Second Battle of Ypres The Second Battle of Ypres was a First World War battle fought for control of the strategic Flemish town of Ypres in western Belgium in the spring of 1915 , following the First Battle of Ypres the previous autumn . It marked the first time that Germany used poison gas on a large scale on the Western Front . Additionally , the battle was the first time that a former colonial force ( the 1st Canadian Division ) defeated a major European power ( the German Empire ) on European soil , in the Battle of St . Julien - Kitcheners ' Wood . Overview . The Second Battle of Ypres consisted of six separate engagements : The scene of the battles was the Ypres salient on the Western Front , where the Allied line which followed the canal bulged eastward around the town of Ypres , Belgium . North of the salient were the Belgians ; covering the northern part of the salient itself were two French divisions ( one Metropolitan and one Algerian ) The eastern part of the salient was defended by one Canadian division and two UK divisions . In total during the battles , the British Commonwealth forces were the II and V Corps of the Second Army made up of the 1st , 2nd and 3rd Cavalry divisions , and the 4th , 27th , 28th , 50th , Lahore and 1st Canadian Division s . Battle of Gravenstafel ( 22 – 23 April 1915 ) . Today this tiny hamlet is named s ' Graventafel . Gas attack on Gravenstafel . At around 5 : 00 pm on 22 April 1915 , the German Army released one hundred and sixty - eight tons of chlorine gas over a front on the part of the line held by French Territorial and colonial Moroccan and Algerian troops of the French 45th and 78th divisions . While this is often recognized as the first use of chemical warfare , poison gases were used at several earlier battles , including the Battle of Bolimov three months earlier . ( However this is known as the first successful use of poison gas as the gas used in the Battle of Bolimov liquified in the cold environment and was rendered harmless . ) The attack involved a massive logistical effort , as German troops hauled 5 , 730 cylinders of chlorine gas , weighing each , to the front by hand . The German soldiers also opened the cylinders by hand , relying on the prevailing winds to carry the gas towards enemy lines . Because of this method of dispersal , a large number of German soldiers were injured or killed in the process of carrying out the attack . Approximately 6 , 000 French and colonial troops died within ten minutes at Ypres , primarily from asphyxiation and subsequent tissue damage in the lungs . Many more were blinded . Chlorine gas forms hypochlorous acid when combined with water , destroying moist tissues such as lungs and eyes . The chlorine gas , being denser than air , quickly filled the trenches , forcing the troops to climb out into heavy enemy fire . With the survivors abandoning their positions en masse , a gap was left in the front line . However , the German High Command had not foreseen the effectiveness of their new weapon , and so had not put any reserves ready in the area . German troops started to enter the gap at 5 : 00 pm in some numbers , but with the coming of darkness and the lack of follow up troops the German forces did not exploit the gap , and Canadian troops were able to put in a hasty defence by urinating into cloths and putting them to their faces to counter the effects of the gas . Canadians held that part of the line against further attacks until 3 May 1915 at a cost of 6 , 000 wounded or dead . Casualties were especially heavy for the 13th Battalion of the CEF , which was enveloped on three sides and over - extended by the demands of securing its left flank once the Algerian Division had broken . One thousand of these " original " troops were killed and 4 , 975 were wounded from an initial strength of 10 , 000 . At Kitcheners ' Wood , the 10th Battalion of the 2nd Canadian Brigade was ordered to counter - attack into the gap created by the gas attack . They formed up after 11 : 00 pm on the night of 22 April with the 16th Battalion ( Canadian Scottish ) of the 3rd Brigade arriving as they were forming , tasked to support the advance . Both battalions stepped off with over 800 men , formed up in waves of two companies each , at 11 : 46 pm . Without prior reconnaissance , the battalions ran into obstacles half way to the objective and drew heavy automatic weapons fire from the Wood , prompting an impromptu bayonet charge . Their attack cleared the former oak plantation of Germans , at the cost of 75 percent casualties . The Canadian actions during the Battle of Gravenstafel are commemorated with the Saint Julien Memorial in the village of Saint Julien . Battle of St Julien ( 24 April – 5 May ) . Today this is known as Saint Juliaan . The village of St . Julien had been comfortably in the rear of the 1st Canadian Division until the poison gas attack of 22 April , whereupon it became the front line . Some of the first fighting in the village involved a hasty stop , which included the stand of Lance Corporal Frederick Fisher of the 13th Battalion CEF ' s machine - gun detachment ; who twice went out with a handful of men and a Colt Machine - gun and prevented advancing German troops from passing through St . Julien into the rear of the Canadian front line . Fisher was awarded the VC for his actions on the 22nd , but was killed when he attempted to repeat his actions on the 23 ; this was the first of 70 Canadian VCs awarded in the First World War . On the morning of 24 April 1915 the Germans released another cloud of chlorine gas , this time directly towards the re - formed Canadian lines just west of the village of St . Julien . On seeing the approach of the greenish - grey gas cloud , word was passed among the Canadian troops to urinate on their handkerchiefs and place these over their noses and mouths . However , the countermeasures were ineffective and the Canadian lines broke as a result of the attack , allowing German troops to take the village . The following day the York and Durham Brigade units of the Northumberland Division counterattacked failing to secure their objectives but establishing a new line close to the village . The third day the Northumberland Brigade attacked again , briefly taking part of the village but forced back with the loss of more than 1 , 900 men and 40 officers – two thirds of its strength . The 2nd Royal Dublin Fusiliers Battalion suffered heavily , incurring hundreds of casualties and with no respite took part in the next two subsidiary battles at Frezenberg and Bellewaarde . On 24 May the battalion was subject to a German chlorine gas attack near Saint Julien and effectively disintegrated as a fighting unit . The German Army first used chlorine gas cylinders in April 1915 against the French Army at Ypres . French soldiers reported seeing yellow - green clouds drifting slowly towards the Allied trenches . They also noticed its distinctive smell which was like a mixture of pineapple and pepper . At first the French officers assumed that the German infantry were advancing behind a smoke screen and orders were given to prepare for an armed attack . When the gas arrived at the Allied front - trenches soldiers began to complain about pains in the chests and a burning sensation in their throats . Most soldiers now realised they were being gassed and many ran as fast as they could away from the scene . An hour after the attack had started there was a four - mile gap in the Allied line . As the German soldiers were concerned about what the chlorine gas would do to them , they hesitated about moving forward in large numbers . This delayed attack enabled Canadian and British troops to retake the position before the Germans burst through the gap that the chlorine gas had created . Chlorine gas destroyed the respiratory organs of its victims and this led to a slow death by asphyxiation . One nurse described the death of one soldier who had been in the trenches during a chlorine gas attack . " He was sitting on the bed , fighting for breath , his lips plum coloured . He was a magnificent young Canadian past all hope in the asphyxia of chlorine . I shall never forget the look in his eyes as he turned to me and gasped : I can ’ t die ! Is it possible that nothing can be done for me ? " It was a horrible death , but as hard as they tried , doctors were unable to find a way of successfully treating chlorine gas poisoning . It was important to have the right weather conditions before a gas attack could be made . When the British Army launched a gas attack at the Battle of Loos on 25 September in 1915 , the wind blew it back into the faces of the advancing troops . This problem was solved in 1916 when gas shells were produced for use with heavy artillery . This increased the army ' s range of attack and helped to protect their own troops when weather conditions were not completely ideal . After the first German chlorine gas attacks , Allied troops were supplied with masks of cotton pads that had been soaked in urine . It was found that the ammonia in the pad neutralized the chlorine . These pads were held over the face until the soldiers could escape from the poisonous fumes . Other soldiers preferred to use handkerchiefs , a sock , a flannel body - belt , dampened with a solution of bicarbonate of soda , and tied across the mouth and nose until the gas passed over . Soldiers found it difficult to fight like this and attempts were made to develop a better means of protecting men against gas attacks . By July 1915 soldiers were given efficient gas masks and anti - asphyxiation respirators . One disadvantage for the side that launched chlorine gas attacks was that it made the victim cough and therefore limited his intake of the poison . Both sides found that phosgene was more effective than chlorine . Only a small amount was needed to make it impossible for the soldier to keep fighting . It also killed its victim within 48 hours of the attack . Advancing armies also used a mixture of chlorine and phosgene called ' white star ' . Private W . Hay of the Royal Scots arrived in Ypres just after the chlorine gas attack on 22 April 1915 . Battle of Frezenberg ( 8 – 13 May ) . The Germans had moved their artillery forward and put three Army corps opposite the 27th and 28th divisions on the Frezenberg ridge . The battle began on 8 May with a bombardment that disrupted the 83rd Brigade holding trenches on the forward side of the ridge but the first and second assaults by German infantry were repelled by the survivors . The third German assault of the morning pushed the defenders back . While the neighbouring 80th Brigade stopped the advance , the 84th Brigade was broken giving a two mile gap in the line . Further advance was stopped through counterattacks and a night move by the 10th Brigade . The picture in the top right of this article depicts the lone Canadian battalion in the British Expeditionary Force — Princess Patricia ' s Canadian Light Infantry as they fought to halt the German attack on Frezenberg . The original mural hangs in the Senate of the main Parliament Building in Ottawa , Ontario , Canada . In the battle , 2 / 3 of the regiment were either killed or wounded and only two officers were not killed or wounded in the battle . By the end of the battle , the regiment was being commanded by a lieutenant . After the chlorine gas attack at Ypres in 1915 , Sir John French , commander of the British Expeditionary Force , explained what happened . Battle of Bellewaarde ( 24 – 25 May ) . On 24 May the Germans released a gas attack on a 7 km front . British troops were able to defend against initial German attacks but eventually they were forced to retreat to the north and south . Failed British counterattacks forced a British retreat 1000 m northwards . Upon the end of the battle the Ypres salient was 5 km deep . Aftermath . By the end of the battle the size of the Ypres Salient had been reduced such that Ypres itself was closer to the line . In time it would be reduced by shelling until virtually nothing would remain standing . The surprise use of poison gas was not a historical first ( poison gas had already been used on the Eastern Front ) but did come as a tactical surprise to the Allies . After Second Ypres , both sides developed more sophisticated gas weapons , and countermeasures , and never again was the use of gas either a surprise , nor especially effective . The British quickly developed their own gas attacks using them for the first time at the Battle of Loos in late September . Development of gas protection was instituted and the first examples of the PH helmet issued in July 1915 . The Canadian Division was forced to absorb several thousand replacements shortly afterwards , but presented a most favourable image to their allies and the world . Another Canadian division joined the British Expeditionary Force in late 1915 , joined eventually by two more in 1916 . The battle also blooded many commanders , singling out some for praise , such as brigade commander Arthur Currie , and others for criticism , such as Garnet Hughes . The inadequacies of training and doctrine in the early CEF was made obvious by the antique tactics used at Kitcheners ' Wood and St . Julien , though tactics in the British Colonial armies would be slow to evolve . At Second Ypres , the smallest tactical unit in the infantry was a company ; by 1917 it would be the section . The Canadians were employed offensively later in 1915 , but not successfully . A Third Battle of Ypres , more commonly known as the Battle of Passchendaele was fought in the autumn of 1917 . The battle was marked by Canadian tactical successes as a result of many innovations in organization , training and tactics in both the infantry and artillery . Canadian honour . It was during the Second Battle of Ypres that Lieutenant Colonel John Alexander McCrae M . D . of Guelph , Ontario , Canada wrote the memorable poem " In Flanders Fields " in the voice of those who perished in the war . Published in Punch Magazine 8 December 1915 , it is still recited today , especially on Remembrance Day and Memorial Day . Lance Sergeant Elmer Cotton , described the effects of chlorine gas in 1915 .