All attacks failed with enormous casualties in the face of French infantry and "mitrailleuse" firepower. Napoleon III showed personal interest in the mitrailleuse. Hence the weapon is usually known as the "Reffye mitrailleuse". Although it is derived from the French "mitrailleuse", its pronunciation is different. The first "mitrailleuse" was a manually fired 50-barrel volley gun. It was followed by the Belgian Montigny mitrailleuse in 1863. The Prussians and foreign observers were not impressed by the performance of the mitrailleuse. Most variants of the mitrailleuse were mounted on an artillery-style carriage. The battlefield use of the mitrailleuse as artillery was a fatally flawed concept. Montigny mitrailleuse guns were also imported from France. Other examples of effective mitrailleuse fire have also been described for the battle of Mars-la-Tour. Each mitrailleuse battery comprised six guns, each with a crew of six.