+------------------+----------------+----------------+------------------+ | Chinese. | Arab. | English. | English. | | 13th Century. | 13th Century. | 17th Century. | 20th Century. | +------------------+----------------+----------------+------------------+ | Cord soaked | Cord of cotton | “Cottonweeke | “Cottonwick | | in a mixture | and palm | dipped | boiled in | | of sulphur and | leaves soaked | in gunpowder | a solution of | | water (and well | in naphtha and | wet with water”| mealed powder | | dried).[590] | dried.[591] | and dried.[592]| and gum, and | | | | | afterwards | | | | | dusted over | | | | | with mealed | | | | | powder before | | | | | it is dry.[593] | +------------------+----------------+----------------+------------------+ _Tubes._ Priming powder was ultimately replaced by small tubes, full of combustible matter, which fitted into the vents of guns. Of the multitude of these tubes only a few can be mentioned here. Tubes filled with quickmatch, and primed with mealed powder and spirits of wine, are said to have been in use in the first half of the eighteenth century.[594] In 1778 Captain Sir Charles Douglas, R.N., invented the gun-flint-lock. It was simply a flint-and-steel apparatus, fastened to the ventplate of the gun and worked by a lanyard, which ignited a tube placed in the vent. Captain Douglas introduced this lock into his ship, the _Duke_, at his own expense, and it worked so well that it was officially adopted for the Navy in 1790.[595] It was owing, apparently, to the personal intervention of General Sir Alexander Dickson that this lock was at length adopted for the Artillery in 1820.[596] In a letter to Sir Howard Douglas (son of Sir Charles), 18th April 1818, Sir Alexander gives his reasons for advocating the change:—“By the employment of slow match only, the fire is frequently retarded, and nothing can be more dangerous than lighted portfires in a battery ... I have ever prevented, as much as in my power, the use of portfires.”[597] A percussion tube, invented by Mr. Marsh, of the Royal Arsenal Surgery, was approved for the Navy in 1831: the Artillery was not supplied with a similar tube until 1846. In 1841 Lieutenant Siemens, of the Hanoverian Army, laid a friction tube before the officials of Woolwich Arsenal, which was tried and, owing to whatever defects, was rejected. Just ten years later Mr. Tozer, of the Royal Laboratory, made the copper friction tube now in use. It was officially adopted in 1853.[598]