This is certainly an extremely rare example of a "de Dartein" patent "propeller" revolver. The design of this revolver is illustrated and described in French patent number 87,672 dated November 2, 1869, granted to "de Dartein" for a "Propeller Revolver". U.S. patent number 102,872 has also been located relating to a similar designed revolver, dated May 10, 1870 and granted to inventors Charles Felix de Dartein and Jules Edouard de Dartein, of Strasbourg, France. Another British patent, number 778 dated March 16th, 1870, has also been located, as granted to agent Henry Woodcroft Hammond on behalf of the two de Dartein inventors. An example of a similar revolver, exactly like the kind illustrated in the referenced U.S. patent, was previously sold by Rock Island Auction Company, and was unidentified at the time (Auction 68, lot 1359). The action functions in a unique manner, and is built to a high quality standard. Cocking the firearm requires the operator to pull back with their trigger finger on a sliding cocking knob located ahead of the trigger. Pulling back on the cocking knob rotates the cylinder and cocks the striker type firing pin. The cylinder is rotated via helical fins or "propellers" that are actuated by the sliding cocking mechanism which has a bar with a helical camming slot, in which it also acts as a locking mechanism. It shares slight similarities in function to the Mauser "zig-zag" and Webley Fosbery revolvers that came after. Once cocked, the operator pulls the trigger to release the striker firing pin. The revolver utilizes a unique type of gas seal cartridge that has an oversized metallic casing with thick walls that completely surrounds a smaller diameter bullet projectile, acting as a gas seal where the cylinder meets the rear face of the barrel at the breech. The rear of the chamber is 11mm which tapers to 10mm whilst the saboted projectile is 9mm, the theory being the bullet would engage with the much small diameter forcing cone of the barrel. Whilst the unique ammunition is illustrated in the U.S. patent drawing, it is believed that no examples of the ammunition have survived. The right of the frame has a safety lever that when flipped to the downward position allows the cylinder to rotate without cocking the trigger, allowing for loading of the 5-shot cylinder at the rear, with an ejector rod located at the right. Octagon barrel, fixed dovetailed blade front sight with frame cut notch rear sight. The revolver is blue finished, with the maker's mark "A.M" (possibly for Auguste Malherbe of Liege) on the left of the chamber area, "5" on the right of the chamber area, "4" on the front and rear surfaces of the cylinder as well as on the loading gate, a circled "A.M" stamped on the left grip panel, and no visible proofmarks. Fitted with smooth walnut grip panels. Includes consignor supplied related research papers and scanned pages of the article "Le revolver a helices du capitaine de Dartein" from the April 2006 issue of "Gazette des armes" magazine.

Very good plus, retains strong traces of original blue finish in some protected areas with otherwise smooth brown patina, and some scattered light freckling. Grips are also very good with scattered dents and scratches, and a defined stamp on the left. Mechanically functions fine, although ejector rod sometimes interferes with cylinder rotation due to a detent missing from the rear of the ejector housing. An extremely rare and interesting revolver that would make a very fine addition to any advanced early military arms collection! Writer does not recall another example in recent times!