4. Sketch of the latest Improvements [Jan. 



other in an excess of it. Neither can I conceive with M. Dufay, 

 the Abbe Haliy, and some other French electricians, that negative 

 electricity consists in one fluid, and positive electricity in another, 

 which liave an attraction for each other, and neutralize each other 

 when they come in contact. But I can conceive negative and positive 

 electricity to he two attractions inherent in different bodies, which 

 make them unite with each other, and keep them united. But if 

 we adopt this view of the subject, we are not only embarrassed by 

 the difficulty of explaining many electrical phenomena, but we lose 

 the benefit of all the facts stated by Volta, and of most of those 

 advanced by Sir H. Davy in favour of his hypothesis. I myself, 

 therefore, though disposed to think favourably of the Davian hypo- 

 thesis of chemical affinity, consider it as very far from being suffi- 

 ciently established to constitute the basis of our researches and our 



arrangements 



This, however, has been done by Berzelius, who has bestowed 

 much attention on it, and is certainly far better acquainted with the 

 facts brouglit to light in support of it than I can pretend to be. His 

 view of the subject does not diffiir much from that of Sir H. Davy ; 

 but the additions which he has made when we come to compare 

 them with the present theory of electricity, or with any theory 

 hitherto proposed, are sufficiently puzzling. According to him the 

 acid or alkaline nature of a body depends upon the state of its 

 electricity. If it he permanently neoallve, it is of an acid nature ; 

 if it be permanently positive, it is alkaline. But when he adds that 

 a body may be positive with respect to one body, and negative with 

 respect to ' another ; though nothing is more easy than to reconcile 

 this with the common doctrine of chemical affinity, it would be 

 somewhat difficult to reconcile it with the theory of etectricity. 1 

 am far from saying tbat the thing is impossible; but in order to 

 attempt an explanation of it with success, it would be necessary to 

 make very sweeping changes in the electrical doctrines at present 

 admitted. 



Berzelius has' given a table of the chemical substances in the 

 order of the intensity of their electricities, beginning whh the one 

 attracted most strongly to the poshive pole, or the most intensely 

 negative substance ; and terminating with the body which is at- 

 tracted most strongly to the negative pole, and therefore is most 

 intensely positive. The negative intensity diminishes as we proceed 

 downwards in the table, and at last in the centre finally disappears. 

 Then the positive intensity begins ; at first very weak, but it gra- 

 dually increases as we go downwards, and becomes greatest at the 

 lower end of the table. Hence the affinity of the two substances 

 at the two extremes of the table is greatest of all ; and as we ad- 

 vance to the middle of the table, that affinity gradually diminishes, 

 and at last disappears. As I do not know the data from which 

 Berzelius constructed his table, I bave no means of judging of its 

 accuracy ; but I shall give the table in this place, as being well 

 entitled to the attention of the chemical reader. It is doubtless 



