Biographical Memoir of Sir John Leslie. 17 



summated.* We happened to witness this consummation, — aX 

 least the performance of the first successful repetition of the 

 process, — and we never shall forget the joy and elation which 

 beamed on the face of the discoverer, as, with his characteristic 

 good nature, he patiently explained its principles, and the steps 

 by which he had been led to it. We could not but feel, on 

 looking at, and listening to him, how noble and elevating must 

 be the satisfaction derived from thus acquiring a mastery over 

 the powers of Nature, and enabling man, weak and finite as he 

 is, to reproduce at pleasure her wondrous works ! Proportioned 

 to the admiration which such achievements are calculated to ex- 

 cite, ought to be the disapprobation of any unfair endeavours 

 to lower or depreciate them. We have already alluded to an at- 

 tempt to divest this illustrious experimentalist of the honours 

 connected Avith his Differential Thermometer ; and we have 

 now to add, that several years after the discovery of his pro- 

 cess of Artificial Congelation, some similar endeavours were 

 exhibited to transfer the merit of that discovery to a person of 

 the name of Nairne. The claim for him was founded on a Paper 

 published in 1777, in the Transactions of the Royal Society of 

 London ; from which it appears that he was acquainted with 

 the facts, that evaporation produces cold, and that sulphuric 

 acid, the absorbent employed by Mr LesHe, imbibes moisture. 

 But, in order to decorate Mr Nairne with the laurels of the 

 latter, his depredators ought to have been able to shew, that 

 the former had actually combined the properties alluded to, in a 

 manageable process for the production of ice ad libitum. In such 

 an attempt they must have failed ignominiously ; and, perhaps, 

 there is not in the whole history of science any more triumph- 

 ant reply to a charge of plagiarism, than is furnished by the 

 admitted facts, that with Mr Nairne's Paper before it for a 

 long course of years, the scientific world remained utterly ig- 

 norant of the existence of any such process till the date of Mr 

 Leslie's discovery ; — nay, that with his description of that pro- 

 cess in their hands, the most distinguished experimentalists of 



* See the article Cold in the Encyclopcedia Britannica. The successive steps 

 of the discovery are here recited by himself, in those verba anlentia which the 

 bent of his genius so strongly prompted him to employ. 



vol,. XXI II. NO. XLV. — JULY 1837. B 



