452 On the Cause of Chemical Proportions. [Dkc. 



bodies, we find that those which are distinguished by a strong 

 affinity between their constituent parts, and by the force of their 

 chemical affinity for other bodies, contain evidently more than 

 one volume of one of their elements. This is the case with 

 water, carbonic acid, nitrous gas, &c, and, with very few 

 exceptions, it is always the electro-negative element the volume 

 of which is multiplied. On the other hand, in bodies composed 

 distinctly of equal volumes, such as the nitric suboxide (azote), 

 and carbonic suboxide (carbonic oxide), we find all the negative 

 properties which characterize the suboxides. This leads me to 

 suppose that all- tlve suboxides are composed of equal volumes of 

 their elements. It follows from these observations that the most 

 part of the salifiable oxides and acids ought to be composed of 

 more than one volume of oxygen for each volume of radicle. 



Experiment seems to prove that if a combustible radicle com- 

 bine in preference with 2 or 3 volumes of oxygen, it combines 

 likewise in preference with 2 or 3 volumes of sulphur. If a 

 salifiable oxide be composed of 1 volume of radicle and 2 or 3 

 volumes of oxygen; and if we neutralize this oxide by any acid 

 whatever, it is to be supposed that the neutral combination 

 which results ought to contain for 1 volume of the radicle of the 

 oxide as many volumes of the radicle of the acid as the oxide 

 contains volumes of oxygen; and, consequently, that the number 

 of times which the acid contains the oxygen of the oxide will be 

 the number of volumes of oxygen combined with 1 volume of 

 the radicle of the acid : for example, we consider sulphuric acid 

 as composed of 1 volume of radicle and 3 volumes of oxygen ; 

 because it is very probable that the quantity of sulphur and of 

 oxygen capable of combining at an elevated temperature with a 

 given portion of lead constitute equal volumes. But if we want 

 to know by another method how many volumes of oxygen exist 

 in sulphuric acid, we have only to examine the composition of 

 some sulphate ; for example, sulphate of iron (sulphas j'errosus). 

 The black oxide of iron contains 1 volume of metal and 2 

 volumes of oxygen. It follows, from what has been said, that 

 the black oxide of iron ought to be neutralized by a quantity of 

 acid containing 2 volumes of sulphur for every volume of iron : 

 so that the number of volumes of the sulphur of the acid and of 

 the oxygen of the base shall be equal. But the acid contains 

 three times as much oxygen as the base ; consequently, it is 

 composed of 3 volumes of oxygen and 1 volume of sulphur. If, 

 instead of the sulphate of iron, we were to make choice of the 

 persulphate of iron (sulphas ferricus), it is evident that in such a 

 case the iron is combined with 3 volumes of sulphur, so that the 

 result is just the same. 



This observation would be sufficient to determine the volume 

 of a substance whose oxide possesses the characters of an acid, or 



