On the Nature of Alkalis and Eartks. Id 



what Lavoisier suspected, that the alkalis and earths are 

 metallic oxides." 



This " only verifying" seems to him a matter of very 

 little importance, and the guess much more curious than 

 the discovery, Reasoning in this way, it may be said, that 

 Newton only verified what Seneca suspected, and that Co- 

 lumbus had only rediscovered Plato's Atalantis. 



From such a writer accuracy is not to be expected. His 

 first assertion is incorrect. Lavoisier never supposed the 

 fixed alkalis to be metallic oxides. In his time there were 

 no analogies which led to such an opinion. This sagacious 

 philosopher, on the contrary, has stated the idea that they 

 may contain azote ; which O. may see in the very book he. 

 quotes, Kerr's Translation of Lavoisier's Elements, second 

 edition, page 213. 



Before Lavoisier, even as early as Van Helmont jun. and 

 Beccher, it was conceived that metals were capable of being 

 produced from earths. Bergman, in later times, but before 

 Lavoisier, published the opinion with respect to barytes ; 

 and Baron, with respect to alumine : but this kind of read- 

 ing cannot be familiar to O., a person who seems to believe 

 in the results of the experiments of Toudi and Ruprecht, on 

 the metallization of the earths, and merely says, that their 

 accuracy was called in question by Klaproth and Tihawski; 

 whereas the fact is, that the metallic substances obtained by 

 Toudi and Ruprecht were proved by Tihawski and by Klap- 

 roth to be phosphurets of iron : and the question was laid 

 at rest by the elaborate researches of Savaresi, who showed 

 that they could not be obtained except in cases when mate- 

 rials which furnished phosphuret of iron were present. See 

 Annates de Cliimie, tome ix. p. 275, and tome x. p. 118. 



Mr. Kerr, in his Translation of Lavoisier's Elements, se- 

 cond edition, has reasoned upon the experiments of Toudi 

 and Ruprecht as if they were correct ; stating that if mag- 

 nesia be a metallic oxide, then soda, being a modification of 

 magnesia, " according to some experiments published in 

 the Transactions of the Turin Academy," must be also a 

 metallic substance. He might have gone further, and said, 

 that as M. Guy ton de Morveau has proved potash to be 



M 2 partly 



