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J. W. Langley—Chemical Affinity. 365 - 
action of their integral parts. In the mixture of liquid sub- 
stances (neutral) those combinations which ought to act with a 
force of cohesion capable of separating them ought to be 
formed and separated in fact.” 
The position assumed by Berthollet was, of course, finally 
“overthrown by the improvements in methods of analysis on the 
one hand, and by the Daltonian theory of atoms on the other; 
but it is a noteworthy fact that it is only as a complete and uni- 
versal explanation of chemical action that Berthollet’s theory 
fails. In many respects his position still holds good and his 
Other on masses of matter.” His contemporaries and suc- 
cessors, Oerstedt, Grotthus, Ampére, Becquerel, Berzelius and 
Faraday amplified and extended the electrochemical theory. 
Grotthus contributed his well-known hypothesis of liquid 
polarization. Ampére considered that each atom is surrounded 
bya special atmosphere of electricity, positive or negative, and 
that combination of atoms occurs the neutralization of the 
Opposing atmospheres. Berzelius held that the atoms have 
oles. He says," “Affinity is only the effect of the electric 
polarity of the particles; electricity is the primary cause of 
their chemical action; it is the source of the light and heat dis- 
engaged during combination ;” and ‘finally Faraday’s immense 
contribution to electro-chemistry is too well known to need 
any farther mention her 
