What is the brass instrument on Harry Stone by John Tams?

Its called the sousaphone, it is essentially a tuba that wraps around the player to reduce the difficulty of marching while playing it.

Brass instruments are instruments whose sound is made by vibration of air in a tube-like resonator in sympathy with the vibration of the player's lips. They are brassy and metallic in color. The...

French horn, trumpet, tuba, bar-sax (also part woodwind), baritone, euphonium (like baritone, but with straight top).

Brass instruments (Generally speaking) are easily distinguishable in that they generally look "brassy" ie they are made of metal. Examples include trumpets, trombones, french horns, tubas. An...

brass instruments are made out of metal and the have reeds and most of them have valves