a 
B.—CHEMISTRY. 37 
they were communicated to the Royal Society with the title ‘On a New 
Law of Electric Conduction.’ 
Faraday then turned his attention to the mechanism of conduction in 
aliquid. On May 2 he passes a strong current through a saturated solution 
of sodium sulphate and examines it with polarized light both across and 
along the direction of the current to see if he can detect signs of arrange- 
ment of the molecules, but without result. On May 20 he determines 
the transfer of sulphuric acid during electrolysis by measuring the changes 
in concentration in two vessels connected by moist asbestos, and on 
May 27 he shows that the transfer of sulphuric acid differs from that of 
sodium sulphate of equivalent concentration, ‘very evident therefore 
that the transfer is dependant on the mutual action of the particles.’ 
He summed up his views in a paper to the Royal Society on June 18, the 
main conclusion being ‘that electro-chemical decomposition does not 
depend on the simultaneous action of two metallic poles,’ and the effects 
of it ‘ are due to a modification, by the electric current, of the chemical 
affinity of the particles through or by which that current is passing, giving 
them the power of acting more forcibly in one direction than in another, 
and consequently making them travel by a series of successive decom- 
positions and recompositions in opposite directions, and finally causing 
their expulsion or exclusion at the boundaries of the body under decom- 
position.’ 
On May 16 no experiments were recorded in the note-book but among 
the ideas he jotted down was—‘Is the law this (above a certain in- 
tensity, i.e. the one required for decomposition to take place at all) that 
whatever the size of plates or number intervening or constant section of 
decomposing matter, or variable section, or variable strength, or number 
of series in the battery: that . . . equal currents of electricity measured 
by the galvanometer evolve equal volumes of gas or effect equal chemical 
action in a constant medium.’ A week later he writes down his plans for 
testing the law—‘ By putting cups and expts. in succession and sending 
the same electrical current through both or all am sure that each is sub- 
mitted to an equal force. Can try well this way whether the same quantity 
of different intensity does the same chemical work using same dilute 
sulphuric acid but different sized poles, and collecting gas, and that will 
tell—some poles mere wires, others large plates.’ Three months elapsed 
before he actually carried out the experiment: on August 27 he wrote, 
‘Pursue the investigation, whether the same quantity of electricity 
always produces an equivalent of chemical decomposition. .. .’ On 
August 30 he found as he expected that the same amount of current 
liberated the same volume of gas irrespective of the concentration of the 
acid, the size of the electrodes or the intensity’ of the current. He 
obtained the same results with solutions of various salts, and his comment 
was, ‘ Strange that with such different substances the same quantity of 
water should be decomposed by the same current.’ These experiments 
were continued in September and Faraday was constantly puzzling over 
the effect of various substances in increasing the conducting power of 
1 By intensity Faraday here means current density; later he uses it in the sense 
of electromotive force. 
