The Second Battle of Ypres — The Use of Gas in War
On 22 April 1915 the German army launched its only major offensive on the western front for 1915. To distract from the major offensive launched simultaneously on the eastern front (see Map 19), four divisions struck against the Canadian and French troops holding the northern flank of the Ypres salient. A new weapon supplemented the usual artillery bombardment — chlorine gas released from cylinders to float across the enemy’s trenches. Although not the first use of gas — both French and German armies had previously used tear-gas shells, with limited effect — the Ypres attack was the first occasion in which poison gas had a real tactical impact on the battlefield. It initiated a new era of industrialised warfare.