to_, gradually increasing the speed, to the
Italian word _scala_, singing the syllable _la_ to the last note.

The change from one register to another should always be made a couple
of tones below the extreme limit, so that there will be at the juncture
of every two registers a few "optional" tones which it is possible to
take with both mechanisms. The singer will be wise, however, to avail
himself of the power of producing an optional tone with the mechanism of
the lower register only on rare occasions. To force the register beyond
its natural limit is, of course, infinitely worse, and should never be
tolerated. The practice carries its own punishment, as it invariably
ruins the voice; and tones so produced always betray the effort
(frequently in a most painful degree), and are consequently never
beautiful.

It is to be observed that the exercise given above may be varied to any
extent, so long as it is based upon the principle which has been
explained. The beneficial results in the development of the voice will
speedily be noticed, and then sustained tones may be sung through the
whole compass after the orthodox fashion.

This brings me to the consideration of the "mixed voice," which is
essential in bridging over the break between the "upper thick" and the
"lower thin" of the tenor, and which is also frequently made use of by
baritones and basses in the production of their highest tones.

The "voce mista" is "mixed" in this sense, that it combines the
_vibrating mechanism_ of the "lower thin" with the _position of the
larynx_ of the "lower thick;" that is to say, while the vibrations are
confined to the thin inner edges of the vocal ligaments, the larynx
itself takes a lower position in the throat than for the "lower thin,"
and the result is a remarkable increase of volume without any
corresponding additional effort in the production of tone. A few trials
before a looking-glass will at once prove the correctness of this
explanation, and, what is of more practical consequence, will enable the
student with a little practice to overcome the serious difficulty of
singing high tones without straining, yet with a fulness capable of
being increased or diminished at pleasure.

The last thing we have to consider is the "resonator" of the human
voice, namely, the upper part of the throat, the mouth, and the nose.
Whether we sing _ah_, _ai_, _ee_, _o_, or _oo_, the original tone
produced by the vibrations of the vocal liga