Offered here is a real treasure in American arms development: an automatic percussion revolver designed by Ralph Mershon and Jehu Hollingsworth and based on a Colt Model 1860 Army. Their design was assigned U.S. patent number 39,825 which was dated September 8, 1863 and referenced as an “improvement in self-cocking revolving fire arms.” Mershon and Hollingsworth had invented an automatic revolver that predated the well-known and first commercial automatic revolver the British Webley-Fosbery by a good three decades. Designed in the middle of the Civil War, an era that saw tremendous advances in weaponology, the Mershon & Hollingsworth self-cocking device was a precursor to semi-automatic handguns. If we consider that this revolver was the model used for patent submission and knowing that the revolver never made it into production, we confidently conclude that the revolver offered here is the only one in existence. At its heart the revolver is an extensively modified Colt Model 1860 Army, no. 3803, expertly fitted to the self-cocking device housed on a custom built brass frame ("3", "4", and "5" are visible on the left side around the aforementioned device). The self-cocking mechanism operated by a wind up clock type spring that engaged a notched ratchet tied internally to the hammer via a “hammer dog”. Once engaged the “hammer dog” acted like a sear. The spring, located on the right side of the frame, was easily wound by a folding handle mounted on the opposite side. A locking latch behind the hammer ensured that the hammer would not cock while the user wound the spring. “Automatic firing” worked when the trigger was pulled, allowing for the hammer to fall and strike a percussion cap. Releasing the trigger sent the hammer back to full cock while at the same time the cylinder unlocked, rotated and locked again. The spring housing is marked “MERSHON & HOLLINGSWORTH/SEPT 8TH 1863.” The top of the barrel has the one-line Colt New York address. The standard Colt factory Model 1860 naval scene is on the unnumbered rebated cylinder. The revolver was featured in J.B. Wood’s article “Mershon & Hollingsworth Self-Cocking Revolver” as seen on the "American Rifleman" website and published in the February 2012 issue of the American Rifleman. Prior to their self-cocking revolver design, Mershon and Hollingsworth developed an automatic rifle based on Colt’s Model 1855. Both the rifle and revolver incorporated the same clockwork type spring powered mechanism. Provenance: The Clive Cussler Collection