[11] As to the characteristic sounds of the different keys, the views of musicians are to the present day divided. Many even of our most eminent theorists, as Hauptmann, for example, in Leipsig, have maintained that all keys (_Tonarten_) are only transpositions of one major and minor key, and that like musical effects may be produced with one as well as with the other. The majority of musicians are, however, of the opinion that each key has its peculiar character, and that by transposition into another key the musical effect is changed. My son, Carl Seiler, has discovered that each key has its own peculiar, prominent over-tones, which determine its distinctive character. A table of all the keys (_Tonarten_), in which the prominent over-tones of each are given, shows also that the mutual relation of the keys (_Tonarten_) is elucidated by these over-tones. And thus again scientific investigation confirms what the founders of the theory of music, with their sound sense for the beautiful, recognized as correct. [12] The position of the body in singing must be such as in no way to interfere with the easy drawing of the breath. One sings most easily standing as erect as possible, quiet and unconstrained, the chest somewhat projected, the body slightly drawn in, and the hands folded. [13] It was instruments of this class--trumpets, horns, bugles, etc.--in whose timbre the highest inharmonic over-tones overpower all the rest, that were painfully offensive to the exquisite musical organization of Mozart from his earliest childhood. [14] It is all but impossible to give an idea of what is meant by _Tonansatz_, without a practical illustration. It is that striking of the note or the air corresponding to the touch in piano-playing. [15] A selection of such exercises, prepared by the present writer, has recently been published by Mr. O. Ditson in Boston, and also two books of old Italian solfeggi from Mieksch and Mazzoni, arranged to the present pitch. [16] According to _Boethius_, the _lyra_, which was used by the Greeks to accompany declamation, embraced, in the tuning of its strings, the principal intervals used in speaking.