When we read of the various Greek modes—of the Dorian scale, the Phrygian, Lydian, Mixo-Lydian, Hypo-Dorian, and others—we should not forget that one was added to the other in order of time, and the full system only gradually evolved. And in this Etruscan period, the music was probably limited to the single tetrachord on three modes, and so remained for a long time. We, in some instances, see on the vases that the pipes are marked with three holes each, sometimes with four; although it is rarely that the holes are indicated at all. The Egyptian flutes had three holes to one pipe and four to the other, which only extended the scale one note higher than the three holed. In these Etruscan flutes, however, it is by no means clear that the second flute extended the compass, for the holes seemed to occupy in each the same position as to distance. It is open to consideration that a difference in the pitch of the reed itself of one of the pipes, would possess the power of influencing that pipe to the extent of a semi-tone, if such entered into the design of the instrument, and so we find a reason for the second pipe. On my models, I sometimes make a difference of a whole tone in each note of the scale produced. In default of any true knowledge of Greek practice, I think that we may fairly attribute to the artist some such design in the construction of the pipes. It is a natural conclusion that the first invention of man in the way of flutes would be a single pipe for the production of one, two or three notes; then with a sense of a scale the four notes. From the single pipe the double pipe would arise, with a view to some _variation_ of such a scale, to which the ear was predisposed, and so the method of double pipes would be fixed by custom. We may be quite sure that when double pipes were first adopted there was a meaning in the method. The assumption that one pipe preceded the two does not seem to hold in the case of these bulbed flutes with the four holes, they seem to start as _di-aulos_. The Etrurian vases give no instance of single flutes. In truth, another invention was necessary, and it came in course of aftertime from the Greek mind. Like most useful inventions, it was marvellously simple—nothing other than the giving of _six holes to one pipe_, and fingering the one pipe with fingers of both hands, and with one thumb added; even that thumb hole may rank as a distinct invention of intrinsic importance to art. A similar delay we know occurred in association with key-board instruments, and it was only in Bach’s usage that the thumb was raised to the rank of efficiency and placed on an equality with the fingers.