Thence to White-Hall, where in the Dukes chamber the King came and stayed an hour or two, laughing at Sir W. Petty, who was there about his boat, and at Gresham College in general … Gresham College he mightily laughed at for spending its time only in weighing of ayre, and doing nothing else since they sat.
William Petty was a fascinating character who is remembered variously as a pioneer in demography and political economy, the man responsible for the first really good map of Ireland and, as we see him here, the designer of a novel ”double-bottomed boat” (i.e., a catamaran). Pepys’ editors—who have a great line in dry commentary—chime in with a footnote:
The gibe was of course untrue, and in any case this laughable weighing of air did in fact lead (by way of Newcomen’s steam-engine in Anne’s reign) to the development of steam power. Cf. the similar complaint of a pamphleteer in 1680: “We prize our selves in fruitless Curiosities; we turn our lice and Fleas into Bulls and Pigs by our Magnifying-glasses; we are searching for the World in the Moon with our Telescopes; we send to weigh the Air on the top of Teneriffe … which are voted ingenuities, whilst the Notions of Trade are turned into Ridicule or much out of fashion”.
We also learn that the French Ambassador, “in a despatch to Louis XIV of 25 January/4 February, referred to Petty’s double-bottomed ship as ‘la plus ridicule et inutile machine que l’esprit de l’homme puisse concevoir.’”