40 Messrs. Wright and Thompson on the Determination of 
was close to 2HC1, 50H 2 O and 2HC1, 100 H 2 in the first 
and second experiments respectively, and the sulphuric-acid 
H 2 S0 4 , 50 H 2 and H 2 S0 4 , 100 H 2 O in the third and fourth 
experiments respectively. The zinc plates were amalgamated, 
the cadmium ones not. 
142. The experiments described in Parts IV., V., and VI. 
indicate that the amount of diminution brought about in the 
E.M.F. of an electromotor (either a simple cell, or one after 
Daniell's construction) by an increase in the current-density 
may readily greatly exceed any possible effect due to the accu- 
mulation round the two plates of fluids of widely different 
molecular strength, and, further, that, as a general rule, the 
effect of diminishing the area of the plate on which the metal 
is deposited is considerably greater than that of a similar 
diminution in the area of the other plate, although this is not 
invariably the case. It is hence evident that the chief source 
of nonadjuvancy especially lies in the incomplete manifesta- 
tion as electricity of the energy due, after the elimination by 
the action of the current of the deposited metal (or body 
equivalent thereto) in the nascent form, to the subsequent 
transformation thereof into the permanent form. Clearly the 
same kind of thing must be equally true for the other products 
of electro^sis evolved at the other electrode. Hence the reason 
why a less amount of non-adjuvancy is brought about at this 
side is presumably the greater amount of attraction exercised 
by the material of the electrode for the nascent product ("sul- 
phion" of Daniell in the case of cells containing sulphates) here 
evolved, owing to their opposite chemical characters, than is 
observable at the other electrode. Admitting this to be so, it 
should result that the more oxidizable the metal dissolved {%. e. 
the greater the heat of formation of the compound produced 
by its solution), the less will be the amount of nonadjuvancy 
due to the incomplete conversion into electricity at this plate 
of the energy due to transformation of nascent into final 
products. The results of the experiments hitherto described, 
however, being complicated by the formation of solutions of 
different strengths around the two plates, are not sufficiently 
precise to show that, under given conditions, a zinc plate, for 
example, causes less nonadjuvancy than a cadmium one, and 
so on. Accordingly the following experiments on the point 
were made, the result of which is to show indisputably that 
the more oxidizable the metal the less the nonadjuvancy. 
An electrolytic cell was constructed, consisting of a wide 
glass tube closed by india-rubber bungs through which passed 
wires terminating interiorly in the plates to be experimented 
with, the opposed plate-surfaces being perpendicular to the 
