Gas-operation is a system of operation used to provide energy to operate locked breech, autoloading firearms. In gas-operation, a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to dispose of the spent case and insert a new cartridge into the chamber. Energy from the gas is harnessed through either a port in the barrel or a trap at the muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and locking of the action. The first mention of using a gas piston in a single-shot breech-loading rifle comes from 1856, by the German Edward Lindner who patented his invention in the United States and Britain. In 1866, Englishman William Curtis filed the first patent on a gas-operated repeating rifle, but subsequently failed to develop that idea further. Between 1883 and 1885, Hiram Maxim filed a number of patents on blowback-, recoil-, and gas-operation. In 1885, one year after Maxim's first gas-operated patent, a British inventor called Richard Paulson, who a year before had patented a straight blowback-operated rifle and pistol, again, one year after Maxim’s first blowback patent, patented a gas piston-operated rifle and pistol which he claimed could be used with sliding, rotating or falling bolts. He would also patent a gas-operated revolver in 1886. Paulson did construct models of his rifle and tried them in France shortly after filing his patent. Furthermore, according to A. W. F. Taylerson, a firearms historian, his patented revolver was probably workable. In 1886 a gas-operated conversion of the Italian Vetterli bolt-action rifle was produced by the Italian Amerigo Cei-Rigotti which he also claimed could be adapted to other bolt-action magazine rifles.