5925276 ?Tommy?s smoke hat?, 1915 circa (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: ?Tommy?s smoke hat?, 1915 circa. Photograph, World War One, Home Front (1914-1918), 1915 circa. A soldier home on leave exhibits his PH Hood to an admiring crowd in Trafalgar Square. This device was one of the British Army?s first gas hoods. The introduction of gas warfare in 1915 had created an urgent need for protective equipment to counter its effects. A piece of gauze or cotton wadding, soaked in urine or bicarbonate of soda, provided some protection, but the British Army soon developed a range of gas helmets based on fabric bags and hoods that has been treated with anti-gas chemicals. Improvements continued to be made and by the middle of 1916 the small box filter respirator was in circulation. This design gave protection against the different gases in use. Despite this, during the war the British Empire suffered over 180,000 gas casualties. One of 193 British and Allied Official photographs.); by National Army Museum ; out of copyright.