Jorge Juan: the sailor and spy who discovered that the Earth was flattened at the poles

Brilliant sailor, intrepid explorer, scientist, soldier, educator and secret agent, Jorge Juan from Alicante (1713-1773) was one of the great personalities of the Hispanic enlightenment.

Oliver Thansan
Oliver Thansan
30 March 2024 Saturday 10:27
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Jorge Juan: the sailor and spy who discovered that the Earth was flattened at the poles

Brilliant sailor, intrepid explorer, scientist, soldier, educator and secret agent, Jorge Juan from Alicante (1713-1773) was one of the great personalities of the Hispanic enlightenment. His life has everything from political intrigue to mathematical calculations that were used to determine the shape of the planet and to modernize the Spanish Navy.

He lost his father when he was only three years old and his uncle took care of his education. After completing his first studies at the Jesuits of Zaragoza, he set sail for the island of Malta and became a page to the grand master of the order. At only 21 years old, he was presented with a great opportunity: the Geodesic Mission to Ecuador. It was a scientific expedition to determine the exact shape of the planet, which turned out to not be a perfect sphere, as it was flattened at the poles.

Jorge Juan was so young that they had to promote him to lieutenant, suddenly skipping several military ranks. An extraordinary adventure awaited him in which he demonstrated his talent not only for cartography, but also for military defensive tactics. Theirs was slow and arduous work, requiring a lot of patience and precision instruments. The measurements required advanced knowledge of trigonometry, astronomy and infinitesimal calculus.

After his return to Europe he would be involved in a complicated matter of industrial espionage in Great Britain, where he served his mentor, the Marquis of Ensenada, Prime Minister of Fernando VI. The Spanish government, in favor of “armed peace,” sought to modernize the navy due to the slowness of its ships. To have an alibi, Jorge Juan pretended that he only intended to exchange impressions with scientists from the Royal Society.

However, thanks to various disguises, he could acquire the personality that best suited him: Mr. Joseus, Mr. Sublevant, Mr. Fougues or Mr. Montmor. These false identities helped him visit the English shipyards and arsenals, where he drew detailed plans of the facilities and the different types of ships. In turn, he hired fifty high-level nautical craftsmen.

The plan was perfect until it fell apart due to an indiscretion. However, Jorge Juan was able to escape thanks to his expertise, facilitate the escape of his assistants and safeguard the precious plans.

The Spanish would never be able to surpass 18th century England in naval matters, but they would gain control of a fleet that any of the maritime powers wanted as an ally. Jorge Juan created his own system for manufacturing ships, which, after the fall of Ensenada, was replaced by a French method. Would Spain's naval history have been different without this unfortunate change?

To learn more about the character, Isabel Margarit, director of History and Life, and journalist Ana Echeverría propose a getaway to Novelda, near Alicante, where you can visit El Fondonet, Jorge Juan's family home, which exhibits a collection of the various books and scientific treatises of this illustrious sailor.

The Novelda Modernist Museum also houses very interesting documents, from personal letters to a diary of his diplomatic trip to Morocco. On the other hand, we can enjoy The King's Spy (Ediciones B, 2017), a novel by José Calvo Poyato about the protagonist's adventures in London.

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