This pair of pistols appears to be the exact pair pictured and discussed in the paper "Automatic Priming of Flintlock and Percussion Firearms" by Henry M. Stewart Jr. available through the American Society of Arms Collectors. The author identified them as manufactured in the middle of the 18th century, and other sources confirm I. Glass was active in London from 1720 to 1779 and was particularly known for his repeating pistols. As Stewart notes, these pistols are operated by rotating the levers on their left sides forward towards the muzzle (with the muzzle pointed towards the ground) and then pulling the lever back to the rear. As the lever rotates forward, a ball is loaded in the chamber, and then, as the lever travels rearward, powder is dropping in behind the ball, the cock is set, the pan is primed and closed, and the pistol is readied for use. The powder and balls are stored in a compartment on the left side allowing for much more rapid fire than standard muzzle loading pistols of the era. The machining in the mechanism had to have incredibly tight tolerances to prevent gas from leaking back into the powder reservoir; if a leak occurred, the pistol could explode grievously injuring or even killing the user. The barrels are four-stage cannon style with rifling, and the octagonal breech sections are engraved on each flat with dot and scrolls bands. The action body is engraved overall with scrollwork (much rubbed). The varnished walnut grips are mounted with hallmarked silver escutcheon plates and hallmarked elaborate silver butt-caps (Standard silver mark, Birmingham City mark, CF (Charles Freeth), no date letter). Charles Freeth was a Birmingham silversmith and well-known maker of silver mounts for pistols of this period. The Michele Lorenzoni and Domenico (name also given as Giacomo) Berselli system is often called the Cookson System given the prevalence of guns of this type from that maker, though guns by Mortimer and others are also known. Guns of this design are all scarce.

See description in A.