diameter, altering its position by placing it nearer the mouthpiece.
These laws, which were likewise known to the Greeks and Romans,[8] had
to be rediscovered by experience in the 18th and 19th centuries,
during which the mechanism of the key system was repeatedly improved.
Due consideration having been given to these points, it will also be
necessary to remember that the stopping of the seven open holes leaves
only the two little fingers (the thumb of the right hand being in the
ordinary clarinet engaged in supporting the instrument) free at all
times for key service, the other fingers doing duty when momentarily
disengaged. The fingering of the clarinet is the most difficult of any
instrument in the orchestra, for it differs in all four octaves of its
compass. Once mastered, however, it is the same for all clarinets, the
music being always written in the key of C.

[Illustration: real sounds]

The actual tonality of the clarinet is determined by the diatonic
scale produced when, starting with keys untouched and finger and
thumb-holes closed, the fingers are raised one by one from the holes.
In the B flat clarinet, the _real sounds_ thus produced are being part
of the scale of B flat major. By the closing of two _open_ keys, the
lower E flat and D are added.

The following are the various sizes of clarinets with the key proper
to each:

E flat, a minor third above the C clarinet.
B flat, a tone below " "
The high F, 4 tones above " "
The D, 1 tone above " "
The low G, a fourth below " "
The A, a minor third below " "
The B# 1 semintone below " "
The alto clarinet in E flat, a fifth below the B flat clarinet.
The tenor or basset horn, in F, a fifth below the C clarinet.
The bass clarinet in B flat, an 8ve below that in B flat.
The pedal clarinet in B flat, an 8ve below the bass clarinet.
The clarinets in B flat and A are used in the orchestra; those in C
and E flat in military bands.

_History_.--Although the single beating-reed associated with the
instruments of the clarinet family has been traced in ancient Egypt, the
double reed, characteristic of the oboe family, being of simpler
construction, was probably of still greater antiquity. An ancient
Egyptian pipe found in a mummy-case and now preserved in the museum at
Turin was found to contain a beating-reed sunk