, and only late in the year was it acknowledged that the initially promising but ill-conducted enterprise should be given up. The evacuation of the troops was carried out from Suvla Bay and from Anzac Cove under cover of darkness in December 1915, and from the Cape Helles beaches in January 1916. The Dardanelles campaign thus came to a frustrating end. Had it succeeded it might well have ended Turkey's participation in the war. In failing, it had cost about 214,000 casualties and achieved nothing. The Western and Eastern fronts, 1915 The Western Front, 1915 Repeated French attacks in FebruaryMarch 1915 on the Germans' trench barrier in Champagne won only 500 yards (460 metres) of ground at a cost of 50,000 men. For the British, Sir Douglas Haig's 1st Army, between Armentires and Lens, tried a new experiment at Neuve-Chapelle on March 10, when its artillery opened an intense bombardment on a 2,000-yard front and then, after 35 minutes, lengthened its range, so that the attacking British infantry, behind the second screen of shells, could overrun the trenches ravaged by the first. But the experiment's immediate result was merely loss of life, both because shortage of munitions made the second barrage inadequate and because there was a five-hour delay in launching the infantry assault, against which the Germans, having overcome their initial surprise, had time to rally their resistance. It was clear to the Allies that this small-scale tactical experiment had missed success only by a narrow margin and that there was scope for its development. But the Allied commands missed the true lesson, which was that a surprise attack could be successfully made immediately following a short bombardment that compensated for its brevity by its intensity. Instead, they drew the superficial deduction that mere volume of shellfire was the key to reducing a trench line prior to an assault. Not until 1917 did they revert to the Neuve-Chapelle method. It was left to the Germans to profit from the experiment. In the meantime, a French offensive in April against the Germans' Saint-Mihiel salient, southeast of Verdun, sacrificed 64,000 men to no effect. The Germans, in accordance with Falkenhayn's strategy, remained generally on the defensive in the West. They did, however, launch an attack on the Allies' Ypres salient (where the French had in November 1914 taken the place of the British). There, on April 22, 1915, they used chlorine gas for the first time on the Western Front, but they made the mistake of discharging it from cylinders (which were dependent on a favourable wind) rather than lobbing it onto the enemy trenches in artillery shells. The gas did throw the agonized defenders into chaotic flight; but the German high command, having been disappointed by the new weapon's performance under adverse conditions in Poland earlier in the year, had failed to provide adequate reserves to exploit its unforeseen success. By the end of a month-long battle, the Allies' front was only slightly retracted. On May 9, meanwhile, the Allies had launched yet another premature offensive, combining a major French onslaught between Lens and Arras with two thrusts by Haig's 1st Army, from Festubert and from Fromelles, against the Aubers Ridge north of Lens. The French prolonged their effort until June 18, losing 102,000 men without securing any gain; the British, still short of shells against the Germans' mass of machine guns, had suspended their attacks three weeks earlier. An even worse military failure was the joint offensive launched by the Allies on Sept. 25, 1915. While 27 French divisions with 850 heavy guns attacked on a front 18 miles long in Champagne, north and east of Reims, simultaneous blows were delivered in distant Artois by 14 French divisions with 420 heavy guns on a 12-mile front south of Lens and by six British divisions with only 117 guns at Loos north of Lens. All of these attacks were disappointing failures, partly because they were preceded by prolonged bombardments that gave away any chance of surprise and allowed time for German reserves to be sent forward to close up the gaps that had been opened in the trench defenders' ranks by the artillery bombardment. At Loos the British use of chlorine gas was less effective than Haig had hoped, and his engagement of all his own available forces for his first assault came to nothing when his commander in chief, Sir John French, was too slow in sending up reserves; the French on both their fronts likewise lost, through lack of timely support, most of what they had won by their first attacks. In all, for a little ground, the Allies paid 242,000 men, against the defenders' loss of 141,000. Having subsequently complained bitterly about Sir John French's management of operations, Haig was appointed British commander in chief in his place in December.