Humboldt's First Book (1790)
Mineralogische Beobachtungen über einige Basalte am Rhein. Braunschweig: Schulbuchhandlung, 1790. 126 p.
Mineralogische Beobachtungen was Humboldt's earliest published book. Its focus was the basalt rocks of the Rhine River Valley. The author signed the title page of the Academy's copy.
