plain. The French army had not completed an adaptation to siege warfare and much of the equipment necessary, particularly heavy artillery, did not exist. It had been impossible to synchronise operations in Artois with the First Battle of Champagne, which ended on 17 March. Debate within the army as to means and ends had led to two schools of thought, those, like Joffre, who favoured "continuous battle" (an attack without pause involving all resources) and advocates of "methodical battle" like Foch, who wanted to conduct offensives as methodical series of attacks with pauses to reorganise and consolidate. The theoretical bases of the forthcoming French offensive in Artois were collected in (Purpose and Conditions for Comprehensive Offensive Action) 16 April 1915 (and Note 5779) which had been compiled from analyses of reports received from the front since 1914. The document contained instructions on infiltration tactics, "rolling" barrages and poison gas, which were to be used systematically for the first time. Although doubtful about the capacity of the British to attack, Joffre wanted an offensive on the northern flank of the Tenth Army, to force the Germans to disperse their defences. At a meeting on 29 March, with Sir John French, the commander of the British Expeditionary Force (BEF), and Herbert Kitchener, the Secretary of State for War, it was agreed that the IX Corps () and XX Corps would be relieved at Ypres by British units and on 1 April, French agreed to attack at the same time as the Tenth Army. French doubts about the efficiency of the BEF had not diminished after the Battle of Neuve Chapelle and British doubts about the French had increased after the at Ypres on 22 April, when French troops had been routed by a German gas attack; Joffre had to agree to place reserves behind the Ypres front to secure British co-operation. The number of divisions in the German Army was increased over the winter with large intakes of recruits and by reorganising square twelve-battalion divisions (in two brigades with two regiments each) into triangular divisions with one brigade headquarters commanding nine battalions in three regiments. The surplus regiments provided new divisions with a nucleus of trained and experienced troops; smaller divisions made it easier to move them from quiet sectors without undue disruption. On 3 March, Falkenhayn had formed the 11th Army, the (Breakthrough Army) to be the main attacking force on