A detailed biography of Alexander von Humboldt can be found at Wikipedia, and a briefer one at ThoughtCo. He was born in Germany, in 1769, into a prominent Pomeranian family, his father being an officer in the Prussian army. He enrolled in various universities, before undertaking geology at the Freiberg technical university, where he studied under the famous geologist A G Werner. In 1792, when still only 22, he was appointed government mines inspector in Franconia, Prussia. Five years later, his mother died leaving him a wealthy man, and he soon set about planning a major expedition to Latin America with a French botanist, Aime Bonpland.
For five years, from 1799 to 1804, the two explored over 6,000 miles of Central and South American territory, collecting plant samples, meteorological observations and information on the earth’s geomagnetic field. On his return to Europe, Humboldt remained in Paris to write and publish 30 volumes of information accumulated during the expedition, creating a work that, Wikipedia says, ‘may be regarded as having laid the foundation of the sciences of physical geography and meteorology’.
In 1827, Humboldt returned to Berlin and took up teaching, tutoring the Prussian crown prince and lecturing on physical geography at the university. In 1829, he travelled through Siberia, at the invitation of the Russian government, to visit the gold and platinum mines. The later years of his life were devoted to studying magnetism, and to writing Kosmos. This latter work (five volumes, the last of which appeared posthumously) was focused on physical geography and the natural sciences, and tried to unify the various branches of scientific knowledge. He died on 6 May 1859, one and a half centuries ago today.
Humboldt certainly wrote diaries on his travels in Latin America. Ulrike Leitner has a note about them on the University of Potsdam website. She says that in compiling his diary, Humboldt considered ‘all observations worthy of writing down, but his preference for precise measurements [was] especially remarkable’. Humboldt’s diaries, she believes, are ‘the essential source for a full account of his stay in Mexico’ since an unfinished work on his American journey (published in French in three volumes as Relation Historique du Voyage aux Régions Équinoxiales du Nouveau Continent) ends with his arrival in Columbia in 1801. She explains that Humboldt referred to his diaries regularly and made them ‘the basis of his publications on the results of the American journey, especially for the Relation Historique’. He later took the diary notebooks apart and had them bound into nine volumes.
Leitner gives one example from Humboldt’s diary, dated August-September 1803: ‘[it was one of the] most exhausting periods of my life. I climbed all mountains using my barometer. In Valenciana I descended three times to the bottom of the mine, two times in Rayas, in Mellado, in Fraustros, in Animas and in San Bruno. I visited the mine of Villalpando, spent two days in Santa Rosa and in Los Álamos [. . .] I had a dangerous fall on my back in Fraustros, and experienced extreme pain for 14 days due to a sprain of the base of my spine!’
Elsewhere on the same university website is a short conference paper brief by Michael Zeuske of the University of Cologne. It focuses on the Diario Habana 1804, Humboldt’s last unpublished diary, and was written during or soon after the Haitian revolution. Zeuske is particularly concerned with Humboldt’s attitude to slavery and some conflicts between the stance he always takes when writing in his diary and the actual relationships he has with slaveholding elites in Cuba and Venezuela.
These references apart, I can find little evidence of Humboldt’s diaries on the internet, and I can find no sign of them ever having been published in English. However, his letters are a different matter. A large collection written to his friend Varnhagen von Ense were published (by Rudd & Carleton, New York) the year after his death with a selection of extracts from Varnhagen’s diary about Humboldt.
A short preface written by Humboldt’s niece, Ludmilla Assing, says: ‘The following letters of Humboldt furnish a contribution of the highest importance to the true, correct, and unveiled representation of his genius and character. That they should be delivered to publicity after his death was his desire and intent, which have found their positive impression in the words preceding this book as its motto. Never has he spoken out his mind more freely and sincerely, than in his communications with Varnhagen, his old and faithful friend, whom he esteemed and loved before all others. . . The interest of Humboldt’s letters is sometimes pleasantly heightened by entries in Varnhagen’s diary - they will indicate the verbal sentiments of Humboldt in addition to those written by him.’
Here are a few of Varnhagen’s diary observations about Humboldt taken from the book - Letters of Alexander von Humboldt to Varnhagen von Ense from 1827 to 1858 with extracts from Varnhagen’s Diaries, and Letters of Varnhagen and other to Humboldt - which is freely available at Internet Archive and other websites.
3 May 1837
‘In the evening, at the Princess of Pueckler’s, the long-promised lecture by Herr von Humboldt. The lecture was very fine, and made an excellent impression. I had a conversation with General von Ruhle on Humboldt’s genius. He totally agreed with me, saying, ‘When he shall have died, then only shall we understand well what we have possessed in him.’ ’
19 April 1839
‘I saw Humboldt to-day, who told me many things, and showed me a beautiful portrait of Arago, which pleased me very much. He talked much about the difficulties between Russia and England, as to their interests in the East Indies and in Persia, and repeated what he had heard about it from the Russian Emperor himself. The Czar was in a great passion against the English, and thought it highly important to oppose their supremacy in Asia. Humboldt agrees with me that the English have nothing serious to fear for the next fifty years from Russia in the Indies, but that fear and jealousy may engender a quarrel in Europe prior to any conflict in the East, although conflicting parties will certainly think twice before allowing it to come to that pass.’
9 June 1839
‘Humboldt agrees with me in the assertion made by me at different times, that too much cannot be inferred from the silence of the historians. He refers to three highly important and undeniable facts, which are not mentioned by those whose first duty it should have been to record them. In the archives of Barcelona, no vestige of the triumphal entry held there by Columbus; in Marco Polo, no mention of the Chinese wall; in the archives of Portugal, nothing of the travels of Amerigo Vespucci, in the service of that crown.’
30 April 1841
‘Humboldt has a great many enemies, as well amongst the savans as at court, who are constantly seeking an opportunity to malign him, but the moment he is praised all vituperation ceases for it is all vituperation. It is seldom that anybody is able to maintain it. Some time ago a gentleman said to me, that he did not know what to think of Humboldt, and that he could not come to a conclusion concerning him. I answered: ‘Think always the best of him, believe him always capable of the best action, and you always will be nearest the truth.’ Another said, same day, sneeringly: ‘Humboldt was a great man before he came to Berlin, where he became an ordinary one.’
4 July 1857
‘Yesterday Humboldt spoke of the time when he lived in a house at the side of George’s Garden, and was so assiduous in his magnetic observations that he once stinted himself of sleep for seven successive days and nights in order to examine the state of things every half hour; after that he changed the watch with substitutes. This was in 1807, just fifty years ago. I often saw the little house in which the experiments were made, when I visited Johannes von Mueller, who also lived in a house at the side of the same garden; or Fichte who lived in a garden house in the middle of the garden. When old George, a wealthy distiller, showed the garden to his friends, Humboldt went on to say, he never failed to boast of ‘his learned men’. ‘Here I have the famous Mueller; there is Humboldt, and there is Fichte, but he is only a philosopher, I believe.’
(Postscript: Many of Humboldt’s travel journals can now be found online thanks to edition humboldt digital; and there is also much information about his American travel journals, as well images of various pages, at the