Mitrailleuse
The first "mitrailleuse" was a manually fired 50-barrel volley gun originally developed in Belgium in 1851 by the Belgian Army Captain Fafschamps, who made a rough prototype and drawings of his invention. The system was improved during the 1850s by Louis Christophe and the Belgian engineer Joseph Montigny, with the completion of the 37-barrel Montigny mitrailleuse in 1863. From 1859, Joseph Montigny proposed his design to Napoleon III, which led to the development of the French Reffye mitrailleuse, designed by Jean-Baptiste Verchère de Reffye with the collaboration of Montigny, and which was adopted by the French Army in 1865. Initially kept under wraps as a secret weapon, it was widely used in battle by French artillery during the Franco-Prussian War (1870–71). Smaller numbers of other designs, including the Gatling gun, were also purchased by the French government during the latter part of that conflict. The Reffye model had initially been built in small numbers and in secrecy: only about 200 were available at the beginning of the conflict. This also kept regular French field artillery in a neglected position in the eyes of French emperor Napoleon III, with dire consequences during the Franco-Prussian War of 1870–71.
Mitrailleuse
Several variants of the mitrailleuse concept were developed, with common elements to all of their designs. They were characterized by a number of rifled barrels clustered together and mounted on a conventional artillery chassis or (in the case of one model) a tripod. The ammunition was secured in a single block and placed into the breech, behind the open ends of the barrels. All of the barrels were loaded simultaneously by a manual closing lever or large horizontal screw. A second lever could be worked rapidly (or in some models, a crank could be turned) to fire each barrel in succession. This earned the weapon its French nickname of "moulin à café" (coffee grinder). (A very similar name was earned by the hand-cranked, mechanically loaded, continuous-firing, "coffee mill gun" in America during the American Civil War.)