772. ALEXANDER VON HUMBOLDT (1769-1859) German naturalist and traveler who undertook scientific expedition to Asia and South America and is the eponym of the equatorial current. Scarce A.L.S. "A. v. Humboldt" in German, 1p, 8vo., [n.p., n.d.], to a friend and colleague, in part: "...Abiel Bleibt will stay with me tomorrow...and I know that I couldn't give him a greater pleasure than if you would be so kind to come and dine privately with him...". Weak fold edges reinforced on verso with archival tape at margin, otherwise in very good condition. $700 - 900