THE NEW CHEMISTRY. 397 



acid. But oxygen and sulphur are both electro-negative elements. 

 Berzelius supposed that sulphur contained a large quantity of both 

 electricities, the negative predominating. When this element com- 

 bined with oxygen, the positive electricity of the sulphur was Sup- 

 posed to be neutralized by the negative electricity of the oxygen, so 

 that the negative electricity of the sulphur was concentrated or ren- 

 dered more apparent. The affinity between oxygen and silver is less 

 than that between sulphur and oxygen, because, said Berzelius, silver 

 contains mainly positive electricity, but a smaller quantity than is 

 found in sulphur. The product of the union of oxygen and sulphur, 

 i. e., of oxygen with an electro-negative body, belongs to the class of 

 acid oxides ; the product of the union of oxygen and silver, i. e., of 

 oxygen with an electro-positive element, belongs to the class of basic 

 oxides. 



If this view of the composition of oxides were granted and a most 

 ingenious and plausible theory it was why should we not proceed a 

 step further and say that an acid acts so readily upon a base, because, 

 in the first, negative electricity predominates, while the prevailing- 

 electricity in the latter compound is positive ? 



And, in further support of this view, could it not be experimentally 

 demonstrated that when a salt, such as sulphate of sodium, is decom- 

 posed by the electric current, the soda goes to the negative pole, while 

 the sulphuric acid appears at the positive pole ? The experiment of 

 decomposing a solution of sulphate of sodium was frequently per- 

 formed, and the fact that, if the solution were colored with litmus, 

 that portion around the negative pole retained its blue color, while 

 that around the positive pole became red, was regarded as conclusive 

 evidence of the dualistic structure of the salt operated upon. 



But, about the year 1834, Dumas told the chemical world that 

 chlorine was capable of " laying hold of the hydrogen of certain bodies 

 and replacing it atom for atom." If this be so, said Berzelius, the 

 compound formed must differ essentially from that from which it is 

 derived. Chlorine is an electro-negative element, and, if it enter into 

 a compound in place of the electro-positive hydrogen, the original 

 compound and the new compound can present no points of analogy. 

 The theory seemed correct, but unfortunately the chlorinated body did 

 present very marked analogies with that from which it had been pro- 

 duced. Berzelius attempted many exj)lanations, invented many new 

 compound groups of atoms, which should be supposed to enter into 

 the composition of the new bodies discovered by Dumas ; but his 

 electro-chemical theory was doomed. It was gradually abandoned by 

 most chemists, and the substitutionists carried the day. 



Berzelius had largely availed himself of certain facts, which showed 

 that, in series of reactions, it was sometimes possible for a group of 

 dissimilar atoms to remain intact, to move about, so to speak, from 

 one compound to another without falling to pieces. Reasoning on 



