A World Undone: The Story of the Great War, 1914 to 1918

by G.J. Meyer

From now on all the armies of the Great War would expect gas and be more or less prepared for it. And though both sides would use it extensively, never again would it disable enough men to decide the outcome of a battle. Even at Ypres the British and French needed only hours to understand what they were faced with and find ways to deal with it. First it was noticed that the brass buttons on the soldiers’ uniforms had turned green. Someone deduced from this phenomenon that the mysterious cloud must be chlorine and knew of a quick preventive: by breathing through a cloth on which they had urinated (a spare sock, for example), the troops could neutralize the poison before it reached their lungs. The first improvised gas masks thus emerged almost immediately after the first use of chlorine.