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190 Faraday as a Discoverer. 
the others. The terms Anion and Cation, which he applied : 
the constituents of the decomposed electrolyte, and the term io, 
which included both anions and cations, are still less frequently 
employed. 
Faraday now passes from terminology to research; he sees the 
necessity of quantitive determinations, and seeks to supply him- 
self with a measure of voltaic electricity. This he finds in the 
quantity of water decomposed by the current. He tests thi 
measure in all possible ways, to assure himself that no error caa 
arise from its employment. He places in the course of one and 
the same current, a series of célls with electrodes of different: 
sizes, some of them plates of platinum, others merely platinum 
wires, and collects the gas liberated on each distinct pair of elee- 
trodes. He finds the quantity of gas to be the same forall 
: _ Thus he concludes that when the same quantity of el 
does not interfere with this law. Sending the same ¢ vd 
through a series of cells containing mixtures of sulphure 
tion of acid to water might vary, the same amount of ue 
collected in all the cells. A crowd of facts of this ¢ of 
the electrodes, not upon the intensity of the current, a 
the strength of the solution, but solely upon the que 
electricity which passes through the cell. The quantity nical 
tricity, he concludes, is proportional to the amount of 
action this law Faraday based the construction 
celebrated voltameter, or measurer of voltaic Petraes - 
De la Rive, and others had shown, there are also ‘cate the 
in two 
rfere with and comp. 
pure action of the current. These actions may 0 ectrodé 
with 
