On the Chemical Constitution of Acich, Alkalis, &c. 91 



opposition to the law of definite proportions in chemical com- 

 binations ; for, according to that law, the higher proportion of 

 an element in combination with another is a simple multiple of 

 the lower proportion in which it combines with the same bodv. 

 And hence, since in the first combination of sulphur with oxygen, 

 100 of the former are combined with 100 of the latter; in the 

 second, 100 ought to be combined with 200, while the combina- 

 tion is that of 100 to 150. And in the atomic hypothesis, this 

 involves the absurdity of supposing, that while, in the first com- 

 pound, the combination, in conformity to the common rule, is 

 that of one atom of sulphur with one atom of oxygen ; in the se- 

 cond, it is that of an atom of sulphur with an atom and a half of 

 oxygen. To obviate this, it is supposed that a combination of sul- 

 phur with a lower proportion of oxygen exists, — an oxide com- 

 posed of 100 of sulphur with 50 of oxygen. The ratio will then 

 be that of 1,2, S of oxygen in the three compounds to one of 

 sulphur. And in the atomic system, the first will l)e held to be 

 that of an atom of sulphur with an atom of oxygen; the second, 

 that of an atom with two atoms; and the third, tliat of one with 

 three. To this, however, it may be objected, th-it no sucli oxide 

 of sulphur can be obtained, though if it were a possible combina- 

 tion, it ought, from the law of attraction, that the first proportion 

 of an element is retained in union with the greatest force, to be 

 the one most permanent and most easily obtained. 



Whether this objection be just or iiit, the difficulty can be 

 solved without any iiypothesis, on the view that the elements of 

 the supposed water exist in the compo^^irion oftb.eacid; for the 

 quantity of oxygen in this water is just 50; of course, the entire 

 (]uantitv is tlie regular proportion 200. And the composition is 

 100 of sulphur, 200 of oxygen, and 67 of hydrogen. 



This result favours the conclusion, that the relation of the oxy- 

 gen in common sulphuric acid is entirely that of this element to 

 sulphur ; that it is therefore in immediate combination with the 

 radical ; and hence, that water does not exist in the constitution 

 of the acid. And even if the existence of an oxide of sulphur and 

 of what is called real sulphinic acid were admitted, tlie combi- 

 nations would be strictly conformable to the law of proportions, 

 being those of one of sulphur to 1, 2, 3, and 4 of oxygen. 



The proportion of hydrogen is also determined by its relation 

 to the sul|)hur; for its (juantitv is that in whicli they comi)ine, G"7 

 of hydrogen with 100 of sulphur coubtituting the compositioji 

 of sulphuretted hydrogen. 



It thus appears that the proportions of both elements are de- 

 terniiued by their relation to the sulphur as the radical of the acid, 

 and are those which the (juantity of sulphur would separately 

 require. This, so far as theory can discover, is not a neces- 

 sary 



