Collation: 8vo: b² (b1 + A⁸ a⁸) B–Q⁸ R⁴, 150 leaves, pp. [36] 247 [1] (last page blank). A3 signed A4, b2 signed b. Title in red and black enclosed in double rules, diagram on p. 119 made up of rules.
Plates: 3 folding engraved plates: unnumbered, containing figs. 1–24, with page references (bound as throwouts at the end).
Condition: 167 x 103mm. Short tears in the folds of the plates repaired on the verso.
Binding: Contemporary dark calf, double gilt filet borders to sides with small corner tools, gilt ruled flat spine, original red morocco lettering piece, red and green sprinkled edges, printer’s waste as front pastedown, no rear pastedown. Head of spine rubbed, joints rubbed and cracked at the foot with loss of small portions of the leather, lower 40mm of backstrip glued down, corners worn.
Provenance: Contemporary signature ‘Geo: Chadwicke’ on title.
References: Fulton 72; Wing B3985; Madan 2738; ESTC R17464.
Price: £4,500

First edition. The book was in the press by November 1665 and a copy presented to the Royal Society on 14 March 1666. This is the only English edition; a Latin edition, which is rare, was printed in Oxford in 1669, followed by several continental editions.
¶ Boyle’s hydrostatic experiments added to his growing reputation as the leading philosopher of his day, exciting Pepys’ admiration and Henry More’s criticism in his Enchiridion metaphysicum (1671). This work is often referred to as a prime example of Boyle’s experimental method.
‘Although Boyle’s reputation in experimental physics rests on his pneumatic experiments, he also worked in the related field of hydrostatics. His Hydrostatical Paradoxes (1666) is both a penetrating critique of Pascal’s work on hydrostatics [ Traitéz de l’équilibre des liqueurs et de la pesanteur de la masse de l’air, 1663], full of acute observations upon Pascal’s experimental method, and a presentation of a series of important and ingenious experiments upon fluid pressure.’ (Marie Boas Hall, DSB 2, 378a)
‘Like many of Boyle’s researches the Hydrostatical Paradoxes resulted from the perusal of a recently published book. ‘Monsieur Paschall’ had written a ‘small French book’, the treatise of the ‘ Aequilibrium of Liquids’, and Boyle had been asked by the Royal Society to read and report upon it. He deals rather shortly with his author and then proceeds to describe at length the experiments which convinced him of the fallacies of his French contemporary. Boyle points out, among other things, that since pressure in a liquid is transmitted equally in all directions, divers need not fear the greatest depths. To make quite certain that excessive water pressure was not harmful he placed young tadpoles, so tender that they seemed ‘but organiz’d Gelly’, into his container and caused a pressure equal to that of a cylinder of water 300 feet in height to be brought upon the fluid; the tadpoles seemed to shrink slightly, but swam as before and showed no evidence of injury when the pressure was released. The celebrated experiments ‘that water may be made as well to depress a Body lighter then it self, as to buoy it up’ are recorded in Paradox 8, pp. 160 et seq. The observation is still made in much the same fashion by every student in his ‘practical’ courses in physics.’ (Fulton p. 52)