The name symphony, from sinfonia, a consonance of sounds, applied originally to any selection played by a full band and later to instrumental overtures, was given by Joseph Haydn to the orchestral sonata form inaugurated by him. His thirty years of musical service to the house of Esterhazy, with an orchestra increasing from 16 to 24 pieces to experiment on, as the solo virtuoso experiments on piano or violin, brought him wholly under the spell of the instruments. Their individual characteristics afforded him continually new suggestions in regard to tone-coloring, and he rose often to audacity, for his time, in his harmonic devices. Grace and spirit, originality of invention, joyous abandon, a fancy controlled by a studious mind, a profusion of quaint humor and a proper division of light and shade, combine to give the dominant note to his music. His symphonies recall the fairy tale, with its sparkling "once upon a time," and yet like it are not without their mysterious shadows. In everything he has written is felt that faculty of smiling amid grief and disappointment and pain that made Haydn, the Father of the Symphony, exclaim in his old age, "Life is a charming affair." With Mozart, whose life-work began after, but ended before that of Haydn, influencing and being influenced by the latter, the symphony broadened in scope and grew richer in warmth of melodious expression, definiteness of plan and completeness of form. His profoundly poetic musical nature, with its high capacity for joy and sorrow and infinite longing, was reflected in all that he wrote. By means of a generous employment of free counterpoint, in other words a kind of polyphony in which the various voices use different melodies in harmonious combination, he gained a potent auxiliary in his cunning workmanship, and emphasized the folly of rejecting the contrapuntal experiences, of, for instance, a Sebastian Bach. Musical instruments, as well as musical materials, were his servants in developing the glowing fancies of his marvelously constructive brain. The crowning glory of his graceful perfection of outline and detail is the noble spirit of serenity which illumines all its beauty.