132 
MR. C. F. YARLEY ON POLARIZATION OF 
short distance by placing one on each side of a double thickness of blotting-paper, and 
immersing the whole in diluted sulphuric acid, one volume of pure acid to four volumes 
of distilled water. By these means the resistance of the fluid between the plates was 
reduced to about part of an “ Ohm,” according to calculation from Becquekel’s data. 
These plates were connected as shown in fig. 4 (Plate II.). 
The current from two cells of Daniell’s battery was made to pass through the adjust- 
able resistance-coils It and It'. The united resistance of these coils, when the platinum 
bulbs were used, was made 1000 Ohms; when the platinum plates were used, it was 
made 100 Ohms. '* 
The two cells of Daniell’s battery had a resistance of about 12 Ohms, and by experi- 
ment their potential was found to be reduced from 344 to 317, or 8 per cent., by the 
resistance-coils 11 + It' connecting the poles of the battery when R + R^lOO Ohms, and 
therefore the potential of them was reduced to about two volts. 
By varying the resistance in II and B/, it is easy to get any desired subdivisions of the 
potential of the two volts, as Sir William Thomson and Sir C. Wheatstone have shown- 
The apparatus was sufficiently rapid and sensitive to read the discharge from the 
platinum bulbs and from condensers of 311 microfarads capacity for comparison there- 
with, when they were charged with a potential not greater than 0‘02 volt. 
Table II. shows the discharge from the platinum plates when charged by potentials 
varying from +2 of a volt up to T6 volt, also the discharge obtained from the con- 
densers of 311 microfarads capacity for comparison therewith. 
During each of the experiments in Table I. the sensitiveness of the galvanometer 
was maintained constant, and the results are directly comparable with those obtained 
from the condensers ; the same is the case in Table II. ; hut Table I. is not comparable 
with Table II., excepting by means of the last column. They were made at different 
dates, when the sensitiveness of the galvanometer was not the same. Thus it will 
be seen by reference to column 6 that, while the electrostatic capacity of the ordinary 
condensers remains constant ( i . e. the discharge varies directly as the “ potential ”), 
with the fluid plates this regularity is only observed while the charge is very low, not 
more than 0 - 08 volt (see Table I.). As the potential increases from yg- of a volt up- 
wards, the discharge from the platinum plates increases in a greater ratio, as will bp 
seen by column 6, which shows the deflection of the galvanometer divided by the 
“potential” to give the ratio; and it will be seen in Table I. that with potentials from 
•02 to - 08 the capacity was 1 as against 3'5 with a potential of about T6. 
An inference which the author thinks these experiments suggest is, that the water 
does not actually touch the platinum surface, and as the potential increases the water is 
attracted nearer to the electrified plate, thereby augmenting its electrostatic capacity 
as the distance between the platinum and the water is diminished by the electric 
attraction. 
When, however, the repulsion between the platinum plate and the water is overcome 
by the electric attraction, then conduction of the current would seem to take place, 
