During the whole period of church counterpoint, which never lost the radical elements of its character until after Legrenzi's day, music felt the influence of the old chant and the early study of the canonic style. In concluding the account of this period, I cannot do better than to quote a few luminous sentences from the admirable "Evolution of the Art of Music" by Dr. C. H. H. Parry: "Of definite principles of design beyond this elementary device [the canon] these composers had but few. Their treatment of musical figures and melodic material is singularly vague. The familiar modern practice of using a definite subject [part of a distinct tune] throughout a considerable portion of a movement, or at certain definite points which have a structural importance, was hardly employed at all. The voices, which entered one after another, naturally commenced singing the same words to phrases of melody which resembled each other. But composers' ideas of identity of subject matter were singularly elastic, and even if the first half-dozen notes presented similar contours in each voice part successively, the melodic forms soon melted into something else, and from that point the movement wandered on its devious way without further reference to its initial phrases." This points to one of the fundamental differences between the music of the polyphonic era and that of the monophonic, in which one voice or instrumental part (as the treble of a piano) uttered a melody full of periodical repetitions of the germinal tune-thought, and the other parts supplied an accompaniment of chords. This style of composition was developed first in the opera and afterward by instruments. It will be more convenient to take up the progress of instrumental music first, and at the outset let us review the evolution of the piano. Chapter VII The Evolution of the Piano Plucking and striking strings--The dulcimer--Invention of the keyboard--The clavichord and its action--Manner of playing the clavichord--The harpsichord family--Invention of hammer action--Claims of Cristofori--Modern improvements--Equal temperament.