on the King, since he soon after offered him the post of Kapellmeister, with a salary of 3,000 dollars. This offer, however, consideration for the Emperor Joseph induced Mozart to decline.[25] {A PROFESSIONAL TOUR.} (232) During his stay in Potsdam, Mozart resided in the house of the well-known hom-player Thùrschmidt, with whom he had become acquainted in Paris; he was a constant guest also of the hospitable and music-loving Sartory, an artist of architectural ornament, who had been much in Italy, and welcomed all who took interest in his favourite art; Mozart's playing and sociability made him, as may be imagined, the centre of this cheerful society.[26] Another of his friends was the charming singer Sophie Niclas, sister to the Kammer-musikus Semler, who had made a very successful appearance as Constanze in the "Entführung" in 1784:[27]-- On one occasion, at her house, he was asked to improvise something. Readily, as his custom was, he complied, and seated himself at the piano, having first been provided with two themes by the musicians who were present. Madame Niclas stood near his chair to watch him playing. Mozart, who loved a joke with her, looked up and said, "Come! haven't you a theme on your mind for me too?" She sang him one, and he began the most charming fantasia, now on the one subject, now on the other, ending by bringing them all three together, to the intense delight and amazement of all who were present.[28] Arrangements were made during Mozart's stay in Berlin for a return visit to Leipzig, where in the meantime a concert for his benefit was being organised; he arrived there on May 8. At the rehearsal for this concert he took the tempo of the first allegro of his symphony so fast that the orchestra was very soon in inextricable confusion. Mozart stopped, told the players what was wrong, and began again as fast as before, doing all he could to keep the orchestra together, and stamping the time with his foot so energetically that his steel shoe-buckle snapped in two.[29] He laughed at this, and as they still dragged, he began a third time; the musicians, {CONCERT IN LEIPZIG, 1789.} (233) grown impatient, worked in desperation, and at last it went right. "It was not caprice," he said afterwards to some musical friends, whom he had lectured only a short time before on the subject of too rapid tempo, "but I saw at once that most of the players were men advanced in years; there would have been no end to the dragging if I had not worked them up into a rage, so that they did their best out of pure spite." The rest of the symphony he took in moderate time, and after the song had been rehearsed he praised the accompaniment of the orchestra, and said that it would be unnecessary to rehearse his concerto: "The parts are correctly written out, you play accurately, and so do I"; and the result showed that his confidence was not misplaced.[30]