A touch hole is a small hole, through which the propellant charge of a cannon or muzzleloading gun is ignited. In small arms, the flash from a charge of priming held in the flash pan is enough to ignite the charge within. In artillery, priming powder, a fuse, squib, or friction igniter is inserted into the touchhole to ensure ignition of the charge. If a cannon was in danger of being captured by the enemy, its crew would "spike" the gun to prevent it from being used against them. This would involve hammering a barbed steel spike into the touch-hole, which could only be removed with great difficulty.