"Perfect intonation is a great problem--one practically unknown to the
average amateur quartet player. Four players may each one of them be
playing in tune, in pitch; yet their chords may not be truly in tune,
because of the individual bias--a trifle sharp, a trifle flat--in
interpreting pitch. This individual bias may be caused by the attraction
existing between certain notes, by differences of register and _timbre_,
or any number of other reasons--too many to recount. The true beauty of
the quartet tone cannot be obtained unless there is an exact adjustment,
a tempering of the individual pitch of each instrument, till perfect
accordance exists. This is far more difficult and complicated than one
might at first believe. For example, let us take one of the simplest
violin chords," said Mr. Betti [and he rapidly set it down in pencil].

[Illustration: Musical Notation]

"Now let us begin by fixing the B so that it is perfectly in tune with
the E, then _without at all changing_ the B, take the interval D-B. You
will see that the sixth will not be in tune. Repeat the experiment,
inverting the notes: the result will still be the same. Try it yourself
some time," added Mr. Betti with a smile, "and you will see. What is the
reason? It is because the middle B has not been adjusted, tempered! Give
the same notes to the first and second violins and the viola and you
will have the same result. Then, when the 'cello is added, the problem
is still more complicated, owing to the difference in _timbre_ and
register. Yet it is a problem which can be solved, and is solved in
practically everything we play.

"Another difficulty, especially in the case of some of the _very daring_
chords encountered in modern compositions, is the matter of balance
between the individual notes. There are chords which only _sound well_