VOL. VIII.] PHILOSOPHICAL TRANSACTIONS. 5/ 



water in water: new Experiments of the positive or relative Levity of Bodies 

 under water; of the Air's Spring on Bodies under water: and about the dif- 

 ferent Pressure of heavy Solids and Fluids. London, 1672, in 8vo. 



These tracts being well known to philosophers, but little need now be said 

 concerning them, especially after the long and particular title. 



In the third part, he discusses at large and solves this problem: whence it is, 

 that urinators or divers are so far from being killed or oppressed by the weight 

 of the incumbent and ambient water, that they are not so much as hurt by it. 

 Concerning which he says it is taken for granted, that divers, though at ever 

 so great a depth, feel no pressure against them by the water, which he says is- 

 an aftirmation in point of fact, of whose truth he makes some question. To 

 this hydrostatical discourse our author subjoins a letter, illustrating an experi- 

 ment to weigh water in water, on account of some exceptions made to it by 

 Mr. George Sinclair, in his hydrostatics, lately printed at Edinburgh. On which 

 occasion the editor of these papers finds himself obliged to take notice of a 

 pamphlet annexed to this book of Mr. Sinclair's, called a Vindication of the 

 Preface of the book, intitled Georgii Sinclari, &c. Ars nova et magna Gravitatis 

 et Levitatis, from the challenges and reflections of the publisher of the Phil. 

 Trans, as they are to be found in Numb. 50, Aug. 16, 1669. Not to reflect, 

 as it deserves, on the artifice of leaving this pamphlet out of the copy, that was 

 presented by Mr. Sinclair to Sir R. Moray, a person whom he knows to be very 

 far from allowing his pretences in the preface here questioned ; the editor 

 firstof all desires the reader to observe, how grossly Mr. Sinclair prevaricates in 

 his pretended vindication, when he asserts that the MS. of Ars nova et magna, 

 &c. was not committed by the author to the judgment of the Royal Society, 

 omitting the main part, contained in these words, which (recording) is yet 

 their constant and careful practice to do in all things of that nature. For if this 

 had been taken in by Mr. Sinclair, he must certainly have thought none but 

 such as are wholly ignorant of the candor and justice of that illustrious body, 

 and of the care of the sworn secretaries thereof, would believe him in what he 

 so boldly and immorally asperses them with, viz. that it was the interest of them, 

 who had taken out the purposes of his MS. to procure it should not be re- 

 corded in the register; unless it should be said that the registry had been in this 

 only case purposely omitted at the solicitation of the pretended plagiaries; and 

 who they are, has not yet been declared by M. Sinclair: who, in the next place, 

 might do well to consider, not only how much, before his pompous Ars nova et 

 magna came abroad, had been printed of the doctrine of the air's pressure, and 

 likewise how well was known the way of counterpoising air with quicksilver in 

 glass tubes; but also that in this so generally inquisitive and experimental age, 



VOL. II, I 



