to this register,
their voices lose the baritone timbre, take on a feminine quality, and
become male altos.

In other words, there are three registers, and they correspond for all
voices, but certain voices sing more in one register than in the others.
Thus, the lowest register is the special province of the alto and the
bass; soprano and tenor can come down only a few notes into it. The
middle and the highest registers are the special province of soprano
and tenor. The ordinary alto and bass can come up only part way into
the middle register and cannot follow soprano and tenor at all into
the highest.

The division of the registers which I have made is subject to many
practical exceptions, which so far I have avoided mentioning, because I
wanted to fix in the reader's mind the fact that the registers are the
same for all voices and are determined by the special adjustment of the
vocal apparatus required for their production, and not by voice-quality.
Now and then in a generation there may appear upon the scene a singer,
usually tenor, who for his high notes is not obliged to adopt the
somewhat artificial adjustment required by the highest register, but can
sing all his tones in the easier adjustments of the lowest or middle
register. But he is a phenomenon, the exception that proves the rule.
Another practical exception to my rigid division of the registers is
furnished by the overlapping of registers, the capacity of a singer
to produce the lower notes of one register with the vocal adjustment
employed for the higher notes of the register below, and vice versa;
so that where the registers meet there are possibly some half a dozen
optional notes. Most basses and baritones, for example, sing only in
one register, that is, they carry the vocal adjustment for the lowest
register into the notes they are able to sing in the register above.
These exceptions will be considered later. At present, in order to
treat this difficult subject in something that at least approaches an
elementary manner, it is necessary to make the division of the vocal
scale into registers a somewhat rigid one.

It is, then, the three different adjustments of the vocal tract which
determine the three divisions of the vocal scale and likewise the
positions or registers for each division. The basis, therefore, for the
division of voice-production into registers is not haphazard, but rests
on the science of physiology. That there are not separate regi