OF BARON HUMBOLDT. 127 



place in the year 1820, lie had scarcely arrived, 

 when soldiers surrounded him, and took him a 

 prisoner to St. Martha, after they had first 

 destroyed the plantations. This violent act 

 was due to the revenge and the selfishness of 

 the Dictator of Paraguay, Dr. Francia. This 

 personage had long watched with a jealous eye 

 the tea plantations established by Bonpland on 

 several points of Brazil ; tea being the principal 

 article of export of that country. Bonpland was 

 detained at St. Martha, where, however, he was 

 permitted to be at large and practise as a 

 physician. 



Humboldt immediately interceded on his 

 behalf, and made representations to all his in- 

 fluential friends ; but unfortunately his inter- 

 cession produced no favourable result at Para- 

 guay. It was not until the year 1829 that 

 Bonpland regained his liberty, and returned to 

 Buenos Ay res. 



In the month of September, 1818, Alexander 

 von Humboldt arrived in London, where he met 

 his brother "Wilhelm, who at that time occupied 

 the post of Prussian Ambassador there, and who 

 had taken considerable interest in the suppres- 

 sion of piracy, and the extinction of the slave- 

 trade. Alexander appeared also in an official 

 capacity. The Allied Powers had instructed 



