VOL. XXVI.] PHILOSOPHICAL TRANSACTIONS. 417 



sequently at 50 degrees below the freezing point, which I am informed is the 

 greatest degree of cold that has happened in our climate, it would be reduced to 

 126 parts of the whole, and in that state would be one 8th niore dense than 

 when at the greatest degree of our natural heat. The reason why I could not 

 prove this latter part by experiment was, that when I came to expose the ther- 

 mometer and syphon in the open air, or to the freezing mixture, the syphon 

 would instantly receive the impression of the cold, and the air contained in it 

 be considerably contracted, before the thermometer would give any sign of such 

 alteration. But seeing the former part of the experiment succeeded so exactly 

 regular, I think there can be no doubt of the truth of the whole calculation. 

 This experiment was made February the 11th, 1708; the mercury in the baro- 

 meter at the same time standing at 30 inches. 



On the Laws of Attraction and other Physical Principles. By Mr, John Keillt* 

 A.M. of Christ-church College, Oxford. N^315, p. 97. Translated from 

 the Latin. 



The three following principles are to be laid down, as the foundation of all 

 physics; viz. 1. A vacuum. 2. The divisibility of quantity in infinitum. 3. The 



* Dr. John Keill, an eminent mathematician and F. R. S. was born at Edinburgh in I67I, and 

 studied in that university, where he made great proficiency in the mathematical sciences, under Da. 

 Gregory the learned professor there, who was one of the first that had embraced and publicly taught 

 the Newtonian philosophy. In iGp^ Mr. Keill followed his tutor to Oxford, where he obtained one 

 of the Scotch exhibitions in Baliol college, but afterwards removed to Christ-church college, about 

 the year 1700. It is said that Keill was the first who taught Newton's principles, by the experi- 

 riments on which they are founded: and this it seems he did by an apparatus of his own providing; 

 by which means he acquired a great reputation in the university. The first public specimen he gave 

 of skill in scientific knowledge, was his examination of Dr. Burnet's T'heory of the Earth j with 

 Remarks on Mr. Whiston's New Theory} which appeared in I698. These theories were defended 

 by their authors} which drew from him, in l699> an Examination of the Reflections on the Theory 

 oif the Earth, with a Defence of the Remarks on Mr. Whiston's New Theory. In 1700 Mr. Keill 

 was appointed deputy professor of natural philosophy in Oxford j and the year following came out his 

 celebrated treatise, Introductio ad Veram Physicam, being the substance of his public lectures, and 

 is supposed to be the best and most useful of all his performances. This edition contained only 14 lec- 

 tures} but in the second, of 1705, he added two more: and an English edition of the same was 

 printed in 1736. 



About the year 17O8 he became F. R. S. and the same year had published in the Philos. Trans, the 

 above paper on the laws of attraction and its physical principles. About this time being offended at a 

 passage in the Leipsic Acts, calling in question Newton's right to the first invention of the method 

 of fluxions, he communicated another paper, asserting tlie justice of that claim : a circumstance 

 which occasioned some disputes with Mr. Leibnitz on that point, which terminated in favour of Mr. 

 Keill. In 1709 Mr. Keill was appointed treasurer to the Palatinates, and in that station attended 

 VOL. V. 3 H 



