EXTEMPORIZATION, in music, is the art of invent ing the music performed and performing it simultaneously, in the same way as an orator speaks ex tempore when he has no notes to aid him and frames his remarks spontaneously as he proceeds. The humblest amateur who strings a few chords together is in the strict sense extemporizing, no less than the trained musician whose "profuse strains of unpremeditated art" take shape in complete and perfectly worked-out compositions. Truly marvellous were the performances in this way of some of the great masters of the past.
Thus of Bach we are told that his powers in this respect were absolutely unlimited—the inexhaustible flow of his invention being at the same time invariably combined with the most rigorous regard for form. Schweitzer tells us further concern ing him that if he improvised for as long as two hours together on the organ the theme remained the same from beginning to end.
Handel's wonderful powers in this respect drew attention to him at a very early period of his career. And these powers he retained to the end of his days, so that in the case of his organ concertos it was his habit more often than not merely to sketch in the solo part, leaving it with serene confidence to the inspiration of the moment to supply all else that was required.
As for Mozart he excited amazement even as a child by his astonishing achievements under this head. Those were the days of the musical duello, in the shape of formal contests of skill between acknowledged masters, and many were the combats of this kind in which Mozart engaged.
And not less memorable were some of the contests of the same order in which Beethoven took part. In one which caused great stir his opponent was Steibelt, an arrogant virtuoso of the day, who professed nothing but contempt for his youthful and un couth-looking opponent, but whose mortification was such as he listened to Beethoven's marvellous and inspired playing that he could finally stand it no longer and rushed out of the room. As to Beethoven's improvisation in general, many eloquent accounts have been left by those who heard him. "His extem porization," said Czerny, "was most brilliant and striking. In whatever company he happened to be he knew how to produce such an effect upon his hearers that frequently not an eye re mained dry while many would break out into loud sobs." Ries, in turn, recorded, "No artist that I ever heard came anywhere near the height which Beethoven attained in this branch of per f ormance. The wealth of ideas which forced themselves on him, the caprices to which he surrendered, the variety of treatment, the difficulties, were inexhaustible." Among more recent composers no one excelled more in this line, perhaps, than Mendelssohn, of whose extraordinary facility many astonishing stories are told—as, for instance, that of the famous three cadenzas which he introduced when playing Bee thoven's G major piano concerto with the London Philharmonic Society—the first two at rehearsal and the third, totally different from either of its predecessors, at the concert itself. Yet, his great facility notwithstanding, Mendelssohn extemporized in public with reluctance and in one of his letters even went the length of registering the determination never to perform in that way again. Did he feel, perhaps, acutely sensitive as he was, that the public listened to such performances more as feats of wonder than for the music which they heard, and so came to resent this showman-like exhibition of his powers? Four-handed improvisation, that is, by two players together, was also sometimes practised in earlier days—as by Clementi and Mozart, by Beethoven and Wolfl and by Mendelssohn and Moscheles. Needless to say this called for the highest skill.
Extemporization of another kind was that required in supply ing the embellishments and other details of a composition which were formerly left to the taste of the performer. Of such details the cadenza, or special passage for the display of the soloist's powers, in instrumental concertos is nowadays the sole surviving example, and even this in only a nominal sense. For in modern concertos the cadenzas are almost invariably provided by the composer, or if still entrusted to the soloist are assuredly never left in these days to the hazard of improvisation but are care fully prepared and rehearsed beforehand. (H. A. Sc.)