344 HUMBOLDT Quito after a tedious and difficult journey, January 6, 1802. Their stay there was signalized by the ascent of Pichincha and Chimborazo, and terminated in an expedition to the sources of the Amazon en route for Lima. At Callao Humboldt observed the transit of Mercury on November 9, and studied the fertilizing properties of guano, the introduc tion of which into Europe was mainly due to his writings. A tempestuous sea-voyage brought them to the shores of Mexico, and after a year s residence in that province, followed by a short visit to the United States, they set sail for Europe from the mouth of the Delaware, and landed at Bordeaux, August 3, 1804. Humboldt may justly be regarded as having in this memorable expedition laid the foundation of the sciences of physical geography and meteorology in their larger bearings. By his delineation (in 1817) of "isothermal lines," he at once suggested the idea and devised the means of compar ing the climatic conditions of various countries. He first investigated the rate of decrease in mean temperature with increase of elevation above the sea-level, and afforded, by his investigations into the origin of tropical storms, the earliest clue to the detection of the more complicated law governing atmospheric disturbances in higher latitudes ; while his essay on the geography of plants was based on the then novel idea of studying the distribution of organic life as affected by varying physical conditions. His dis covery of the decrease in intensity of the earth s magnetic force from the poles to the equator was communicated to the Paris Institute in a memoir read by him, December 7, 1804, and its importance was attested by the speedy emergence of rival claims. His services to geology were mainly based on his attentive study of the volcanoes of the New AVorld. He showed that they fell naturally into linear groups, presumably corresponding with vast subter ranean fissures ; and by his demonstration of the igneous origin of rocks hitherto held to be of aqueous formation, he contributed largely to the spread of juster views than those then prevailing. The reduction into form and publication of the encyclo paedic mass of materials scientific, political, and archaeo logical collected by him during his absence from Europe was now Humboldt s most urgent desire. After a short trip to Italy with Gay-Lussac for the purpose of investigat ing the law of magnetic declination, and a sojourn of two years and a half in his native city, he finally, in the spring of 1808, settled in Paris with the view of securing the scientific co-operation required for bringing his great work through the press. This colossal task, which he at first hoped would have occupied but two years, eventually cost him twenty-one, and even then remained incomplete. With the exception of Napoleon Bonaparte, he was now the most famous man in Europe. A chorus of applause greeted him from every side. Academies, both native and foreign, were eager to enrol him among their members. Frederick William III. of Prussia conferred upon him the honour, without exacting the duties, attached to the post of royal chamberlain, together with a pension of 2500 thalers, afterwards doubled. He refused the appointment of Prussian minister of public instruction in 1810. In 1814 he accompanied the allied sovereigns to London. Three years later he was summoned by the king of Prussia to attend him at the congress of Aix-la-Chapelle. Again in the autumn of 1822 he accompanied the same monarch to the congress of Verona, proceeded thence with the royal party to Rome and Naples, and returned to Paris in the spring of 1823. The French capital he had long regarded as his true home. There he found, not only scientific sympathy, but the social stimulus which his vigorous and healthy mind eagerly craved. He was equally in his element as the lion of the salons and as the savant of the institute and the- observatory. Thus, when at last he received from his- sovereign a summons to join his court at Berlin, he obeyed indeed, but with deep and lasting regret. The provin cialism of his native city was odious to him. He never ceased to rail against the bigotry without religion, sesthe- ticism without culture, and philosophy without common sense, which he found dominant on the banks of the Spree. The unremitting benefits and sincere attachment of two well-meaning princes secured indeed his gratitude, but could not appease his discontent. At first he sought relief from the " nebulous atmosphere " of his new abode by frequent visits to Paris ; but as years advanced his excur sions were reduced to accompanying the monotonous " oscillations " of the court between Potsdam and Berlin. On the 12th of May 1827 he settled permanently in the Prussian capital, where his first efforts were directed towards the furtherance of the science of terrestrial magnetism. For many years it had been one of his favourite schemes to secure, by means of simultaneous observations at distant points, a thorough investigation of the nature and law of " magnetic storms " a term invented by him to designate abnormal disturbances of the earth s magnetism. The meeting at Berlin, September 18, 1828, of a newly-formed scientific association, of which he was elected president, gave him the opportunity of setting on foot an extensive system of research in combination with his diligent personal observations. His appeal to the Russian Government in 1829 led to the establishment of a line of magnetic and meteorological stations across northern Asia ; while his letter to the duke of Sussex, then (April 1836) president of the Royal Society, secured for the undertaking the wide- basis of the British dominions. Thus that scientific con spiracy of nations which is one of the noblest fruits of modern civilization was by his exertions first successfully organized. In 1811, and again in 1818, projects of Asiatic explora tion were proposed to Humboldt, first by the Russian, and afterwards by the Prussian Government ; but on each occasion untoward circumstances interposed, and it was not until he had entered upon his sixtieth year that he resumed his early role of a traveller in the interests of science. Between May and November 1829 he, together with his chosen associates Gustav Rose and Ehreuberg, traversed the wide expanse of the Russian empire from the Neva to the Yenesei, accomplishing in twenty-five weeks a distance of 9G14 miles. The journey, however, though carried out with all the advantages afforded by the immediate patronage of the Russian Government, was too rapid to be profitable. Its most important fruits were the correction of the preva lent exaggerated estimate of the height of the Central-Asian plateau, and the discovery of diamonds in the gold-washings of the Ural a result which Humboldt s Brazilian ex periences enabled him to predict, and by predicting to secure. Between 1830 and 1848 Humboldt was frequently employed in diplomatic missions to the court of Louis Philippe, with whom he always maintained the most cordial personal relations. The death of his brother, Wilhelm von Humboldt, who expired in his arms, April 8, 1836, saddened the later years of his life. In losing him, Alexander lamented that he had "lostlialf himself." The accession of the crown prince as Frederick William IV., on the death of his father, in June 1840, added to rather than detracted from his court favour. Indeed, the new king s craving for his society became at times so importunate as to leave him only some hours snatched from sleep for the prosecution of his literary labours. It is not often that a man postpones to his seventy-sixth
year, and then successfully executes, the crowning task of
