band and screw to the flattened side of the mouth-piece, whose other side is cut down, chisel shape, for convenience.  Its voice is rich, mellow, less reedy, and much fuller and more limpid than the voice of the oboe, which Berlioz tries to describe by analogy as “sweet-sour.”  It is very flexible, too, and has a range of over three and a half octaves.  Its high tones are sometimes shrieky, however, and the full beauty of the instrument is only disclosed when it sings in the middle register.  Every symphony and overture contains passages for the clarinet which serve to display its characteristics.  Clarinets are made of different sizes for different keys, the smallest being that in E-flat, with an unpleasantly piercing tone, whose use is confined to military bands.  There is also an alto clarinet and a bass clarinet (Plate VIII.).  The bell of the latter instrument is bent upward, pipe fashion, and its voice is peculiarly impressive and noble.  It is a favorite solo instrument in Liszt’s symphonic poems.

[Sidenote:  Lips and reeds.]

[Sidenote:  The brass instruments.]

[Sidenote:  Improvements in brass instruments.]

[Sidenote:  Valves and slides.]

The fundamental principle of the instruments last described is the production of tone by vibrating reeds.  In the instruments of the brass choir, the duty of the reeds is performed by the lips of the player.  Variety of tone in respect of quality is produced by variations in size, shape, and modifications in parts like the bell and mouth-piece.  The forte of the orchestra receives the bulk of its puissance from the brass instruments, which, nevertheless, can give voice to an extensive gamut of sentiments and feelings.  There is nothing more cheery and jocund than the flourishes of the horns, but also nothing more mild and soothing than the songs which sometimes they sing.  There is nothing more solemn and religious than the harmony of the trombones, while “the trumpet’s loud clangor” is the very voice of a war-like spirit.  All of these instruments have undergone important changes within the last few score years.  The classical composers, almost down to our own time, were restricted in the use of them because they were merely natural tubes, and their notes were limited to the notes which inflexible tubes can produce.  Within this century, however, they have all been transformed from imperfect diatonic instruments to perfect chromatic instruments; that is to say, every brass instrument which is in use now can give out all the semitones within its compass.  This has been accomplished through the agency of valves, by means of which differing lengths of the sonorous tube are brought within the command of the players.  In the case of the trombones an exceedingly venerable means of accomplishing the same end is applied.  The tube is in part made double, one part sliding over the other.  By moving his arm, the player lengthens