Treble (a doublet of "triple," three-fold, from Lat. triplus, triple; cf. "double" from duplus), the term applied, in music, to the high or acute part of the musical system, as opposed to and distinguished from the "bass," the lower or grave part. The middle C is the practical division between the parts. The word is also used as equivalent to the "soprano" voice, the highest pitch or range of. the human voice, but generally it is confined to a boy's voice of this quality, "soprano" being used of the corresponding female voice. The treble-clef is the G-clef on the second line. The origin of this application of the term "treble," triplus, threefold, to the highest voice or part is due to the fact that in. the early plain-song the chief melody was given to the tenor, the second part to the alto (discantus) and where a third part (triplum) was added it was assigned to the highest voice, the soprano or treble.
TREBUCHET, a medieval siege engine, employed either to batter masonry or to throw projectiles over walls. It was developed from the post-classical Roman onager (wild ass), which derived its name from the kicking action of the machine. It consisted of a frame placed on the ground to which a vertical frame of solid timber was rigidly fixed at its front end; through the vertical frame ran an axle, which had a single stout spoke. On the extremity of the spoke was a cup to receive the projectile. In action the spoke was forced down, against the tension of twisted ropes or other springs, by a windlass, and then suddenly released. The spoke thus kicked the crosspiece of the vertical frame, and the projectile at its extreme end was shot forward. In the trebuchet the means of propulsion was a counter-weight. The axle which was near the top of a high strutted vertical frame served as the bridge of a balance, the shorter arm of which carried the counter-weight and the longer arm the carrier for the shot. An alternative name for the trebuchet is the mangonel (mangonneau).
