But the culture of the _technique_ in the art of singing requires a special faculty in the teacher, and, together with the finest power of observation, an ear, which not only perceives the purity of the tone, whether high or low, but feels also the direction of the aerial column, the too much or too little of the breath, the coloring of the timbre, &c. An æsthetically artistic education demands likewise that the singer should have the highest general culture. As soon as the technical education has advanced so far that it no longer makes any demand upon the attention of the learner, the infusion of life and soul into the singing must be begun. The teacher must then be so filled with the spirit of his art that he shall be able so to inspire his pupils that, forgetting themselves, they may be absorbed in the high ideal work of their art, and regard their well-trained voices simply as expressing the noblest and most varied sentiments (_Stimmungen_). And on this account a teacher should seek to act upon the souls of his pupils, and awaken in them above all things a feeling for the high and the noble, that they may be able to find the correct mode of expressing it in singing. It is a very hard but not impossible work to educate true artists, who, penetrated with faith in the high worth of their art, shall fulfil its aim by exercising a refreshing and elevating influence upon their fellow-men. But, in order to be able to form true artists, a teacher must be devoted without intermission to his own culture, scientific and general; must strive with pleasure, and love, and inspiration to accomplish the high work of his calling, and make the severest demands upon himself, before he can expect anything great of his pupils. Having spoken of those parts of the _technique_ of the art of singing which rest upon impregnable natural laws, such as the registers of the voice, the formation of tones in regard to strength, pitch, and timbre, &c., let us consider more closely those other parts of the _technique_ which rest upon psychological, i.e., æsthetic principles (_Motiven_). To these belong _Rhythm_, _Correct understanding of the Tempo_, _Composition_, _Execution, that is, the delivery of the sentiment of the composition, and the aids thereto_. RHYTHM To the principles of beauty belong, above all things, order and regularity. In music this order consists in measures of time. All measurement by time, even the scientific, depends upon rhythmic, regularly returning results, as in the revolutions of the earth, of the moon, and in the vibrations of the pendulum, &c. Thus, by the regular interchange of accented and unaccented sounds in music and poetry, we obtain the rhythm of the work.