Per R. L. Wilson in "The Paterson Colt Book," approximately 500 of the No. 1 Pocket or "Baby Paterson" revolvers were manufactured in 1837 and 1838, and some cylinders were later rounded. This revolver is one of the examples later "improved" by John Ehlers c. 1840-1843 following the bankruptcy of Samuel Colt's Patent Arms Manufacturing Company. The diminutive "Baby Paterson" and Fourth Model Ehlers revolver are the smallest Colt percussion revolvers and almost appear to be scaled miniatures of the "Texas Paterson" revolvers used by the Texas Rangers. The Ehlers Model Paterson revolver is a rare variation of the rare and very desirable Colt Baby Paterson revolver. John Ehlers is believed to have manufactured and assembled approximately 500 Fourth and Fifth Model Ehlers revolvers utilizing components of the Colt Paterson acquired after the bankruptcy of the Colt Patent Arms Manufacturing Company. The Ehlers Model Paterson revolvers are key pieces in the development of the Colt percussion revolver. Many of the improvements seen on this variation were adopted for Colt's later percussion revolvers. This revolver has the distinctive Ehlers features which include an attached loading lever with a retaining spring, capping channel in the right side of the recoil shield, and rounded rear of the cylinder. The cylinder rotates using a pawl and ratchet mechanism rather than the cylinder turning ring found on early Colt Paterson revolvers. In addition, the top of the barrel is roll-stamped with "Patent Arms Paterson. N.J.-Colt's Pt." which eliminates the "M'g Co." marking found on Colt Paterson revolvers. The five-shot cylinder is roll-engraved with the "centaur scene" and the "COLT" four horsehead trademark. The serial number "310" is visible on the wedge, barrel lug, rear face of the cylinder, and on the frame below the arbor. The ebony grip has a beveled butt.