232 PHILOSOPHICAL TRANSACTIONS. [aNNO 1668. 



those of the labouring negroes : troublesome swellings are the consequence, which by neglect are apt 

 to degenerate into ulcers. See Catesby's Carolina, appendix, p, 10. In the Systema Naturae of 

 Linnaeus, the insect is referred to the genus pulex, under the title of piilex penetrans. See also 

 Sloane's Jamaica, introduction, p. cxxiv. 



An Account of two Boohs. N" 33, p. 640. 



I. Saggi di Natural! Esperienze fatte nell Academia del Cimento, in Firenze, 

 An. 1667, in fol. 



The book contains these particulars : — 1. An application of the instruments 

 employed in these experiments. — 2. Experiment belonging to the natural 

 pressure of the air. — 3. Concerning artificial conglaciations. — 4. About natural 

 ice. — 5. About the change of the capacity of metal and glass. — 6. Touching the 

 compression of water. — 7- To prove that there is no positive lightness. — 

 8. About the magnet. — 9. About amber and other substances of a virtue elec- 

 trical. — 10. About some changes of colours in divers fluids. — 11. Touching 

 the motions of sound. — 12. Concerning projectiles. — 13. Various experiments. 



II. Vera Circuli et Hyperbolae Quadratura, in propria sua proportionis specie 

 inventa & demonstrata, a Jac. Gregorio Scoto,* Patavii, in 4to. 



This tract, perused by some very able and judicious mathematicians, and par- 

 ticularly by the Lord Viscount Brounker, and the Rev. Dr. John Wallis, re- 

 ceives the character of being very ingeniously and very mathematically written, 

 and well worthy the study of men addicted to that science : that in it the author 

 has delivered a new analytical method for giving the aggregate of an infinite or 

 indefinite converging scries: and that thence he teaches a method of squaring 

 the circle, ellipsis, and hyperbola, by an infinite series, thence calculating the 

 true dimensions as near as you please. And lastly, that by the same method 

 from the hyperbola he calculates both the logarithms of any natural number 

 assigned, and vice versa, the natural number of any logarithm given. 



* James Gregory, a celebrated mathematician, was born at Aberdeen, 1639. He very soon dis- 

 tinguished himself by his ingenious writings and inventions in various branches of the mathematics. 

 He was the contemporary of Newton, as well as a formidable competitor in some of his discoveries, 

 as the reflecting telescopes and infinite series. After returning from his travels on the continent, he 

 became a respectable member of the Royal Society, and contributed several valuable papers to the 

 Philosophical Transactions. Mr. Gregory was engaged in some controversies with several eminent 

 philosophers, as Newton, Huygens, &c. He seems to have been of an irritable temper, and jealous 

 of his discoveries and inventions. He seems also to have been rather severe in his contemptuous at- 

 tack on the harmless Mr. Sinclair of Glasgow. Besides the before mentioned papers in the Philoso- 

 phical Transactions, he was the author of several learned works 5 as Optica Promota, 1 6"()3 ; Vera 

 Circuli et Hyperbolae Quadratura, 16675 Geometriae Pars Universalis, I668 j Exercitationes Geome- 

 tricae, 1668 ; The Great and New Art of Weighing Vanity, &c., 1672. Mr. Gregory became successively 



