6 Alexander von Humboldt. 
he delighted long after to call ‘my celebrated teacher and 
friend.’ ‘If I might,’ wrote he in Cosmos in the late evenin 
fixed desire to visit the land of the tropics, I s 
George Forster’s Delineations of the South Islands,’ ete. 
The same year, 1788, and while enjoying the society of Fors- 
ter, there appeared another little book which seems to have still 
farther aroused his love of nature and strengthened his resolu- 
which he says in Cosmos ‘ accompanied me to the climes whence 
joined his friend Forster at Mayence, whither he had removed, 
and they two set out on a private scientific Exploring Expedi- 
tion down the Rhine. At that time the great question that de- 
vided geologists, had reference to the Plutonian and Neptunian 
rigin of rocks. The Basalt of that noble river was before 
him, and accoutred as he was he plunged into the controvers 
with mind impartial and fresh from the university. Th eral 
of his investigations appeared the same year in his first book, 
at the age of twenty, entitled, Mineralogische Beobachtungen tiber 
einige Basalteam Rhein. Braunschweig, 1790, 12° i 
neat little volume arrranged with taste and judgment, and ina 
scientific point of view is said to be ereditable to a much older 
head. The book was published anonymously and is now but 
as! eae being very scarce. The copy described in the 
*. @atal and now peasy to General Frémont, 
hor’s autograph sig. 
