Poison gas was used by both sides with devastating results (well, sometimes) during the Great War. The Germans pioneered the large-scale use of chemical weapons with a gas attack on Russian positions on January 31, 1915, during the Battle of Bolimov, but low temperatures froze the poison (xylyl bromide) in the shells. The first successful use of chemical weapons occurred on April 22, 1915, near Ypres, when the Germans sprayed chlorine gas from large cylinders towards trenches held by French colonial troops. The defenders fled, but typically for the First World War, this didn’t yield a decisive result: the Germans were slow to follow up with infantry attacks, the gas dissipated, and the Allied defenses were restored. Before long, of course, the Allies were using poison gas too, and over the course of the war both sides resorted to increasingly insidious compounds to beat gas masks, another new invention; thus the overall result was a huge increase in misery for not much change in the strategic situation (a recurring theme of the war).