Alexander von HUMBOLDT (1769-1859) traveller and geographer. L.A.S., Saturday, to a friend; 1 page in-12. A P.A.S. of dedication is attached: "to Mr. Letronne, loving homage of Alexander Humboldt". "I hope that this morning you will have received the little note in which I expressed my deep regrets. I dare to send the note back in the hope that you can still make someone happy "...