80 LESLIE. 



pressions of Cold transmitted from the Higher Atmosphere ; with a 

 Description of an Instrument to Measure them.' The aethrioscope 

 was the instrument here alluded to. 



In 1819, upon the death of Play fair, Leslie was called to the chair 

 of Natural Philosophy, when his first care was directed to the ex- 

 tension of the apparatus required in the more enlarged series of 

 experiments which he thought necessary for the illustration of the 

 course. " This, indeed," says his biographer, Mr. Napier, " was an 

 object of which he never lost sight; and it is due to him to state, 

 that, through his exertions, the means of experimental illustration 

 in the Natural Philosophy class were for the first time made worthy 

 of the place." 



In 1823 he published, chiefly for the use of this class, his ' Elements 

 of Natural Philosophy,' a second edition of which was published in 

 1829, with corrections and additions. Besides the above-mentioned 

 works, Leslie wrote the following : ' Elements of Geometry, Geo- 

 metrical Analysis and Plane Trigonometry,' in 1809 ; ' Observations 

 on Electrical Theories,' published in 1824, in the ' Edinburgh Philo- 

 sophical Journal ; ' also many articles in the ' Edinburgh Review ; ' 

 and the articles on Achromatic Glasses ; Acoustics ; Aeronautics ; 

 Andes ; Angle and Trisection of Angle ; Arithmetic ; Atmometer ; 

 Barometer ; Barometrical Measurements ; Climate ; Cold and Con- 

 gelation ; Dew ; Interpolation ; and Meteorology, in the seventh 

 edition of the ' Encyclopaedia Britannica.' 



Early in the year 1832, on the recommendation of Lord Brougham, 

 then Lord High Chancellor, Leslie was created, along with several 

 other eminent men of science, a Knight of the Guelphic Order. He 

 was also a member of the Royal Society of Edinburgh, and in 1820 

 had been elected a corresponding member of the French Institute. 

 During the month of October, whilst engaged in superintending 

 some improvements on his grounds, he caught a severe cold, which 

 was followed by erysipelas in one of his legs, and his neglect of 

 this, owing to a contempt for medicine, and great confidence in his 

 own strength and durability, resulted in his death, at Coates, in the 

 November following, at the age of sixty-six. 



Sir John Leslie has been described as rivalling all his contem- 

 poraries in that creative faculty which discovers, often by an intuitive 

 glimpse, the hidden secrets of nature ; but possessing in a less degree 

 the powers of judgment and reason, being thus often led in his 

 speculations to results glaringly inconsistent. His exquisite instru- 

 ments, and his experimental combinations, will, however, ever test 

 the utility, no less than the originality of his labours, and will 

 continue to act as aids to farther discovery. Encyclopaedia Britan- 

 nica, Eighth Edition. Abstract of Memoir of Sir John Leslie, by 

 Macvey Napier, English Cyclopaedia. London, 1856. 



