1814.] Mr. Scheele. 171 



importance, are superior to those made by any other chemist that 

 has hitherto appeared. It will serve, perhaps, to convey a clearer 

 idea of this truth, if I give a list of the new substances for the 

 knowledge of which we are indebted to his fortunate sagacity : — 



1. Tartaric acid. 10. Molybdic acid. 



2. Fluoric acid. 11. Lactic acid. 



3. Chlorine. 12. Tungstic acid. 



4. Barvtes. 13. Prussic acid. 



5. Arsenic acid. 14. Sweet principle of oils. 

 G. Oxalic acid. 15. Citric acid. 



7. Uric acid. 16. Malic acid. 



8. Azotic gas. 17. Gallic acid. 



9. Sulphureted hydrogen gas. 



Thus he discovered no fewer than 17 new chemical substances; 

 the greater number of which are at this day of indispensable utility 

 to the chemist, and act a most important part in the phenomena of 

 nature. 1 have omitted in the above enumeration various important 

 discoveries, that of oxygen in particular ; because Scheele, though 

 he undoubtedly had the merit of discovering that substance without 

 any assistance, from others, was not the person who first made it 

 known to the world. 1 have omitted likewise noticing the new 

 methods of experimenting which he first introduced, and the pre- 

 cision at which he always aimed, and which he generally attained. 

 This had no little ettect upon the science, and contributed in no 

 small degree to form that analytical skill which has now become 

 pretty generally diffused among chemists. In short, if we take 

 into consideration that Scheele died when still a young man, that 

 he was destitute of a liberal education, that he spent his life in a 

 foreign country, with the language of which he was never suffi- 

 ciently acquainted to be able to write it, and that the greatest part 

 of his eareer was passed in the situation of an apothecary's assistant, 

 without any house or laboratory of his own — if all this be taken 

 into view, and compared with the number and splendour of his 

 discoveries, it will be admitted, 1 think, without hesitation, that he 

 was one of the most extraordinary men that ever existed, and one 

 ol the brightest ornaments of chemistry and of human nature. 



Article II. 

 On the Oxides of Arsenic. By Thomas Thomson, M..D. F.R S. 



'I in-; hint person who made a satisfactory set of experiments to 

 determine the proportions in which arsenic unites wub ox t gen uas 

 M. 1'roust. According to his experiments, which were published 



