Early oil well. View of workers at an early oil well. In the foreground a male worker is pouring nitroglycerin into a metal cylinder. This was part of a process to unblock choked oil-wells. When filled the cylinder would be fitted with a detonator and lowered to rest in the borehole. A cast iron cylinder known as the 'go devil' would then be dropped into the borehole to activate the detonator and fire the nitroglycerin. This process was known as shooting. The worker responsible for this was known as the shooter.