was a new insight into the nature of chords and the philosophy of arranging them in sequence. The outlines of these ideas had long been visible, steadily developing in Italian opera and in German writing of various kinds, but they hardly became regnant until the Austrian melodists made them conspicuous. Hence the profound difference of manner between most music before 1750 and that afterward. The older composers had worked with the instinct of true counterpoint or of a half-contrapuntal harmony. Now we encounter rather the instinct of the pure solo song or of a song-like harmony. In short, as the controlling factor in musical conception, monophony now fully replaces mediæval polyphony. That this principle, first perceived in part fully two centuries before, now took possession of the whole range of composition, is a most significant fact.
Closely associated with this was the general acceptance of the modern notion of tonality, with its classification of chords by their relation to a definite major or minor key, and its system of relative keys radiating in several directions, into which modulation can occur by definite processes. The vague and shifting tonality of the earlier periods was at last given up—with some loss of peculiar effects, but with an evident gain in unity and consistency.
We now notice a great advance in the valuation of certain instrumental methods as compared with vocal. The chamber quartet (or other small group) and the orchestra now for the first time attain their modern eminence. There was a consequent emphasis upon every device in the nature of the materials or in their detailed handling that should make the total result clear, interesting and telling for its own sake, apart from all ideas that may be conveyed by words. Thus the interests of 'absolute music' received an attention wholly new, at least in degree and significance. Following close upon this exaltation of the ensemble of solo instruments, came the rapid rise of the piano as a concerted instrument of unsuspected possibilities. Although some of these steps had been previously foreshadowed, nothing earlier had more than a fraction of the importance of what was now done.
But the vocal field was not neglected. Here there were two events of capital significance—the reclamation of the opera to dramatic sanity by Gluck, with the infusion into it of a more
