80 On Perfect Musical Intonation. 
It is supposed that each of these four chords contains ” 
same identical sownds: and on the oe it is Impossi 
to obtain any other than the same sounds, in the four different 
keys. These four chords have therefore ein ‘shneel to be 
one and the same thing. Mention is, mdeed, made of the 
“ enharmonic change’ of G# to Ab, F to EF, D to C+, &e.; 
but as on the piano forte it is impossible to make any change— 
that instrument having but one sound to answer for the two or 
more, which appear in the written music—the idea has preva ailed 
that the change is merely imaginary, and that the alteration 
in the mode of writing the note, is made only to prevent one 
key from being mistaken for another, in the appearance of the 
written music to the eye. But the truth is, that in perfect in- 
tonation, an enharmonic change oper means the alteration 
of a note by a small interval. And not only are enharmonie 
changes made when the written music phen a sharp changed 
to a flat, and vice versd, but changing the signature will often | 
_ produce an enharmonic a This point will be more fully 
illustrated when we have spoken of transposition and modulation, 
and explained our system of notation. 
As musical composition would be very limited in variety, 
if confined to a single scale or key, other scales have been con- 
structed on new key-notes, separated one from the other by inter- 
vals of perfect fifths, and from these key-notes, the remaining 
notes of each scale are placed at the same intervals which were 
adopted in the construction of the original. If we take the fifth 
of any scale as the key-note of a new scale, and complete it with 
the same intervals as the first, we shall find that two sounds will 
be introduced which were not found in the original scale. We 
take for example the diatonic scale of C, and ne its fifth 
G as key-note, complete the scale of G. The second of this 
scale will be A, and from G to A, or the first to the nk must 
be a major tone, (15.) On engine. the scale of C, (14) we find 
that the A of that scale is but a minor tone, from G. We must 
therefore introduce a new A, a comma higher than the first, and 
a major tone from G. Every other note of the C scale is correct 
for the G scale with the exception of F, which must be raised a 
chromatic semitone to F'#, to form the seventh of the scale of G. 
In general, the scale may be transposed to any extent by the fol- 
lowing rules. 
writer has been led into this digression on the subject of the “diminished 
seventy from pa that it has been trea’ ted, as he considers erroneously, in all the 
scien orks that have fallen under his observation, and it has been ae 
an o ston 108 a hiherser of perfect intonation. Since the article was in t, 
‘stay informs him, that po. views as Weber an oth- 
hed seventh, have been rejected by V Vogler and the 
bet Geral theoea ‘ 
