Good Housekeeping

Steven Shapin

  • William Petty and the Ambitions of Political Arithmetic by Ted McCormick
    Oxford, 347 pp, £63.00, September 2010, ISBN 978 0 19 954789 0

In 1667, the Royal Society’s first historian described the early Restoration as ‘this Age of Experiments’. He was advertising the society’s new scientific programme and he was making a joke. One of the society’s most prominent members had designed and built a new sort of ship – a ‘Double-Bottomed’ vessel, a kind of catamaran – intended to require less draught, to sail faster and with a smaller crew than anything then at sea. It was meant to be a world-changing technology, revolutionising trade and naval warfare. The designer was the polymathic William Petty (1623-87) – mathematician, mechanic, physician, cartographer and statistician – and one of his prototypes was called the Experiment.

The ship was an experiment in science, technology and entrepreneurship. No one had ever seen such a vessel; it violated the conventions of the shipwright’s art; and among the knowledgeable it was generally an object of ridicule and opposition. There was, Petty acknowledged, ‘scarce a good word for it’ from anyone in the business. Most experts thought it wouldn’t work, and some worried that, in the unlikely event it did, it would be a technology too far. Samuel Pepys, the Navy Board’s clerk of the acts, was a supporter, while the master shipwright Anthony Deane said Petty’s design ‘must needs prove a folly’. The navy commissioner Peter Pett told Pepys that the double-hulled ship was ‘the most dangerous thing in the world’: if it was successful, the secret would get out, and it would be the ruin of English trade and sea power. The Dutch, with whom England was about to fight the second instalment of a series of naval wars, might use the shallow-draught ship to sail right up the Thames and lay London waste.

Petty’s entrepreneurship was at once scientific, economic and political. Shortly after the Royal Society was founded in 1660, its leaders asked Petty and Christopher Wren ‘to consider the philosophy of shipping’, and the king himself urged Petty to turn his mind to naval matters. The mix of science and statecraft was compelling: Petty got down to work straight away. He wrote to the king, saying that ‘there was no greater, no more stately … nor more intricate engine in the World than a Ship,’ and that advances in naval technology would be a great experiment in mechanical philosophy, an exercise ‘in the whole Doctrine of Number Weight & Measure’. Petty’s Experiment was meant to be a ship of state. His plan was to translate new science into a new ship and a new ship into enhanced state power. These were, literally, transformations of ‘state’ and not of substance.

The double-bottomed ship was from the start intended to be a public-private partnership: Charles II initially gave it vocal support but no money; Petty ventured some of his own funds; Viscount Massereene, a big Irish landowner, put in some more. The Royal Society, which was itself still hoping for Crown subvention, appointed an elite committee, including naval administrators, to perform due diligence on the initial designs. But it declined to take over research and development work, pointing to an ambiguous boundary between what belonged to science and what to the Crown: ‘The matter of navigation being a state concern was not proper to be managed by the society.’ Science was thought to end at the point it became folded into statecraft.

Petty’s invention was a gamble. The first small-scale sailing version was constructed in Ireland in 1662 and he tried to cover some of his investment by wagering on a race in Dublin Bay between his double-hulled vessel and all comers. Other prototypes were built and sailed between Dublin and Holyhead; more wagers were made, and won, by Petty. Finally, he brought it to the Thames and recklessly offered ‘to take odds against the king’s best boats’. But Charles had by then soured towards the project – and on the Royal Society’s utilitarian promises in general – and Pepys recorded that ‘the king would not lay.’ Though Charles wouldn’t subscribe, Petty formed a syndicate to back his third, and largest, double-bottomed ship. The Experiment was launched in the Thames just before Christmas 1664. It sailed to Portugal in April the following year; in October it set out on the return journey to England but encountered a storm in the Bay of Biscay and sank with the loss of all hands.

Petty was an optimistic entrepreneur: ‘This adversitie will fire and steady the resolution … I am not much discouraged.’ He solicited backing for another version, but it was a long time before he could persuade investors to try again. Almost 20 years later, neither the nautical Duke of York nor the Royal Society, then presided over by Pepys, was keen, but Petty put together a syndicate with a large, mainly Irish group of subscribers and launched yet another double-bottomed ship in 1684. This proved seriously defective – ‘she performed soe abominably, as if Built on purpose to disapoint,’ one observer wrote – and Pepys now offered to bet against its eventual success. That was the end of Petty’s experiments in the natural science and technology of shipbuilding. It was reckoned that he had spent £1500 of his own money and £3500 of his friends’, and three years later he was dead. The project failed, Ted McCormick writes, ‘not because it was bad science or bad policy but because it fused science and policy in a way neither political nor scientific institutions were prepared to accommodate’.

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