In regard to the much discussed tempo rubato of Chopin many and fatal blunders have been made. Players without number have gone stumbling over the piano keys with a tottering, spasmodic gait, serenely fancying they are heeding the master's design. Reckless, out-of-time playing disfigures what is meant to express the fluctuation of thought, the soul's agitation, the rolling of the waves of time and eternity. The rubato, from rubare, to rob, represents a pliable movement that is certainly as old as the Greek drama in declamation, and was employed in intoning the Gregorian chant. The recitative of the sixteenth century gave it prominence, and it passed into instrumental music. Indications of it in Bach are too often neglected. Beethoven used it effectively. Chopin appropriated it as one of his most potent auxiliaries. In playing he emphasized the saying of Mozart: "Let your left hand be the orchestra conductor," while his right hand balanced and swayed the melody and its arabesques according to the natural pulsation of the emotions. "You see that tree," exclaimed Liszt; "its leaves tremble with every breath of the wind, but the tree remains unshaken--that is the rubato." There are storms to which even the tree yields. To realize them, to divine the laws which regulate the undulating, tempest-tossed rubato, requires highly matured artistic taste and absolute musical control. Too sensitive to enjoy playing before miscellaneous audiences whose unsympathetic curiosity, he declared, paralyzed him, Chopin was at his best when interpreting music in private, for a choice circle of friends or pupils, or when absorbed in composition. It is not too much to say for him that he ushered in a new era for his chosen instrument, spiritualizing its timbre, liberating it from traditional orchestral and choral effects, and elevating it to an independent power in the world of music. Besides enriching the technique of the piano, he augmented the materials of musical expression, contributing fresh charms to those prime factors of music melody, harmony and rhythm. New chord extensions, passages of double notes, arabesques and harmonic combinations were devised by him and he so systematized the use of the pedals that the most varied nuances could be produced by them. In melody and general conception his tone-poems sprang spontaneously from his glowing fancy, but they were subjected to the most severe tests before they were permitted to go out into the world. Every ingenious device that gave character to his exquisite cantilena, and softened his most startling chord progressions, was evolved by the vivid imagination of this master from hitherto hidden qualities of the pianoforte. Without him neither it nor modern music could have been what it is. An accentuation like the ringing of distant bells is frequently heard in his music. To him bell tones were ever ringing, reminding him of home, summoning him to the heights.