In short, the traditional precepts describe accurately the most striking points of difference between perfect singing and bad singing, so far as the effect on the listener is concerned. Modern teachers are thoroughly familiar with the highest standards of the vocal art; they fully appreciate how well the precepts describe the perfection of singing. Through long continued listening to voices, the precepts come to have a very real meaning. It is inevitable therefore that the teacher should try to impart to the pupil this intimate feeling for the voice. True, this acquaintance with the voice is purely empirical; as has just been remarked, no mechanical analysis of this empirical knowledge has ever been successfully made. The modern teacher's apprehension of the meaning of the precepts is only very vaguely connected with a supposed insight into the mechanical processes of tone-production. Yet there is nothing vague about the impression made on the teacher in listening to his pupils. On the contrary, every faulty tone impresses the teacher very keenly and definitely as being too far back, or as caught in the throat, or as falling back for lack of support, etc. How could it be expected then, that the teacher should refrain from telling the pupil to correct the faulty production, in the manner so clearly and directly indicated by the tones? But this direct application of the precepts is of absolutely no value in instruction, because of the teacher's ignorance of the mechanical processes supposedly involved. There is after all some justification for Guetta's criticism of empirical instruction. It is all very well for the teacher to feel that the pupil's voice is gripped in the throat, and to bid him "open your throat." The pupil may strive ever so earnestly to open his throat, but he does not know how, and the teacher is utterly unable to tell him. All instruction based on the empirical precepts is thus seen to be extremely unsatisfactory. While the precepts convey a very valuable meaning to the teacher, no way has ever been found for translating this meaning into rules for the mechanical management of the vocal organs. Recourse is had, to some extent, to a description of the singer's sensations; exercises on special vowels and consonants are also much used, for imparting the ideas embodied in the precepts. Both of these topics are now to be considered. _The Singer's Sensations_ The correct use of the voice awakens in the singer a variety of sensations generally held to be different from those accompanying any incorrect vocal action. One important fact must first be noted regarding the manner in which the singer's sensations are described by various authorities. The use of the voice awakens a wide variety of local sensations, which bear no necessary relation to each other. A singer may, at will, pay entire attention to any one, or to any particular set, of these sensations, and for the time being completely ignore all the others.