This being the case, intelligible instruction in the use and management of chest resonance is hardly to be expected. Teachers of singing are obliged to fall back on purely empirical instruction on this topic. This usually takes the form of a description of the sensations experienced by the singer when producing tones in the chest voice. How this description of the singer's sensations is applied, is discussed in the following chapter. _Nasal Resonance_ The lack of connection between the theories of vocal scientists and the practical methods of singing teachers is well illustrated in the subject of nasal resonance. A striking feature of all the discussions concerning the use or avoidance of nasal resonance is the fact that vocal theorists base their opinions entirely on empirical observations. The use of nasal resonance is condemned by almost every prominent authority on Vocal Science. Yet the only reason ever advanced for condemning nasal resonance is the fact that a tone of objectionable nasal quality seems to "come through the nose." This fact cannot, of course, be questioned. It is mentioned by Tosi, who speaks of the "defect of singing through the nose," and is observed by everybody possessed of an ear keen enough to detect the nasal quality of sound. It is generally stated by vocal theorists that the nasal quality is imparted to the tone by the influence of the resonance of the air in the nasal cavities. In order to prove this assertion Browne and Behnke offer the following experiment, (quoted in substance): "Hold a hand-mirror flat, face up, just below the nostrils. Then sing a nasal tone; you will note that the mirror is clouded, showing that part of the breath has passed through the nasal cavities. Now sing another tone, free from the fault of nasal quality; this time the mirror is not clouded, which proves that no air has passed through the cavities in question." (_Voice, Song and Speech._) This experiment is simplified by other authorities, who direct that the nostrils be pinched by the fingers, and then allowed to open by the removal of the pressure of the fingers. A steady tone is meanwhile to be sung. It will be noted, according to these theorists, that with the nostrils open the tone is nasal, and with the nostrils closed the tone is not nasal. This proves to their satisfaction that a tone passing in whole or in part through the nasal cavities must be nasal in quality. It must be noted here that these experiments are not in any sense convincing. A tone of objectionable nasal quality can be sung equally well with the nostrils either closed or open, and so can a tone free from the nasal quality. In theory, the mechanical prevention of nasal resonance is very simple. It is necessary only to raise the soft palate in singing, and thus to cut off the expired breath from passing into the nasal cavities. Most vocal scientists advise that the singer hold the soft palate raised for every tone.