Of the various qualities (as they are called) of impure voice, the =Aspirate=, the =Sibilant=, and the =Guttural= are defined with sufficient clearness, by their names. Though these modes can be appropriately used only occasionally, nevertheless they are of great value to the reader, and the voice should be trained to assume them whenever necessary. Great care must be exercised, however, that impurities shall never be present as characteristics of _normal_ utterance; this, whether from the head or chest, should be distinct, sonorous, and smooth, and should exhaust every particle of air expired. Another impure quality is the =Pectoral=, which is an aspiration produced, as it were, from the lowest cavities of the chest; and still another is the =Falsetto=, an unnatural voice, that seems to be produced entirely in the upper cavities of the head. The employment of the Falsetto at any time, either in speaking or reading, is of doubtful taste. EXERCISE.--1. With the syllable _haeh_ exemplify severally the aspirate, guttural, and pectoral qualities, first with insufficient vocality, then with sufficient. Exemplify the sibilant impurity with such syllables as _pish_, _false_, _traitress_, _miscreant_. In those exercises employ intervals of varying lengths, different degrees of initial pitch, and the several varieties of stress; and let the utterances be made effusively, expulsively, and explosively. 2. Select appropriate passages in "The Raven" (p. 258) for exercise in natural, orotund, aspirate, guttural, and pectoral qualities. Read the passages severally with appropriate intonations,--it may be somewhat exaggeratingly. Then read the whole poem feelingly, with appropriate, but not exaggerated intonations. So far, what has been said has had reference mainly to the cultivation and improvement of the voice, by the analogies and description of the various effective modes in which it can be manifested, and by the suggestion of suitable exercises for increasing its endurance, strength, flexibility, and resonance. It remains now to discuss shortly some of the principles of _vocal interpretation_,--that is, to discuss what modes of voice-action are appropriate to the representation of the various emotions which the wide range of literature presents to the reader.