Johnson & Bye Air Pistol
Johnson & Bye Air Pistol.
Commonly referred to as the Champion air pistol (See also 'Bedford Walker' entry).
Made by Iver Johnson and Martin Bye in about 1875-1883.
With thanks to Bruce for this pic.
From the top:
Nickelled & Japanned black versions solid metal grip
Nickelled & Japanned black versions with hard wood grips