First World War flamethrowers. French soldiers (lower left) using insliquid fireins (an early form of flamethrower) in frontline trenches during the First World War (1914-1918). Many new weapons were developed during this war in an attempt to break the stalemate of trench warfare on the Western Front. Flamethrowers were first used by the Germans on 30 July 1915. The technology was quicky copied by the other combatants. Here, fuel is being sprayed out from a container on the back of the soldier. The fuel is ignited as it leaves the nozzle, producing the flames and smoke seen here. Photographed in 1916.