452 NOTICES OF THE MEETINGS [June 2, 
became excited. Thus, a particle of sulphur became negative when 
placed in contact with a particle of copper, which last was simul- 
taneously rendered positive: the application of heat intensified the 
charge, until at a certain point, the tension of the two electrici- 
ties became so high, that they suddenly re-combined, carrying with 
them the molecules of copper and sulphur, which were thus 
intimately mingled, whilst evolution of heat and light resulted 
from the combination of the two electricities. Ampére and Ber- 
zelius subsequently attempted to remove some of the difficulties, 
which were encountered in endeavouring to make Davy’s theory 
embrace all chemical phenomena. Ampére considered each element 
to be permanently endowed with a definite amount of one or the 
other electricity, being thus invariably either electro-positive or 
electro-negative to an extent dependent upon the intensity of the 
charge. Such a naturally charged molecule Ampére imagined to 
attract around it an atmosphere of the opposite electricity of cor- 
responding intensity, and that when two molecules oppositely 
charged were brought in contact, their atmospheres of electricity 
united, giving rise to the heat and light of chemical combination, 
whilst the original charge retained the attracting molecules in per- 
manent union. Although this theory elucidated some points which 
Davy’s view left unexplained, yet it would not be difficult to start 
several very serious objections to it: the attempted removal of these 
gave rise to the electro-chemical theory of Berzelius, who sup- 
posed that each element contained the two electricities, but that 
the one was more powerfully developed than the other, as in 
the case of a magnet in which one pole, by being divided, was 
apparently weaker than the other. In chemical combination, Berze- 
lius imagined, that one of the electricities of each element was 
discharged, producing the heat and light of chemical action, whilst 
the other was retained and served to hold the elements in combi- 
nation. 
But these attempts of Ampére and Berzelius to improve the 
theory of Davy succeeded perhaps less in perfecting our views of 
electro-chemical phenomena, than in demonstrating the necessity 
for much further research, before these phenomena could be satis- 
factorily interpreted ; for these theories, in which different degrees 
of affinity were explained by differences in the degree of elec- 
trical excitement, have been proved radically defective by the 
remarkable discovery of Professor Faraday, that compounds, whose 
elements were united by the most dissimilar degrees of affinity, 
required equal quantities of electric force for their decomposition. 
Such defects in the attempts to account for chemical phenomena 
by electrical agency led Dumas and other chemists to reject 
altogether the idea of electro-chemical combination. Dumas re- 
garded a chemical compound as a group of molecules connected by 
a single force in a manner analogous to a planetary system, and the 
chemical character of a compound as dependant upon the position 
