CDEF GABC 51 46 28 51 46 51 28 We have here three species of intervals, of which those represented by 51 are called major tones; those by 46, minor tones; and the smaller intervals represented by 28, semitones. These intervals will evidently only serve with C as keynote. If, for example, we start from D instead of C, we find E a tolerable, though not quite correct, second to V; but the third and seventh of the scale are entirely wrong. Were the major and minor tones equal, and each semitone exactly half a tone, the insertion of a note in the middle of each tone dividing the seven intervals would make it immaterial where the scale began; any one of the twelve notes becoming alike available as a keynote; and though such equality is contrary to the immutable principles of harmony, an arrangement based on it is found practically to give but little offense to the ear. In what is called the equal temperament, the twelve intervals are all of the same length, and no advantage is given to one key over the rest. This is, in theory at least, the temperament adopted in the
the pianoforte. Another system, known in this country as Smith's or the vulgar tempera ment, in which some keys were favored at the expense of others, has been much used in organs. While the keys of B%), F, C, G, D, and A are more perfect than on equally tempered instruments Ep, Ap, Dp, and Fq contain some very harsh intervals. The bad fifths and thirds which exist in these keys are designated by musicians by the name of wolf intervals. This mode of tuning the organ is being more and more abandoned for the equal temperament, or an approximation to it. The different characters of the various keys often observed on the pianoforte, as well as the organ, could have no existence were the temperament absolutely equal, and arise out of the circumstance that this strict equality is not altogether adhered to in practice.