1. There are two very great obstacles to the perfect production and performance of a trill. The first, that no infallible rules to teach it have yet been found, embarrasses the teacher; the second, that ungenerous Nature endows him with little [ability], plagues the student. The impatience of the teacher unites with the desperation of the student, so that the former abandons the effort and the latter the application. The master is then guilty of a double mistake: first, by not doing his duty and second, by leaving the student in ignorance. One must struggle against these difficulties until they are finally surmounted.

2. Whether it is necessary for one who wants to sing to be able to produce a good trill, one should ask the masters [best practitioners] of the art–for they know better than all others what great obligation they owe to the trill, either when they have been surprised by an unforeseen distraction; or else when, on account of the sterility of the dulled imagination, they are not in a position to hide from the audience the poverty of their knowledge, manifesting itself at just the wrong time–to what extent the trill has come to their rescue.

3. He who can produce a beautiful trill, though he has no store of other ornaments, always has the advantage of acquitting himself with honor at pauses or cadences of the melody where the trill is most indispensable.