Latitude, by Nicholas Crane

The latest book from explorer Nicholas Crane tells an incredible tale of an 18th century scientific expedition.
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First let’s deal with the elelphant in the room. Nicholas Crane’s Latitude will inevitably draw comparison with Dava Sobel’s surprise runaway best-seller Longitude, which was published over a quarter of a century ago in 1993 and has remained in print ever since. Sobel stated that she was telling the true story of a genius who solved the great scientific problem of his time. Crane is a seasoned traveller, who has walked the breadth of Europe from Cape Finisterrre to Istanbul. He is also a winner of the Mungo Park Medal and former president of the Royal Geographical society. Perhaps his greatest geographic achievement is to have  identified and visited the geographical Pole of Inaccessibility, the point on the globe that is furthest from the open sea, which lies in a remote region of north-western China.

Crane informs us that this story was ‘written under seige during the pandemic’. All the time he was writing Latitude, ‘I wanted to swap my desk for a deck and sail with scientists in search of solutions’. It is this very longing which brings Crane’s extraordinary tale so vividly to life. He wants to be taking part in all that was happening, and in so doing he plunges the reader into his hectic, fantastic adventure.

On 12 May 1735 the 650 ton Portefaix with 250 people and all manner of scientific equipment crammed aboard set sail from the western French port of Rochefort on the French Geodesic Mission to the Equator. The aim of this expedition was nothing less than to determine the shape of our planet. It had long been assumed that the earth was not a perfect sphere. In keeping with the rationalist French approach to science the philosopher René Descartes had proposed that because the earth spun like a vortex it was bound to be elongated at both poles. By contrast, Isaac Newton, using physics rather than theory, worked out that according to his new law of gravitation the earth would tend to bulge at the equator and be flattener at the poles. The French Geodesic Expedition was intended to resolve this issue. If Descartes was right, Newton’s laws of physics were wrong. This would confirm the French scientific view that the Cartesian model was the correct scientific description of how the world worked.

The expedition got off to a sorry start. Not only was the Portfaix weighed down with huge expectations for French science, but its jam-packed passengers and stuffed holds ensured that it soon became stuck on a mudbank in the Charente estuary before it had even reached the sea. And when it did finally pass the Îsle Madame and head into the open waters of the Bay of Biscay it was immediately becalmed. An ominous beginning indeed. Yet, and so it would prove, a rare moment calm on an expedition that was expected to last a couple of years or so, but instead dragged on for well over a decade, with only a percentage of its members returning to Europe alive.

Crane’s Latitude recounts a fantastic yarn, filled with all manner of adventures. Impenetrable jungles, duels, scientific heroism and unlikely derring dos – from an Academician presenting a prostitute with a fabulous diamond to several major discoveries, such as quinine to cure malaria, and the secret of how to tap the sap from rubber trees. Crane’s book is both a great read and a highly illuminating piece of history. Not to be missed by anyone interested in anything from navigation to the early exploration of South America, from the history of science to the history of human folly. To say nothing of the sheer heroism involved in what many see as the world’s first great scientific expedition.

Latitude by Nicholas Crane is available now. You can read about the physical demands of the search for Latitude in an article from Nicholas here.

Paul Strathern is the author of Rise and Fall: A History of the World in Ten Empires. The Florentines is his latest book.