‘All quiet on the Western Front’ was the German modus operandi for most of 1915, concentrating instead on trying to gain supremacy in the east. The Second Battle of Ypres was a rare exception, used by the Germans to test lethal chlorine gas for the first time on a battlefield; tear gas had been tried on the eastern front to little effect. Waiting for winds blowing towards the Allied trenches, 6,000 cylinders were released on 22 April, with devastating effect, clearing a 5-mile gap in the defensive line. The Germans, unprepared for the impact of the gas, did not have sufficient manpower to exploit the breach in the Allies’ defences. Within 24 hours the Allies rushed reserves in to replenish their numbers and implemented rudimentary measures to counter the gas, with soldiers holding urine soaked cloth against their faces to minimize its effects.