There are two kinds of percussion: the first kind comprises instruments of fixed and musically recognisable pitch; the second comprises those whose less musical sounds can only be classed as noises designed for special effect or for rhythmic colour. Timpani, bells, glockenspiel, keyboard harmonica and the little antique cymbals have fixed pitch. The bass drum, tenor drum, side drum, tambourine, ordinary cymbals, tamtam, triangle and Turkish crescent are in the other category and just make noises of different types.

THE TIMPANI

Of all percussion instruments I regard the timpani as the most precious, or at least the one most widely in use, exploited by modern composers for the widest range of picturesque and dramatic effects. Early composers scarcely used them except to strike the tonic and dominant in a rather vulgar rhythm in pieces which strove for brilliance or for a warlike effect. They were thus almost always paired with trumpets.

In most orchestras there are still no more than two timpani, with the larger one assigned to the lower note. They are customarily given the tonic and dominant notes of the key in which the piece is written. Not many years ago composers used invariably to write G and c on the bass clef for the timpani, with a simple indication at the beginning of the actual pitches these notes should represent.