We have known a learner to derive great benefit from having it pointed out to him that certain of his vowel sounds would at once cease to be incorrect if their pitch were altered. Of course, in doing this, there were at once many changes made in the resonance-chambers, in order to get the changed pitch. Pitch, accent, and duration of the sound throw much light on the subject of dialect, as a little analysis of Irish or Scotch will show. Consonants are, as we have already said, noisy nuisances for the singer, but indispensable for word-formation, and so for human intercourse. Each has also its own pitch, and investigators have come to a measurable degree of agreement on this subject. To illustrate: Madame Seiler found that _r_ and _s_ are separated from each other by an interval of many octaves: [Illustration: C], _r_; [Illustration: b-flat'''], _s_. The latter, _s_, cannot be sounded without more or less of a hissing sound, suggesting escape of air, which is very unpleasant to the ear, and, unfortunately, these hissing sounds are very common in English, so that the speaker or singer is called upon to use all his art to overcome this disagreeable effect. This is also prominent in _whispering_--_i.e._, the escape of breath, with its corresponding effect on the ear. Whispering is effected chiefly, if not solely, by the resonance-chambers, the vocal bands taking only the slightest part, if any at all. The physiologist Bruecke, treating of the utterance of consonants, considered that they were formed by the more or less complete closure of certain doors in the course of the outgoing blast of air, and we have already referred to a consonant as an unpleasant interrupter, musically considered. Perhaps we should be disposed to compare them to the people that talk during the performance at a concert, did we not wish to avoid bringing such useful members of the speech community into undeserved disrepute. Consonants, like vowels, have their own mouth positions. This follows from their having pitch, but, in addition, they require the use of the tongue, lips, etc., in a special way. The principal articulation positions are the following: (1) Between the lips; (2) between the tongue and the hard palate; (3) between the tongue and the soft palate; (4) between the vocal bands. To indicate this, certain terms have been employed, and as they are in common use by those who treat of this subject, it will be well to explain them. _Explosives_ are consonants in uttering which there is complete closure with a sudden opening of the resonance-chambers in front, as in _b_ and _p_. [Illustration: FIG. 59 (Beaunis). Representation of the relative position of the parts and the resulting shape of the sounding chamber when the consonants indicated are formed vocally. Verification of the truthfulness of the illustrations will prove profitable.] _Vibratives_ call for an almost complete closure of the door and a vibration of its margin, as in _r_.