The whole scene was eminently successful; the lady to whom it referred rewarded me by looks full of delighted amiability; and the princess Eliza, after loading me with praises, enquired if, after doing the impossible with _two_ strings, _one_ might not possibly suffice me. I instantly gave my promise to make the attempt; and, a few weeks afterwards, I produced a _Sonata on the fourth string_, which I entitled “Napoleon,” and executed it on the 25th of August, before a brilliant and numerous Court. Its success having far surpassed my expectation, I may date from that period my predilection for the lower string; and, as my audience seemed never to tire of the pieces I had composed for it, I have at length arrived at that degree of facility which appears to have so much surprised you.” To find out sufficient scope for an entire field of melody, as the produce of a single musical string, must have demanded great study, as well as unremitting manual practice. Paganini extended the capability of the string to three octaves, including the harmonic sounds, which he developed into a most important resource. The success of this novelty was prodigiously increased, after he had presented it beyond the courtly circle, and made it public[37]. When the Princess Eliza became Grand Duchess of Tuscany, Paganini followed her to Florence, where he became an object of even fanatic admiration. His talent developed itself daily in new forms; but he had as yet very imperfectly learned to regulate its exercise. The amount of study, however, to which he had subjected himself, after ceasing to be the slave of his father, is a thing to excite astonishment. He had abandoned himself, in solitude, to the research with which his mind was occupied; and had then formed the plan of the _Studies_ which are known under his name, and wherein he proposed difficulties that he himself could not surmount without immense labour. It is a remarkable fact, also, that he suddenly interrupted his enquiries as to the possibility of augmenting the resources of the violin, in order to study seriously the works of Corelli, Vivaldi, Tartini, Pugnani and Viotti, and to ascertain the successive progress of his instrument. He afterwards familiarized himself with the works of the Violinists of France. In the summer of 1808, after three years passed at Lucca, Paganini, with the consent of his patroness, visited Leghorn, which city had been a scene of triumph to him seven years previously. How, at his first concert on this re-appearance, a cloud was converted into sunshine, has been pleasantly enough recorded by himself:—