1814.] On the Cause of Cliemical Proportions. 53 



volume, because this relation between them is constant, not only 

 with respect to all the metals, but likewise with respect to carl)oa 

 and hydrogen. As 100 parts of lead combine with 7'7 parts of 

 oxvgen and with 15'42 parts of sulphur, the volume of the first 

 ought to be to that of the last as 77 : 154-2, or 100 : 201. But, 

 on the other hand, if we take for the base of our calculation an 

 analysis of sulphate of lead, which I made by neutralizing a deter- 

 minate quantity of oxide of lead with sulphuric acid (Ann. de Chim. 

 Aug. 1811, p. 121), we find the volume of sulphur to weigh as 

 much as 210. On the other hand, if we oxidate lead iiy means of 

 nitric acid, and ()Our sulphuric acid into the solution, we obtain, 

 after evaporation and ignition of the mass, a quantity of sulphate 

 of lead (Ann. de Chim. Oct. 1811, p. 11), which, taken as the 

 base of our calculation, gives us the volume of sulphur as light as 

 200. There is a want of precision in some of tliese experiments, 

 which makes the weight of a volume of sulphur uncertain between 

 200 and 210. 



VVc know that sulphur combines with oxymuriatie gas in two 

 proportions, constituting two muriates with different bases. In one 

 of these muriates the sul])hur is combined with i as much oxygen 

 as in sulphurous acid, and in the other with i as much. Now is it 

 not probable that these degrees of oxidation are S + O, S + 2 O, 

 S + 4 O, S + t> O ? In which case the acid is composed of 1 

 volume of sulphur and 6' volumes of oxygen. The following cir- 

 cumstances strengthen this opinion: — 1. Most acids in /c contain (l 

 volumes of oxvgen, while the acids in ons contain 4 volumes. The 

 only decided exceptions are tlie phosphoilc and muriatic acids. In 

 the neutral chromates and arseniatcs the acid contains three times 

 as much oxygen as the base, though these acids contain evidently 

 G volumes of oxygen. 2. If we suppose sulphuric acid to be S + 

 3 O, the persulisulphate of copj)er {suli.^7il/j/ius ci/prhus) is 1^ Cu 



O + S O ; but if we suppose this acid to be S + (> O, the salt in 



question will he 3 Cu O + S O; and the anomaly of the half 

 volume would be destroyed. Tiicse observations give some proba- 

 bility to the notion ; vet the constant relation between the weight 

 of sulphur and oxygen which unite most readily with any metal, 

 added to the circumstance that no compound equivalent to S + 

 3 O (supposing sulplunic acid S + (j O) has been yet found, 

 though sucli a compound ougiit not only to exist, but to combine in 

 preference with bases — these circumstances seem suftkiently to 

 refute the notion, and to |)rovc that the four dci^rees of oxidation of 

 sulphur ought to be expressed thus: 2 S + O, .S + O, S + 2 O, 

 S -f 3 O. The argimient drawn from the persubsulphate of copper 

 loses much of its value when v.e compare it u'itli the suhirsfii'tntcSf 

 in which h.df a volume of the base is added tothe neutral arseniates, 

 and in whieli no cx[)lanation will make this half disappear. 



2. Min'iiil'inini, 7ii7/ria/ic rml'ile (.\1). — Though we are tmable 

 to obtain this body in a sepiirau; -.tate, oi to ctimbine ii with any 



