The pinfire cartridge was a popular development in Europe in the mid-1800s that never saw much exposure in the United States. A huge variety of pinfire revolvers were made by a myriad of large and small shops, with Liege Belgium being one of the biggest manufacturing centers.
Guns ranged from tiny folding-trigger 5mm models to massive 12mm weapons, with capacities from 5 to 20 shots. This particular one is both mechanically and visually interesting. It is a twin-barrel example, with a 20-round cylinder using chamber in two concentric rings. The inner ring of ten rounds are fired from the lower barrel and the outer ring of 10 rounds are shot through the top barrel. As one cocks and fires, the gun automatically alternates between the two. It is a clever way to get a large capacity without the cylinder become too ridiculously huge. Visually, of course, this revolver is pretty arresting, with its complete coverage of decorative gold embellishing and fancy case.