In the former of these he sets forth a detailed account of the results which he himself obtained in connection with the human voice from the use of the instrument; in the latter he has told the story of the invention and given a full description of the laryngoscope. Last of all, there is the question of his remarkable age. As a centenarian, he passed through many great historical events, and witnessed a number of changes not only in the musical world, but in the general advance of civilisation. To mention but a few cases of the former: his childhood in Spain was passed amid the scenes of the Napoleonic invasion, followed by those of the Peninsular War, while his boyhood in Naples caused him to witness the execution of the ex-king Murat, a few months after the despotic brother-in-law's final overthrow at Waterloo. His first visit to England was made when George III. was on the throne; his nineteenth year saw the death of Louis XVIII.; while his arrival in America to take part in the first season of Italian opera ever given there was at a time when New York was a town of 150,000 inhabitants, and the United States were preparing to celebrate the jubilee of the Declaration of Independence. In early manhood he joined the French Expedition against Algiers, and on his return found himself in the midst of the July Revolution, which resulted in the expulsion of Charles X. from the capital and the placing of Louis Philippe on the throne; while he spent his last months in Paris as a member of the National Guard during another revolution, that of 1848, which ended in the flight of Louis and the proclamation of the French Republic. The first fifteen years of residence in London saw the English nation throw down the glove to Russia, enter on the Crimean War, and bring it to a successful close with the fall of Sebastopol, which was followed by such events as the Indian Mutiny; the accession of William I. to the throne of Prussia, with Prince Bismarck as his chief adviser; the capture of Pekin; the American Civil War; the death of the Prince Consort, and two years later the marriage of the heir to the throne of England to the beautiful Princess of the Royal House of Denmark. He was in his sixty-first year when Lord Palmerston died; as for the Franco-Prussian War and the Siege of Paris, they were looked on by him in his old age as things of but yesterday; while at various periods of his life he resided in Madrid, Naples, Paris, New York, Mexico, and London. Again, in his work as a teacher, there came for lessons not merely the children of old pupils, but many even whose parents and grandparents had studied under him; while before his life was brought to a close England had been ruled by five successive sovereigns.