high Notes of an excellent Voice,[39] perfect in this
rare Quality, and not made use of too often, it cannot displease even
Envy itself.

Sec. 13. The eighth is the _Trillo-Mordente_, or the _Shake_ with a _Beat_,
which is a pleasing Grace in Singing, and is taught rather by Nature
than by Art. This is produced with more Velocity than the others, and is
no sooner born but dies. That Singer has a great Advantage, who from
time to time mixes it in Passages or Divisions (of which I shall take
Notice in the proper Chapter). He, who understands his Profession,
rarely fails of using it after the _Appoggiatura_; and he, who despises
it, is guilty of more than Ignorance.[40]

Sec. 14. Of all these _Shakes_, the two first are most necessary, and
require most the Application of the Master. I know too well that it is
customary to sing without _Shakes_; but the Example, of those who study
but superficially, ought not to be imitated.

Sec. 15. The _Shake_, to be beautiful, requires to be prepared, though, on
some Occasions, Time or Taste will not permit it. But on final Cadences,
it is always necessary, now on the Tone, now on the _Semitone_ above its
Note, according to the Nature of the Composition.

Sec. 16. The Defects of the _Shake_ are many. The long holding-out _Shake_
triumph'd formerly, and very improperly, as now the Divisions do; but
when the Art grew refined, it was left to the Trumpets, or to those
Singers that waited for the Eruption of an _E Viva_! or _Bravo_! from
the Populace. That _Shake_ which is too often heard, be it ever so fine,
cannot please. That which is beat with an uneven Motion disgusts; that
like the Quivering of a Goat makes one laugh; and that in the Throat is
the worst: That which is produced by a Tone and its third, is
disagreeable; the Slow is tiresome; and that which is out of Tune is
hideous.

Sec. 17. The Necessity of the _Shake_ obliges the Master to keep the
Scholar applied to it upon all the Vowels, and on all the Notes he
possesses; not only on Minims or long Notes, but likewise on Crotchets,
where in Process of Time he may learn the _Close Shake_, the _Beat_, and
the Forming them with Quickness in the Midst of the Volubility of Graces
and Divisions.

Sec. 18. After the free Use of the _Shake_, let the Master observe if the
Scholar has the same Facility in disusing it; for he would not be the
first that could not leave it off at Pleasure.

Sec. 19. But the teaching where the _Shake_ i