BOMBARDON or BASS TUBA, the name given to the bass and contrabass of the brass wind in military bands, called in the orchestra bass tuba. The bombardon was the very first bass wind instrument fitted with valves and was the outcome of the appli cation of valves to the bugle family whereby the saxhorns were also produced. The radical difference between the saxhorns and the tubas (including the bombardon) is that the latter have a sufficiently wide conical bore to allow of the production of fun damental sounds in a rich, full quality of immense power. When the brass wind instruments with conical bore and cup-shaped mouthpiece first came into use, it was a well-understood principle that the tube of each instrument must theoretically be made twice as long as an organ pipe giving the same note ; for example, the French horn sounding the 8ft. C of an 8ft. organ pipe, must have a tube Oft. long. After the introduction of pistons, instrument makers experimenting with the bugle, which has a conical bore of very wide diameter in proportion to the length, found that bari tone and bass instruments constructed on the same principle gave out the fundamental full and clear. A new era in the construc tion of brass wind instruments was thus inaugurated. The bom bardons possess a chromatic compass of 31 to 4 octaves but the lowest notes produced by the valves are very difficult to obtain, for the lips seldom have sufficient power to set in vibration a column of air of such immense length, at a rate of vibration slow enough to synchronize with that of notes of such deep pitch.