What is this Antique Brass Instrument on display at the Musical Instrument Museum in Brussels, Belgium? - Music: Practice & Theory Stack Exchange

Does anyone know what type of instrument this is? It looks like some type of Euphonium, but obviously very different.

Various musical instrument hi-res stock photography and images - Page 5 - Alamy

Singing Bronze: A History of Carillon Music, PDF, Bronze

MIM MIM

MIM MIM

Musical Instrument Museum - Brussels, Belgium

Various musical instrument hi-res stock photography and images - Page 5 - Alamy

What is this Antique Brass Instrument on display at the Musical Instrument Museum in Brussels, Belgium? - Music: Practice & Theory Stack Exchange

Brussels and the Musical Instruments Museum (MIM) - Piano World Piano & Digital Piano Forums

Museum of keyboard instruments hi-res stock photography and images - Alamy

The Brussels Musical Instrument Museum has some of the rarest instruments from around the world in its collection