HUMBOLDT, Alexander von (1769-1859). Two autograph letters signed, the first to Prince Clemens von Metternich, Berlin, 6 September 1856, reporting the partial transcription of the 'Metternich Stele', giving news of its publication and reception, and transcribing lines praising the eyes, ears and belly of the cat, with explanations of the cat's significance in Egyptian theology, 2 pages, 4to, envelope; and letter to an unidentified recipient ('Eur Excellenz'), n.p., n.d., asking the recipient to make enquiries as to whether a particular traveller ('der talentvolle Reisender') will be making his journey with the support of the Austrian, Bavarian or Brazilian government, one page, 8vo (remnants of adhesive leading to some discolouration).