Mozart's autograph Thematic Catalogue contains few important works between his return to Vienna and his second journey to Prague:-- 1787. March 11. Rondo for pianoforte, A minor (511 K.). March 18. Scena for Fischer, "Non sö d'onde viene" (512 K.). March 23. Air for Gottfried von Jacquin, "M entre ti lascio" (513 K.). April 6. Rondo for the horn, for Leutgeb (514 K.). April 19. Quintet for two violins, two violas, and violoncello, C major (Vol. III., p. 19) (515 K.). May 16. Quintet, G minor (Vol. III., p. 20) (516 K.). May 18, 20, 23, 26. A song on each (517-520 K.). May 20. A piano sonata for four hands, in C major (521 K.). June 11. A musical jest (Vol. II., p. 367, 522 K.). June 24. Two songs (523, 524 K.). August 10. Serenade (525 K.). August 24. Pianoforte sonata with violin, in A major (526 K.). These were probably all composed for social or teaching purposes; even the two quintets, which are worthy of the first rank, were no doubt written to order for a particular musical circle. Nor were these compositions to the taste of the Viennese public of the day. The traveller already mentioned notes as follows:[9]-- Kozeluch's works hold their ground, and are always acceptable, while Mozart's are not by any means so popular. It is true; and the fact receives fresh confirmation from his quartets dedicated to Haydn, that he has a decided leaning to what is difficult and unusual. But on the other hand, how great and noble are his ideas--how daring a spirit does he display in them! The amount of industry with which Mozart worked at "Don Giovanni" is unknown to us. We may conclude that, if he followed his usual habit, he plunged eagerly into his new libretto at first, and afterwards procrastinated over {DON GIOVANNI.} (130) the actual transcription of his ideas. The received tradition represents him as bringing the unfinished opera to Prague in September, 1787,[10] and completing it, incited by intercourse with the intended performers and the stimulating society of his enthusiastic friends and admirers.[11] The impresario, who was bound to provide accommodation for the composer until after the performance, had lodged Mozart in a house, "bei drei Löwen" (on the market-place).[12] He preferred, however, the vineyard of his friend Duschek at Kossir (Kosohirz); and the summer-house and stone table are still shown at which he used to sit writing his score, with lively talk and bowl-playing going on round him.[13] All such stories as those of the delicate diplomacy with which Mozart apportioned the several parts to the satisfaction of the performers, of his having been obliged to appease L. Bassi, indignant at Don Giovanni having no proper grand air to sing; of his having composed "La ci darem la mano" five times before he could satisfy the singers,[14] repose on the same foundation as those of his {PERFORMANCE IN PRAGUE, 1787.} (131)