<P> German troops carried 5,730 gas cylinders, weighing 90 pounds (41 kg) each, to the front by hand . The cylinders, opened by hand, relied on the prevailing wind to carry the gas towards enemy lines . Because of this method of dispersal, a large number of German soldiers were injured or killed while carrying out the attack . </P> <P> The French troops in the path of the gas cloud sustained about 6,000 casualties . Many died within ten minutes (primarily from asphyxia and tissue damage in the lungs), and many more were blinded . Chlorine gas forms hypochlorous acid when combined with water, destroying moist tissue such as the lungs and eyes . The chlorine gas, denser than air, quickly filled the trenches and forced the troops out into heavy enemy fire . </P> <P> Anthony R. Hossack of the Queen Victoria's Rifles described the chaos as the French Colonial Corps troops fled from the gas, </P> <P> Plainly something terrible was happening . What was it? Officers, and Staff officers too, stood gazing at the scene, awestruck and dumbfounded; for in the northerly breeze there came a pungent nauseating smell that tickled the throat and made our eyes smart . The horses and men were still pouring down the road . two or three men on a horse, I saw, while over the fields streamed mobs of infantry, the dusky warriors of French Africa; away went their rifles, equipment, even their tunics that they might run the faster . One man came stumbling through our lines . An officer of ours held him up with levelled revolver, "What's the matter, you bloody lot of cowards?" says he . The Zouave was frothing at the mouth, his eyes started from their sockets, and he fell writhing at the officer's feet . </P>

Who fought in the second battle of ypres