70 ALEXANDER VON HUMBOLDT. 



Humboldt remained in attendance on the king through- 

 out the journey, accompanying him to Berlin by way of 

 the Tyrol and Bohemia. He had not seen his native city 

 since the year 1807, and he received the most gratifying- 

 attentions from his numerous friends during the few months 

 of his stay. He particularly enjoyed intercourse with his 

 brother William, who was now living in retirement at the 

 family residence at Tegel, in the improvement and adorn- 

 ment of which he took the greatest interest. At a meeting of 

 the Academy of Sciences, on January 23, 1823, Humboldt gave 

 a lecture upon 'the Formation and Action of Volcanoes in 

 various parts of the Grlobe,' suggested by the investigations he 

 had made at Vesuvius. The unfinished condition of his great 

 work called him again to Paris, where he spent three years in 

 uninterrupted labour, enlivened by the society of the eminent 

 men of science congregated in the French capital. 



At length, at the renewed instance of the king, he de- 

 termined to leave Paris and take up his residence at Berlin. 

 Towards the close of 1826, he entered upon preliminary ar- 

 rangements, returning to Paris for a short while, to superintend 

 ,the packing up of his instruments and collections, and to take 

 leave of his friends ; to whom he was glad to be able to hold 

 out the prospect of a speedy reunion, since he had received 

 permission to revisit Paris at stated intervals. 



In February, 1827, he bade adieu to Paris, and started for 

 London in company with Baron von Billow, recently appointed 

 Ambassador at the Court of St. James's, who, in 1821, had 

 married Humboldt's niece Grabriele. From England he pro- 

 ceeded by way of Hamburg to Berlin, where he arrived in 

 April, henceforth to live and work in happy union with the 

 brother to whom he was so strongly attached. 



He continued to regard Paris as the true metropolis of 

 science, where he never failed to meet with subjects suited to 

 the grasp of his mighty intellect, and where he ever found a 

 stimulus to labour. So late as 1847, at the age of 78, he 

 wrote to Bunsen from Berlin in prospect of a visit to Arago : 

 'My visit to Paris will not only afford me some amount 

 of necessary relaxation, for here I am the most besieged 

 inquiry-office in the country, but it will also supply me with 





