The standard instrument of the Greeks was the octave lyre. The lowest and highest strings were tuned respectively A, fifth line bass staff, and A, second space, treble.
[Dorian Octave. Signature B♭] [Phrygian Octave. Signature F♯]
[Lydian Octave. Signature F♯, C♯ & G♯.] [Mizo-Lydian Octave. Signature B♭ & E♭.]
[Hypo-Dorian Octave.] [Hypo-Phrygian Octave. Signature F♯ & C♯.]
[Hypo-Lydian Octave. Signature F♯, C♯, G♯ & D♯.]
These were fixed sounds, but the tuning of the remaining six strings might be changed at will; therefore, a series of sounds belonging to any one of these scales could be made; and it will be seen, on examining the following table, that all the seven scales may be represented without changing the extreme notes, A to A. Suppose we make the B flat. Now B-flat is the characteristic note of the Dorian Scale, in our term, its signature. Therefore this octave would be called the Dorian Octave, not Dorian Scale. We speak of a scale as beginning and ending on its keynote; if it does not, we call it a scale passage in such and such a key.