Cleveland, Ohio
KING (The H.N. White Co.)

Brass & Mother-of-Pearl Valve Caps
ca.  late 1960s 
Bell Diameter: 8 in with .500 bore
Wind Instruments – Brasswinds – Trombones / Sackbuts

Engraved on bell: KING / TROMBONIUM / THE H.N. WHITE, CO. / CLEVELAND / OHIO
Serial Number: 422762

This trombonium was made by the King Musical Instruments, known and engraved on the bell as the H.N. White Company.  The Trombonium has the distinction of being the last instrument designed by Mr. White before he passed away.  They were made from 1938 to mid-1970s.  It is in the key of ‘F’ with a bell front design and a bell collar that allows the bell to be rotated.  The trombonium, unlike the trombone with its slide, has three valves, making it easier to hold and play.  According to the H.N. White website, “The King Trombonium had precisely the same tone as a slide trombone and will improve the marching section of any band.”  In addition, the trombonium has a third valve slide that can be changed from the top and bottom, to adjust pitch.  There is one water key, so due to the narrow bore of the mostly cylindrical tubing the trombonium is spun around like the French horn when emptying the fluid.

Resource:  http://www.hnwhite.com/Trombonium%20Page.htm  Also checkout Trent Hamilton to hear it played:  https://www.youtube.com/watch?v=A5tIpaRMMz8