14th Battery Royal Australian Field Artillery, near Ypres, 1917. The sheer physical work required of the artillery was tremendous. To cover an attack with a creeping barrage, these 18-pounder guns would fire two to four shells (twenty-two pounds per round, including cartridge and propellant) per minute, for fifty minutes of each hour (the guns needed to cool and have the sights checked), for up to six hours. Each fuze had to be set by hand, and the elevation had to be adjusted as the gun and air temperatures changed, and depending on the batch of propellant involved.

Source: IWM photo E920.