_Frederick Wiek_ has composed for his pupils a large number of simple exercises, in which all kinds of ornaments are introduced, and which at the same time are so melodious that they easily catch the ear. They mostly comprise only a few tones, at the most an octave, and are sung in half tones, ascending in different keys. Next to these exercises come, as highly adapted to the culture of vocal flexibility, the solfeggi of _Mieksch_, _Mazzoni_, _Rossini_, _Crescentini_, &c. There is, indeed, no want of excellent exercises and solfeggi. Their use, however, depends upon the way in which the teacher requires them to be practised. Notwithstanding the abundance of these exercises, I have always found it necessary to prepare special ones for my pupils, as every voice requires peculiar treatment and guidance.[15] In every pupil peculiar faults are to be overcome and peculiar qualities come into play, and the vocal organ shows as many differences as the human face. But the right way is sure to be found when the irreversible laws of nature, which lie at the foundation of our art, are once recognized. The practical advantages of this knowledge the singer, like every other artist, must endeavor to secure orally, that is, by sound instruction. Ornamentation, however, can become distinct and clear only by uniting these with a distinct, pure touch, as we have already endeavored to describe, when, with the beginning of the tone, the pitch is struck lightly, quickly, distinctly, elastically, with certainty and perfect correctness. But as it is by no means easy to introduce a tone quickly and correctly, so that it will sound equally pure from the first, this flexibility is extremely rare among our singers. Instead of it, the most hateful mannerisms have stolen into practice; the tone is struck too low, and forced up by an increase of breath, or the tones are so drawled one into another that one cannot tell where they begin or where they cease. Impure intonation is much more disagreeable in the high tones than in the low. This is quite natural; for when, for example, the low _c_ is sung one-tenth too low or too high, then it will cause an octave higher twice as many vibrations, and two octaves higher four times as many, and these in proportion to their number produce a more intense effect. In the higher registers of the tones little discords (_Verstimmungen_) call forth a much larger number of beats (which are not to be confounded with vibrations) than in the lower, and thus the impurity of the musical intervals is felt much more strongly. Purity in the art of singing is, however, such a primal condition of its beauty, that a piece of music purely executed, even by a weak and slightly-cultivated voice, always sounds agreeably, while the most sonorous and practised voice offends the hearer when it is out of tune or forced upwards. The training of our singers by pianos, as they are now tuned, by equal temperament, is altogether unsatisfactory.