NOTES. 511 



should be written with such remarkable carelessness, and 

 such manifest inattention to the facts. To find mistakes so 

 very gross in the works of ordinary writers might excite little 

 surprise; but when they are embodied in the history of the 

 National Institute, and when they come to us under the 

 name, among the very first in all sciences, of Cuvier, we may 

 at once wonder and mourn. 



Since the Life of Watt was published, a very strange attack 

 on both M. Arago and myself, but more especially on my illus- 

 trious colleague, has appeared in the ' Quarterly Review/ The 

 ingenious and (as far as this controversy is concerned) not 

 very learned critic appears to be led away by the excess of 

 his zeal for Mr. Cavendish. I leave him in the hands of M. 

 Arago, who will observe with some wonder that he has been 

 accused and judged and condemned by a chemist so well 

 versed in that science, and so reflecting, as to announce the 

 astonishing novelty, that the exhibition of sulphur to sulphuric 

 acid reduces that acid and restores it to its primitive state 

 of sulphur ! The writer had probably read somewhere that 

 sulphuric acid is reduced to sulphurous by the process ; for he 

 is assuredly the first that had ever hit upon the acid's reduc- 

 tion by sulphur "to its primitive state/'* I have lying 

 before me fifteen pages of statements of chemical errors in 

 the thirty- four pages of the paper; and as these are the work 

 of a most experienced and learned and practical chemist, 

 whom I consulted on the above and other parts of the paper, 

 I have entire reliance on his report and opinion. I must 

 also add that he completely bears out, by the authority of his 

 concurring opinion, the statements (disputed by the critic) 

 which I had ventured to make respecting Dr. Black's dis- 

 coveries, with the single exception that he is not aware how 

 far I am justified in stating the greater specific gravity of 

 fixed air as known to him before Mr. Cavendish's experiments 



* The process of reducing phosphoric acid to its primitive phosphorus, had 

 just been stated, and the writer adds, " A similar succession of phenomena 

 are presented by sulphur, &c.;" and he enumerates sulphur as one of the 

 bodies which reduce the acid to its primitive state. 



