1819.] Scientific Intelligence. 3 LI 



respecting them contained in the notice inserted in the August 

 number of the Annals.* 



Dr. James Playfair, Principal of St. Andrew's College, and 

 the author of the Chronology, and the Geography, was about 

 10 years older than Prof. Playfair, of Edinburgh ; of whom he 

 was a distant relation, a cousin, twice or three times removed. 

 Mr. John Playfair, Professor of Natural Philosophy in the 

 University of Edinburgh, was the son of the Minister of Liff in 

 the carse of Goury. He succeeded him as clergyman of the 

 same parish, when scarcely more than 22 years of age, and had 

 the support of his mother, and brothers, and sisters, devolved 

 upon him. He continued in the situation of a clergyman about 

 two years, when he was employed by the late Mr. Ferguson, of 

 Reith, as tutor to his son, with an annuity, equivalent to his 

 stipend as minister of Liff. In this situation he continued also 

 about two years, when, chiefly by the influence of Prof. Dugald 

 Stewart, he succeeded him as Professor of Mathematics in the 

 University of Edinburgh. His first publication, so far as I know, 

 was a paper on impossible quantities inserted in the Phil. Trans, 

 for 1778. As he is there styled the Rev. John Playfair, a desig- 

 nation which he dropped as soon as he left his living, I presume 

 that when he wrote it he was minister of Liff". His writings, a 

 few mathematical and biographical papers excepted, to be found 

 in the Transactions of the Royal Society of Edinburgh, were 

 chiefly controversial, partly on the Indian astronomy, and partly 

 on the Huttonian theory. The very high reputation which he 

 enjoyed was not owing to his writings, though they possessed 

 uncommon energy, and were distinguished by their arrange- 

 ment and their clearness, nearly so much as to his powers of 

 conversation, which were uncommonly great, and to his manners, 

 which were polished and exceedingly engaging. He was a whig 

 of the new school, and a very zealous politician. But his treat- 

 ment of his mother and brethren, who were left dependant on 

 him, and whom he supported with the utmost tenderness and 

 generosity, even when he could not very well afford it, demon- 

 strates, I think, the goodness of his heart, and the soundness of 

 his principles at bottom. 



III. Method of rendering Glass less Brittle. 



An American gentleman has transmitted to the Editors of the 

 Annales de Chimie et de Physique (vol. ix. p. 422), the follow- 

 ing method of rendering glass capable of bearing sudden changes 

 of temperature without breaking. Let the glass vessel be put 

 into a vessel of cold water, and let this water be heated boiling- 

 hot, and then allowed to cool slowly of itself without taking out 

 the glass. Glasses treated in this way may, while cold, be 

 suddenly filled with boiling-hot water without any risk of their 



• It was incautiously copied from one of the daily newspapers, anil should haT* 

 been confined to the simple statement of the Professor's lamented decease, resett- 

 ing a more detailed account of him for a future number. — Publisher. 



