This is a very early Besson 5 valve Euphonium, discovered as wall art.
Remarkably, this horn plays very nicely, and has not been restored. Compression is good, and it has a very sweet sound, very different to a modern Euphonium. It is fascinated to hear what these instruments sounded like early on in their development.
The 5th valve lowers the pitch by slightly more than one semi-tone, and when used in conjunction with lower pedal notes, it corrects intonation nicely.
The engraving mentions "Chicago Bore", indicating it was part of an early attempt to break into the USA market.
There appear to be four significant attempts to solve the issue of intonation in brass instruments, caused by the fact that the difference in pipe length required to change the pitch by a semi tone is different for high notes and low notes. This was the first - an additional valve designed specifically for use on low notes to make up for the insufficient pipe length in the other valves down low. The other attempts would be the Enharmonic system, Blaikley system, and triggers.
Serial number is 58xxx.
Record indicate this instrument was manufactured in 1896.