The serpentin is adjusted on a pivot through the stock, and forms a lever for the fingers beyond it. Then, holding a match, it is brought into contact with a slow match in a holder on the barrel and ignited; then by raising the lever, it is forced into the flashpan and touch-hole, where the priming is placed, and the gun discharged. This movement is in three varieties: the earliest moves towards the pan from the stock, while later it was fixed in the opposite direction; in the third it is propelled by a snap. First manipulated by the hand, then with a lever, and afterwards by a crank in connection with the trigger. The idea of the serpentin goes back to the fourteenth century, for the Froissart preserved in the town library at Breslau shows a drawing of a hand-bombard with an elementary form of triggered serpentin; and the same adjustment occurs in representations of these primitive weapons on a drawing preserved in the Hofbibliothek at Vienna. The mainspring was a further simplification of procedure in lending a more direct action to the serpentin, which fell with greater force, and obviated the necessity for blowing on the match. The harquebus was of several kinds and sizes, some fired from a rest, others from the shoulder or breast. There was also the heavy semi-portable weapon already referred to, served by three or four men; used both for field and fortress work. The length of the hand harquebus ranged from two and a half feet and upwards; barrels are both muzzle and breech-loaders; bores are of various sizes, sometimes very wide and bell-mouthed. The great disadvantage of the matchlock was the trouble and uncertainty experienced in retaining fire, and in it being necessary always to have a lighted match, or means of striking a light. This was especially felt in the chase, and the wheel-lock, which is said to have been invented by Johann Kiefuss of Nuremberg, in 1517, provided a much needed improvement on the older method; there is, however, at least one earlier example of this lock with the date inscribed. It did not, however, displace the matchlock for war purposes, owing to the greater cheapness and simplicity of the latter, which continued in use up to the eighteenth century. There is an example of a regimental matchlock musket at the Rotunda, Woolwich, dating about 1700--barrel, 46 inches long; calibre, 0.540 inch; steel mounts. The main principle of the wheel-lock is to generate the spark which is to ignite the powder for firing the shot in a self-acting manner, in contradistinction to the principle of the matchlock, where the ignition was served by a match which required to be kept constantly burning.