ON THE METALS OP EARTHS. JQg 



the quantity of inflammable matter, must be strontites, 

 potash, soda, lime, and so on ; and that silex must contain 

 the largest quantity ofoxigen of all. 



If the most accurate analyses be taken, barytes may be Inferences. 

 conceived to contain about 90*5* of metal per cent, strontites 

 86t, lime 73'5*, magnesia, GG^. 



The same proportions would follow from an application of Composition of 

 Mr. Dalton's ingenious supposition§, that the proportion Seu^'raurUs!'^ 

 ofoxigen is the same in all protoxides ; and that the quan- 

 tity of acid is the same in all neutral salts, i. e. that every 

 neutral salt is composed of one particle of metal, one of 

 oxigen, and one of acid. 



* Mf. James Thompson, Nicholson's Journal, vol. xxiii, p. 175, and 

 Berthler. 



t Mr. Clayfield, Thompson's Chemistry, vol, ii. p, 626, G29. 



J Murray's Chemistry, vol ill, p. 616, 



(j The principle, that 1 have stated, of the affinity of an acid for a 

 salifiable basis bfiing inversely as the quantity of oxigen contained by the 

 basis, though {gained from the comparison of the electrical relations of 

 the earths with (heir chemical affinities, in its Mumerical applications, 

 must be considered meiely as a consequence of Mr. Dalton's law of 

 general proportions. Mr. Dalton had indeed, in the spring of 1808, 

 communicated to me a series of proportions for the alkalis and alkaline 

 earths; vrhich, in the case of the alkalis, were not very lemote from 

 what I had ascertained by direct experiments. Mr. Gay- Lussac's prin- 

 ciple, that the quantity of acid in metallic saits is directly as the quantity 

 of oxigen, might (as far as it is correct) be inferred from Mr. Dalton's 

 law; though this ingenious chemist states, that he was led to it by dif- 

 ferent considerations. According to Mr. Dalton, there is a proportion 

 of oxigen, the same in all protoxides ; and there is a proportion of acid, 

 the same in all neutral salts; and new proportions of oxigen and of acid 

 are always multiples of these proportions. So that, if a protoxide, in 

 becoming a deutoxide, lakes up more acid, it will be at least double the 

 quantity; and in these cases the oxigen will be strictly as the acid. Mr. 

 Dalton's law even provides for cases, to which Mr. Gay-Lussac's will not 

 apply ; a deutoxide may combine with a single quantity of acid, or a 

 protoxide with a double quantity. Thus in the insoluble oxisulphat of 

 iron perfectly formed, (as some experiments, which I have lately made, 

 seem to show,) there is probably only a single proportion of acid ; and 

 in the supertartrite of potash there is only a single quantity of oxigen, 

 and a double quantity of acid. Whether Mr. Dalton's law will apply to 

 all cases, is a question which 1 shall not in this place attempt to 

 iliscus^. 



We 



