It is pretty certain that the pipe chanter was at first used without a bag, and blown directly from the mouth, as a practising chanter still is, and that its key was D, thus giving an equal number of notes above and below. Afterwards two drones were fitted into the bag along with the chanter, probably in unison with one another, and with the lower A on the chanter, the key of the Greek scale already referred to. The instrument remained in this form for a long period. In the seventeenth century probably a third and longer drone (_dos mor_) was added, tuned an octave below the others. The drones form a fixed bass, and, according to the well-established principle in music that the bass always ends with the keynote, this may furnish very good ground for saying that the true scale is A, with which, indeed, a very large proportion of pipe music ends. But taking the note D on the chanter as the keynote, it is found that the notes _above_ it are nearly in perfect tune, as can be easily observed by playing any well-known air in that key that falls within the compass of the _piob mhor_. Of course, it can be seen at a glance from the table of vibrations annexed that the scale of D is very nearly the same as that of A with a flat seventh. The use of this flat seventh descending is so common in minor scales as to form, after the minor third, one of their chief characteristics; and it does not greatly offend even the critical cultivated modern ear, when not an accented note nor leading directly to the key note. According to the principle mentioned already, that the bass always ends with the key note, it must be assumed that A is really the key note of the bagpipe scale, seeing the drones are tuned to that note; and starting from that point we find that A, C, E, A^| are Do, Mi, So, Do^| of the scale of A. Taking the higher Do of this scale and descending a fifth, we find D (Fa), and taking this as the key of a new scale, we find that D, F, A^|, A are Do, Mi, So, Soˌ of the scale of D. In the same way, taking the fifth below D—that is, G—we find that G, B, D, G^| are Do, Mi, So, Do^| of the scale of G. On referring to the table of vibrations it will be seen that all these notes are very nearly correct in the scales mentioned, whatever their Sol-Fa names, the only differences being that B should be a little sharper in the key of A than in D and G, and that E should be a little flatter in the key of G than in D and A. For comparison there is a column inserted in the table giving the vibrations according to “equal temperament” of the chromatic scale from G to A^| . None of the notes of the bagpipe admit of being sharpened or flattened except the upper G, which can be slightly sharpened by opening the E hole along with G and E. The notes D, C, B can be slightly flattened by lifting one finger only, with all those below it closed, but passages requiring this fingering are hardly met with except in pibrochs (_Ceòl mor_). The scale