Battle of Gravenstafel Ridge (22–23 April 1915) Second Battle of Ypres

in hamlet of gravenstafel (50°53′28″n 2°58′44″e / 50.891°n 2.979°e / 50.891; 2.979) @ 5:00 p.m. on 22 april, german army released 168 long tons (171 t) of chlorine gas on 6.5 km (4.0 mi) front on line held french territorial , colonial moroccan , algerian troops of french 45th , 87th divisions. although poison gas had been used before, @ battle of bolimów 3 months earlier, gas had liquefied in cold , become inert.

german troops carried 5,730 gas cylinders, weighing 90 pounds (41 kg) each, front hand. cylinders, opened hand, relied on prevailing wind carry gas towards enemy lines. because of method of dispersal, large number of german soldiers injured or killed while carrying out attack.

the french troops in path of gas cloud sustained 6,000 casualties. many died within ten minutes (primarily asphyxia , tissue damage in lungs), , many more blinded. chlorine gas forms hypochlorous acid when combined water, destroying moist tissue such lungs , eyes. chlorine gas, denser air, filled trenches , forced troops out heavy enemy fire.

anthony r. hossack of queen victoria s rifles described chaos french colonial corps troops fled gas,

plainly terrible happening. it? officers, , staff officers too, stood gazing @ scene, awestruck , dumbfounded; in northerly breeze there came pungent nauseating smell tickled throat , made our eyes smart. horses , men still pouring down road. 2 or 3 men on horse, saw, while on fields streamed mobs of infantry, dusky warriors of french africa; away went rifles, equipment, tunics might run faster. 1 man came stumbling through our lines. officer of ours held him levelled revolver, s matter, bloody lot of cowards? says he. zouave frothing @ mouth, eyes started sockets, , fell writhing @ officer s feet.

a 4-mile (6.4 km) gap left in front line. german high command had not foreseen effectiveness of new weapon , available troops had been transferred russia, leaving few reserves in west. general von falkenhayn, chief of german general staff, had ordered attack limited effort german 4th army. german troops advanced @ 5:00 p.m., dusk, apprehension effect of gas , lack of reserves prevented germans exploiting gap more significantly. canadian troops defended flank of break-in urinating cloth , holding them faces counter effects of gas. casualties heavy 13th battalion of canadian expeditionary force (cef), enveloped on 3 sides , over-extended in securing left flank after algerian division broke.

at kitcheners wood, 10th battalion of 2nd canadian brigade ordered counter-attack in gap created gas attack. formed after 11:00 p.m. on 22 april, 16th battalion (canadian scottish) of 3rd brigade arriving support advance. both battalions attacked on 800 men, in waves of 2 companies each, @ 11:46 p.m. without reconnaissance, battalions ran obstacles halfway objective; engaged in small-arms fire wood, began impromptu bayonet charge. attack cleared former oak plantation of germans @ 75-percent casualty rate.

the germans set fire chemical product of sulphur chloride had placed in front of own trenches, causing thick yellow cloud blown towards trenches of french , belgians. cloud of smoke advanced yellow low wall, overcoming breathed in poisonous fumes. french unable see doing or happening. germans charged, driving bewildered french past own trenches. enveloped fumes not able see each other half yard apart. have seen of wounded overcome sulphur fumes, , progressing favourably. effect of sulphur appears temporary. after-effects seem bad swelling of eyes, sight not damaged.

dusk falling when german trenches in front of french line rose strange green cloud of death. light north-easterly breeze wafted toward them, , in moment death had them throat. 1 cannot blame them broke , fled. in gathering dark of awful night fought terror, running blindly in gas-cloud, , dropping breasts heaving in agony , slow poison of suffocation mantling dark faces. hundreds of them fell , died; others lay helpless, froth upon agonized lips , racked bodies powerfully sick, tearing nausea @ short intervals. die later – slow , lingering death of agony unspeakable. whole air tainted acrid smell of chlorine caught @ of men s throats , filled mouths metallic taste.