monplace as compared
with the trumpet, but because of its great agility in the rendition of
trills, repeated tones, etc., it is universally used in all sorts of
combinations, even (as noted above) taking the place of the trumpet in
many small orchestras.

[Illustration: CORNET. Length, 13-3/4 in.]

[Illustration: SLIDE TROMBONE. Length, 3 ft. 9 in. Range of tenor
trombone (the size ordinarily used) E to b-flat']

25. The pitch sounded by the _trombone_ is altered by lengthening or
shortening the tube of which the instrument is constructed, this being
possible because the lower part slides into the upper and can be pulled
out to increase the total length of the tube through which the air
passes. There are usually three _trombones_ in the orchestra, each
playing a separate part, and the combination of this trio (with the
_tuba_ reinforcing the bass part) is majestic and thrilling, being
powerful enough to dominate the entire orchestra in _Fortissimo_
passages. But the _trombones_ are useful in soft passages also, and
their tone when playing pianissimo is rich, serene, and sonorous.

26. The _bass tuba_ is a member of the saxhorn family[42] and supplies
the lowest part of the brass choir, as the double-bass does in the
string choir. It is used in both orchestra and band, being often
supported in the larger bands by a still lower-toned member of the same
family--the _contra-bass tuba_. The range of the _tuba_ is from
[Illustration: GG] to [Illustration: g'].

[Footnote 42: The _saxhorn_ was invented about 1840 by Adolphe Sax, a
Frenchman. The _saxophone_ is the invention of the same man.]

[Illustration: BASS TUBA. Length, 3 ft. 3 in.]

[Illustration: BASS DRUM. Diameter about 2-1/2 ft.]

[Illustration: CYMBALS. Diameter, 13-1/4 in.]

27. The _kettle-drum_ is the most important member of the percussion
family and is always used either in pairs or in threes. The size of
these instruments varies somewhat with the make, but when two drums are
used the diameter is approximately that given under the illustration.
The range of a pair of _drums_ is _one octave_ [Illustration: F f] and
when but two drums are used the larger one takes the tones from F to
about C of this range, and the smaller takes those from about B[flat]
to F. The most common usage is to tune one drum to the _tonic_, and the
other to _the dominant_ of the key in which the composition is written.
The pitch of the _kettle-drum_ can be varied by increasing