In ancient times various devices were adopted to ignite the charge. Small guns were fired by priming powder poured down the touch hole (or vent) and ignited by glowing embers or a red-hot iron rod. Later the priming powder was ignited by a piece of slow match held in a linstock (a stick with a clamp at one end). About 1700, this was effected by means of a port-fire. This was a paper case about 16 inch (406 mm) long filled with slow-burning composition which burnt rather more than one inch (25 mm) per minute. Later again the charge was exploded by paper tubes (sometimes called Dutch tubes) filled with powder and placed in the vent and ignited by a port-fire. Friction primers (sometimes called "friction tubes") were used in the later black powder era, while in the latest patterns percussion or electric tubes are employed.