Secondly, we must know the physical order in virtue of which these phenomena may be acquired or developed.  The various special exercises and the vices to be avoided constitute phonation or the practical study of the voice.

Thirdly, we must know and appreciate the physiological, intellectual and moral meaning of these elements, the different relations of resemblance, of opposition and of identity which exist between these different phenomena.

The modes of application or principles of style form the transcendent study or aesthesiophony, that is, the voice applied to feeling, etc.

What the Register is.

The register is an intrinsic modification of the sound; a modification which is produced in the larynx itself and which does not belong to the mouth.  Now, we may say of registers that they are to the larnyx what emissions are to the mouth.  Thus registers form a physiognomy which the sound assumes in the larynx, and emissions form the physiognomy which that same sound takes on in the mouth.

On Shading.

Light and shade are not, as has been asserted, subject to the arbitration or inspiration of the moment.  They are ruled by laws; for in art there is not a single phenomenon which is not subject to absolute mathematical laws.  A knowledge of these laws is important, the art of shading forming the basis of style.

The opinion which makes the ascending phrase progressive is false six times out of seven.  It is only correct in the following cases: 

1.  If an ascending phrase encounters no repeated and no dissonant note it is progressive, and the culminating note is the most intense.  It has one degree of intensity.

2.  If we find a note repeated in the ascending phrase, that note, even if it be the lowest of all, must be made more important than the highest note and will have two degrees of intensity.  In this case, the higher the voice rises the softer it must become; for there cannot be more than one culminating point in a musical phrase any more than in a logical or mimetic phrase.  All sounds must, therefore, diminish in proportion to their distance from this centre of expression, from this repeated note.  The reason of the intensity of a repeated note lies in the fact that we repeat only that thing which we desire, and this intensity gives it a greater value.

3.  If the repeated note be at the same time the culminating note, it will require a new degree of intensity.  It will have three degrees of intensity.

4.  We may possibly find a dissonant note in the ascending phrase, with a repeated culminating note. (This note would, then, be more than an indication; it would receive an adjective form from the accident, assuming in the musical phrase the value that an adjective would have in a logical phrase.) Its intensity, therefore, would be greater than that of the highest repeated note, and it would have four degrees of intensity.