One prevailing difficulty with voices which are not perfectly educated is that the wrong quality is given for the pitch. Each interval of the scale requires a different resonant quality, and this necessitates a difference in the sizes of the resounding chambers. This difference is provided for in the graded sizes of the different portions of the nares, and in the pharynx and trachea. However, notwithstanding the freedom of the resonant chambers here mentioned, this proper quality of the voice would be interfered with in the speaking and singing _words_, or even _elements of words_, the freest of which are vowels, unless the transient chambers of resonance were perfectly formed. If words seem to interrupt and injure a singing tone, it is because the transient resonant chambers in which they are formed are not properly constructed. The only way to perfect the forms of the transient resonant chambers is by holding the elements of speech in the mind as distinct objects of thought while speaking or singing them. Such is the natural service of the vocal organs to the mental concepts, that these mental objects will, through the cranial nerves which control the organs of speech, externalize themselves by producing exact molds of resonance. It takes time and practice to develop the power of holding the elements as distinct objects of thought; it takes still more time and practice to develop the power of holding these sounds as mental objects while the mind materializes them in the voice. This power, like all powers, grows in the ratio of repetition guided by continued mental concentration.