This selection of images focuses on gas as a weapon in the First World War. Both sides had to develop anti-gas protection for the troops and their animals. Early on, improvised nose plugs were used to help horses breathe during gas attacks. The earliest gas masks for soldiers were cotton hoods soaked in bicarbonate of soda, but by 1917 troops were issued with fitted masks with airtight seals and filters containing chemicals to neutralise the gas.
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