This is a rare example of a Colt factory cut-away Model 1851 Navy revolver that was manufactured in 1857. This revolver is part of a small group of Model 1851 Navy revolvers in the 68600 serial number range that Colt experts believe were manufactured by Colt for classroom instruction at the U.S. Military Academy at West Point, New York. Two "skeletonized" Model 1851 Navy revolvers were listed in the 1898 Catalog of the Ordnance Museum at West Point. The cut-away models were also used as salesmen's samples to demonstrate the mechanics of the revolver. Recent research has shown that the cut-away revolver was inspired by firearms appearing at the Great Exhibition of 1851. The most spectacular of the Model 1851 cutaways, like this example, have been found with brown finished barrels and cylinders. In "The Book of Colt Firearms," author R.L. Wilson estimates the total production of Model 1851 Navy factory cut-aways "as approximately two dozen" revolvers. Wilson's book pictures serial number 68686, which is two digits away from this revolver, serial number 68684 (page 127). For further reading see Nathan L. Swayze's book "'51 Colt Navies" (pages 233-235). In Swayze's book, Model 1851 cut-away revolvers with serial numbers 68687 and 68683 are pictured and described. This revolver, serial number 68684, is pictured and described in Robert Lee and R.L Wilson's book "The Art of the Gun: Magnificent Colts, Selections from the Robert M. Lee Collection, Vol. I" (pages 192-193). This revolver has a barrel that is marked "-ADDRESS SAML COLT NEW-YORK CITY-" on the top flat. The left side of the frame is marked "COLTS/PATENT." The cylinder is roll engraved with the Texas Navy battle scene and "COLTS PATENT No. 68684" with the serial number struck over a partially erased earlier number. The leading edge of the cylinder reads, "ENGAGED 16 MAY 1843." The full serial number "68684" is stamped on the barrel, frame, trigger guard, back strap and cylinder. The partial matching serial number "8684" is stamped on the loading lever, barrel wedge and arbor pin. The frame has extensive factory modifications to show the mechanical function of the components. The left recoil shield has been milled away, and eight cutouts on the left side of the frame expose the operation of the hand when the hammer is cocked. The upper left corner of the grip has been cut away to show the action of the hammer roller on the mainspring. A hole has been drilled through the right side of the frame and recoil shield to expose the rear portion of each cylinder stop. A portion of the frame has been milled away to expose the forward portion of the each cylinder stop. The lower portions of both sides of the frame have been milled away, and there are cutouts in the bottom of the trigger guard to show the function of the trigger. The bottom of the grip is stamped "J.R.H., Jr." inside an oval, which is the collector's mark of famed Colt collector John R. Hegeman, Jr. He was a pioneer in Colt collecting and had great connections within the Colt company that afforded him the opportunity to own many pre-production prototype and serial number 1 guns. As one Colt researcher put it, "He assembled the finest Colt collection known outside of the factory's own holdings." Many of his Colts ended up in some of the finest gun collections over the years. Wilson's conclusion on this known Hegeman collection piece: "The striking condition of this revolver suggest that, not unlike many of Hegeman's other guns, this revolver was obtained directly from the Colt company, at the Hartford factory site, on Huyshope Avenue." According to Wilson, this revolver is documented in Hegeman's own catalog, which describes the revolver in his own hand.