Marcus J. Whitmore (1819-1881) was a gunmaker in Potsdam, New York, and worked at the Wagon & Gun Shop. He was one of the men listed on a breech loading patent in 1860 and also received a patent for a "clock, calendar." Many of Whitmore's surviving firearms utilize the swivel breech mechanism and have long metal actions like this example. Most, however, are over/under combination guns, but this unusual mid-19th century firearm has four barrels. Three are .40 caliber and rifled, and one is .410 caliber smoothbore. The paired rifle barrels share a blade front sight and adjustable notch rear sight, and the other rifled barrel and smoothbore barrel have individual sets of sights. There is clever trap compartment in between the barrels that contains a wooden ramrod. All four barrels and the left side of the action at the wrist are stamped with "M. J. WHITMORE/POTSDAM N.Y." The barrels have floral engraving patterns, and the action has additional floral engraving as well as a landscape scene with a log cabin and lake and a stand of American flags to the rear on the right and another lake scene with a steamboat on the left. The stock has numerous engraved German silver inlays, including a reposed stag flanked by Indian and American hunters on the left with pairs of waterfowl below, a cabin scene with a waterfall on the patch/capbox door, another reposed stag as the finial, a sun, and stars. There is also a small compartment ahead of the toe plate that could be used to carry a spare nipple or a few caps. The engraving and stock inlays are similar to known Whitmore rifles manufactured in Massachusetts by Nathaniel and Nathaniel Gilbert Whitmore and pictured in the article "My Magnificent Whitmore" by David Wood, Jr. suggesting a family connection. N. G. Whitmore was the master armorer at Springfield Armory and also manufactured a percussion rifle for General Ulysses S. Grant that was displayed at the Smithsonian.