Georges Fournier

Georges Fournier: The Jesuit Who Wrote the Sea

For five years between 1636 and 1641, a French Jesuit priest sailed with the royal fleet in the Atlantic and the Mediterranean while it fought the Spanish. He was there as a chaplain, to say Mass and hear confessions. He came ashore having assembled, in his head and his notebooks, the material for the first encyclopaedia of the sea ever published in French. *Hydrographie* appeared in 1643, ran to more than seven hundred pages across twenty books, was dedicated to Louis XIII, and remains — as its modern reprint publishers put it — "a prime source for the history of the navy during the first half of the seventeenth century."

Caen, and a Late Vocation

Georges Fournier was born on 31 August 1595 in Caen, in Normandy, the son of a professor of law. It was a household of the educated provincial bourgeoisie, and he received the classical training that went with it. He did not, however, enter religion young. He was twenty-four when he joined the Society of Jesus at Tournai — a comparatively late vocation, and one that suggests a man who had already had time to acquire interests of his own before submitting them to an order famous for putting exactly such interests to work.

The Jesuits were, by the early seventeenth century, the most formidable teaching organisation in Europe, and their colleges took mathematics seriously at a moment when many universities did not. Fournier taught humanities and mathematics in that system. Had nothing else happened, he would have left behind a competent teaching career and perhaps a textbook.

The Chaplain at Sea

What happened was Richelieu. The cardinal's programme of naval expansion transformed France from a negligible sea power into a state with fleets in two seas, and the fleets needed chaplains. In 1633 Fournier entered the service of Henri de Sourdis, Archbishop of Bordeaux, who commanded French naval forces; from 1636 to 1641 he was at sea aboard ships of the line during the campaigns against Spain. He saw both theatres, Atlantic and Mediterranean, which turned out to matter enormously for what he wrote.

A chaplain is not a navigator, and Fournier's authority did not come from command. It came from something rarer: he was a trained mathematician who spent five years living among working seamen, watching how they actually did things and possessing the technical vocabulary to describe it. Almost nobody in seventeenth-century Europe occupied both worlds at once. The officers could sail but not systematise; the mathematicians could systematise but had never been wet.

Hydrographie

The book that resulted in 1643 is startling in its ambition. Its twenty books treat winds and tides, the operation of ports, fishing, maritime commerce, shipbuilding technique, the conduct expected of officers, and military command at sea, alongside the theory and practice of navigation itself. The 1667 edition ran to 738 pages, illustrated with diagrams, plans, maps and drawings. It was, in the words of the Université de Caen's maritime dictionary project, "la toute première encyclopédie de marine" — the very first encyclopaedia of the navy.

Its most radical section was on ship design. Seventeenth-century shipbuilding was a craft transmitted by apprenticeship and adjusted by trial and error; hulls were shaped by rule of thumb and the memory of what had floated before. Fournier attempted to supply a scientific foundation for it. He did not succeed in any modern sense — the mathematics of hull form would not arrive for another century — but the attempt itself marked a change in what a shipwright's knowledge was thought to be.

The Words of the Sea

One feature of *Hydrographie* has proved unexpectedly durable: its glossary of marine terminology. Fournier recorded not just the vocabulary but its variation, noting where Atlantic and Mediterranean seamen used different words for the same object — *agrès* on the ocean coast against *sartie* in the south. This is the instinct of a linguist as much as a mathematician, and it has made him the acknowledged precursor of the modern maritime dictionary, and an irreplaceable witness for historians of the French language of the sea.

The Other Books

Fournier was prolific across the mathematical sciences. He published *Commentaires géographiques* in 1642, a *Traité de la sphère* in 1643, a *Traité de géométrie* in 1644, and a *Traité des fortifications ou Architecture militaire* in 1649; his *Asiae nova descriptio* appeared posthumously in 1656. He died on 13 April 1652. His work travelled: it was translated into Dutch, Spanish, German and English, and *Hydrographie* was reprinted in 1667 and 1679, and again in a modern facsimile in 1973.

Why Georges Is Called a Genius

The case for Fournier rests on a specific and unusual cognitive act: the systematisation of tacit knowledge. Every trade in seventeenth-century Europe ran on skills held in the hands and heads of practitioners who could not write them down and often could not read. Fournier's achievement was to go and live inside one such trade, for five years, with a mathematician's training intact, and then produce an ordered account of the whole of it — architecture, navigation, commerce, fishing, discipline, command, even vocabulary — in a single structure. That requires two capacities that rarely coexist: the humility to take seamen seriously as sources of knowledge, and the analytical nerve to impose an encyclopaedic order on what they knew. That *Hydrographie* was still being reprinted three centuries later, and is still cited as a primary source by naval historians, is evidence that the order he imposed was a good one.

The counter-case must be granted. Fournier discovered nothing. There is no theorem, instrument, method or measurement that bears his name, and his attempt to give ship design a scientific basis did not produce the science it reached for. His mathematical treatises — on the sphere, on geometry, on fortification — were competent works of the Jesuit teaching tradition rather than original contributions. Much of what makes *Hydrographie* valuable today is the accident of being an unusually thorough observer at an unusually thin moment in the documentary record. He was a compiler of the first order and an organiser of genius; he was not a discoverer, and it would flatter him falsely to say so.

Legacy

Fournier stands at the head of two French traditions. One is technical: the sequence of hydrographic and naval-architectural literature through which France, over the following century, became the European leader in the science of ship design. The other is lexicographic: the maritime dictionary, which begins with his glossary. And for anyone attempting to reconstruct what Richelieu's navy actually was — how it sailed, fought, ate, paid and spoke — the priest from Caen who went to sea to save souls remains the indispensable witness.

Achievements

• Recorded as mathematician, geographer and engineer