88 On some new. Electrochemical Researches 



bases would be inversely as the quantity of oxygen that 

 they contain ; and supposing the power of attraction to be 

 measured by the quantity of basis which an acid dissolve?, 

 it would be easy to infer the quantities of oxygen and me- 

 tallic matter from the quantities of acid and of basis in a 

 neutral salt. On this idea 1 had early in 1808 concluded 

 that barytes must contain least oxygen of all the earths, 

 and that the order as to the quantity of inflammable matter 

 must be strontites, potash, soda, lime, and so on ; and that 

 silex must contain the largest quantity of oxygen of all. 



If the most accurate analyses be taken, barytes may be 

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

 tites 86f, lime 73 5*, magnesia 66 J, 



The same proportion would follow from an application 

 of Mr. Dalton's ingenious supposition§, that the proportion 

 of oxygen 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 

 oxygen, and one of acid. 



We are in possession of no accurate experiments on the 

 quantity of acids required to dissolve alumine, glucine, 

 and silex; but according to Richter's estimation of the 

 composition || of phosphate of alumine, alumine would 

 appear to contain about 56 per cent, of metallic matter, 



* Mr. James Thompson, Nicholson's Journal, 1809, p. 175, and Berthier. 



f Mr> Clayfield. Thomson's Chemistry, vol. ii. p.'626, 629. 



$ Murray's Chemistry, vol. iii. p. 616. 



§ The principle that I have stated of the afhnity of an acid for a salifia- 

 ble basis being inversely as the quantity of oxygen contained by the basis, 

 though gained from the comparison of the electrical relations of the earths, 

 with their chemical affinities, in its numerical applications, must be consi- 

 dered merely 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 alkalies and alkaline earths; which, in the case of the 

 alkalies, were not very remote from what I had ascertained by direct ex- 

 periments. M. Gav Lussac'3 principle, that the quantity of acid' in metallic 

 salts is directly as the quantity of oxygen, might (as far as it is correct) be 

 inferred from Mr.jDalton's law, though thia ingenious chemist states that he 

 was led to it by different considerations. According to Mr. Dalton, there 

 is a proportion of oxygen, the same in all protoxides, and there^ is a pro- 

 portion of acid, the same in all neutral salts; and new proportions of oxy- 

 gen and of acid are always multiples of these proportions. So that if 3 

 protoxide in becoming a deutoxide takes up more acid, it will be at least 

 double the quantity, and in these cases the oxygen will be strictly as the 

 acid. Mr. Dalton s law even provides for ea;>es to which M. 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 oxysulphat 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 

 8uper-tartrite of potash there is only a single quantity of oxygen, and a 

 double quantity of acid. Whether Mr. Dalton's law will apply to all cases t 

 ~i& a question which I ^hall not in this place attempt to discuss. 



I] Thomson's Chemistry, vol. ii. p. 531. JVJ, Ber* 



