This is a duplex instrument designed by Josef Josefovich Schediwa. Josef Schediwa (1853-1915) initially worked for Cerveny, but moved to The Ukraine about 1881, where he established his own firm in Odessa. He  patented this design  in 1901 and took out a subsequent patent [No. 8733] in 1902 for Bohland & Fuchs in Graslitz. He also invented a similarly shaped Lyrophone, but the schediphons were among his last inventions. 

In addition to the 4 valves a fifth valve operated by the left hand selects the smaller  bell - producing  a trombone sound from the cylindrical tubing versus a more mellow sound from the larger conical bore of the euphonium side of the instrument.    This rare instrument is a recent addition to the brass collection of my Brass Buddy, Ron Fabec,  of Sarasota Florida. He plans to totally restore it in due course.

Ron has since found the whole family of Scheidiphones on display at the National Museum of Czech Music in Prague!!  Scroll down for a photo of the whole family - including a Double Tuba!!!