64a ' JPHILOSQPHICAL TRANSACTIONS. [aNNO 1748. 



C, after the names of such persons from whom they first appear to have been 

 taken, adding also the name of Cotes at length, to such others as Dr. D. has not 

 met with elsewhere, and which he therefore takes to have been transcribed from 

 the memoranda of his own experiments. This table of Mr. Cotes's used first 

 to be given in ms. to those who attended his lectures; but it was afterwards 

 printed in a single sheet, relating to a course of experiments at Cambridge in 

 1720, and since in Mr. Cotes's Hydrostatical and Pneumatical Lectures, when 

 they were published at large in 8vo by his successor Dr. Smith, afterwards master 

 of Trinity College. In these printed lectures were inserted the gravities of human 

 blood, its serum, &c. from Dr. Jurin, instead of those that had before been made 

 use of from Mr. Boyle. 



Mr. Francis Hauksbee, secretary to the Royal Society, did, about the year 

 1710, begin, in conjunction with Mr. Whiston, who had then newly left the 

 university, to give hydrostatical lectures, &c. in London; for the purpose of 

 which he reprinted in a thin volume in 4to, in which are the schemes of his 

 experiments, Mr. Cotes's table of specific gravities abovementioned. To which 

 he added, from trials of his own, the weights of steel, soft, hard, and tempered, 

 which are printed with his name in the following tables, as are also some other 

 experiments, which he has since occasionally made, and communicated to Dr. 



D. Mr. Cotes's table, with the abovementioned additions of Mr. Hauksbee, 

 was afterwards again published by Dr. Shaw, in his abridgment of Mr. Boyle's 

 Philosophical Works, at London, 17^5, 4to, vol. ii, p. 343. 



John Freind, m. d. at the end of his Praelectiones Chemicae, printed at London 

 n 1709, Svo, has published some new tables of the specific gravities both of solid 

 and fluid bodies, entirely taken from his own original experiments. And as these 

 tables contain an account of a very useful set of bodies, on which tew or no 

 other experiments have been made, it is great pity that this truly learned and 

 elegant writer was not more accurate in his trials than he appears to have been. 

 Many of his experiments having indeed been made in so lax and improper a 

 manner, and so many errors having been committed in them, that we cannot 

 with security depend on these tables, though containing otherwise facts one would 

 «o much desire to be truly informed about. Dr. D. has however here inserted 

 the several particulars of his last two tables, which immediately concern specific 

 gravities, after correcting such errors in calculation as he could certainly 

 come at. 



James Jurin, m. d. and several years secretary to the Royal Society, gave, in 

 N° 361 of the Philos. Trans, anno 1719, some original and very accurate expe- 

 riments made by himself, on the specific gravity of human blood, at several 

 times during the 6 preceding years. These were accompanied with a very curious 

 discourse, which has since been translated by himself into Latin, and reprinted 



