A buddy gave me this little revolver to clean up for him. After gently removing the rust, I was able to make out the only text written on the gun. The top of the barrel says "Defiance" and under that is "Pat. April 23 1875".
The serial number is 2055. It is .22 caliber short and is a 7 shot.

Who made this revolver?

Whats it worth?