science · 12 April 1829 · 195 years ago
In 1829, the explorer-naturalist Alexander von Humboldt, age 59, began a scientific expedition to uncharted regions of Siberia at the invitation of Tsar Nicholas who also financed the journey. Humboldt crossed Asia, from Russia and Siberia to Mongolia. He recorded temperatures and noted that temperatures varied at the same latitude in accordance with distance from the ocean. As temperature data was collected from a series of Russian weather stations, von Humboldt constructed a world map of temperature, being an early use of isotherms, which he found did not neatly follow latitude. From this he developed the theory of continentality. The expedition ended on 28 Dec 1829. His 3-volume work on Asie Centrale was published several years later.
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