Cornophone

The Cornophone is basically a very long trumpet, shortened by folding the pipe back onto itself. It has a bell and flare, and valves, which are used to change the length of the pipe.

Its tonal range is between that of the trumpet and French horn.

The Cornophone (originally called "Cornon") was invented by Fontaine-Besson (Paris) in the 1880s.

Source:
http://de.wikipedia.org/wiki/Cornophone