380 PHILOSOPHICAL TRANSACTIONS. [aNNO 166Q, 



An Account of some Books. N" 50, p. IOI7. 



I. Georgii Sin clari * Ars Nova et Magna Gravitatis et Levitatis. Rotero- 

 dami, in 4to. An. 1669. 



The subject of this book is the spring and pressure of the air, with some 

 considerations on the weight and pressure of water ; as also concerning a 

 vacuum, the effects of pumps, and on pendulums, hygroscopes, &c. 



Whether the doctrine or experiments, here delivered, be new and unheard 

 of, as the author is pleased to think, we leave to the intelligent to judge. But 

 we find ourselves obliged to take notice that the excellent treatise of the ho- 

 nourable Robert Boyle, entitled. New Experiments Physico-Mechanical, 

 touching the spring of the air and its effects, was printed two years before that 

 time, about which the author of this book says, in his preface to the reader, 

 he came to London, and there committed his then unprinted papers to the 

 censure of the Philosophical College there, meaning the Royal Society, of 

 whom he complains in the preface, that he waited for an answer from them 

 for almost two years in vain ; adding, that he afterwards found, in divers books 

 printed in English, many things taken out of his manuscript. 



But to undeceive the reader in this particular, we shall first desire him to 

 compare the date of the edition of Mr. Boyle's book_, above-mentioned, with 



* Mr. George Sinclair, or (as it is in his printed books) Sinclar, was professor of philosophy in 

 the university of Glasgow, and author of several works on mathematical and physical subjects. He 

 was dismissed from his professorship soon after the restoration, on account of his political principles j 

 and again recalled to it on the change of government at tlie revolution in 1688, and he died 



in 1696. 



Mr. Sinclar's publications were, 1. Tyrocinia Mathematica, 12mo. Glasc. 1661 ; 2. Ars Nova et 

 Mao-na, &c. 4to. Roterod. l669; 3. Hydrostatics, 4to. Edinb. l672; 4. Hydrostatical Experiments, 

 with a Discourse on Coal, 8vo. Edinb. l680j 5. Principles of Astronomy and Navigation, 12mo. 

 Edinb. 1688. Besides which, a very extravagant production, called " Satan's Invisible World disco- 

 vered," has been ascribed to him: it bears the initials, G. S. of his name. 



Mr. Sinclar's writings are not destitute of ingenuity and research j though they may contain some 

 erroneous and eccentilc views. His work on Hydrostatics, and his Ars Nova et Magna Gravitatis et 

 Levitatis, and perhaps also his political principles, provoked the indignation of some persons, on which 

 occasion Mr. James Gregory, author of the Optica Promota, &c. and then professor of mathematics 

 at St. Andrews, animadverted on him rather severely in a treatise entitled, " The Great and New 

 Art of Weighing Vanity, &c. under the name of Patrick Mathers, Archbedal of St. Andrews." 



Considerable attention seems to have been paid by Mr. Sinclar to such branches of hydrostatics as 

 were of a practical nature j and it has been said he was the first person who suggested the proper 

 mediod of draining the water from the numerous coal mines in the south-west of Scotland. During 

 the period he was deprived of his office, he resided about tlie southern and border counties, collecting 

 and affording useful information on subjects of mining, engineering, &c. particularly he was em- 

 ployed by the magistrates of Edinburgh, on the then new plan for supplying the city with water. Sec- 



