This is likely a Colt Model 1849 Pocket Revolver. Over 300,000 were produced between 1850 and 1873, making it Colt's bestselling percussion handgun of the 19th century. They became popular as a personal defense weapon on the frontier during the Gold Rush and were commonly carried as a private purchase sidearm during the Civil War. These .31 caliber cap-and-ball revolvers were effective at a limited range of about 25 yards.
