It was not long before the transition period began,--that period in which musicians and composers tested and decided upon that which was best and most fitting in the treatment of these respective instruments. Nowhere can we find more evident signs of this time of experiment, this gradually leaving old landmarks and seeking a new form of expression, than in the works of Bach himself. In the "Well-Tempered Clavier" we find preludes and fugues impossible to properly interpret on any other instrument except the piano, placed side by side with those whose real significance can only be developed upon the organ. In a portion of the pieces written especially for the organ, we find, on the other hand, passages which to modern ears are only fit for and tolerable on the piano. The dividing lines of effect, not to say possibility, had not as yet been fully marked out. The organ was no more disposed to give up its long sway, and be narrowed to its own particular sphere, than any other sovereign, when the limiting influences of modern times first began to make themselves felt. Like them, however, it was obliged to yield. Little by little the piano emancipated itself from the _strict_ contrapuntal chain which bound it to the organ, until, in the sonatas of Mozart and Beethoven, it emerged into a new life. Here it was strengthened by the _free_ contrapuntal treatment it received, like the fruits of early education showing themselves in new and original forms,--speaking a language founded indeed on the past, but new, fresh, and sparkling; or, when adopting the strict style, taking it up as a matter of choice, but not of compulsion. Such results followed the invention of the harpsichord,--the early piano,--and here we must leave it. It would, however, be an interesting subject to trace this development down to Chopin, Liszt, and the modern Titans of the piano, showing how gradually the mutual treatment of piano and organ disappeared and what was substituted in their place. It could, however, only be satisfactorily done by musical examples. Meanwhile the orchestra blossomed into a new significance. To us moderns who read its history, or look back into the scores which antedate this time, it does not seem so much a period to be described, as that of progress, as that of a veritable new birth itself, a new creation. And this is, indeed, the fact; for no improvements in ancient instruments, although they took place, nor addition of new ones, can account for the change which now occurred in the orchestra. Here it was _the man_, not the instrument; and the name of Joseph Haydn will always be quoted as "Father of the Modern Orchestra."