1888.] current on saturated solutions. 225 
fluid, it was scarcely possible however fast the commutator was 
run to prevent some trace of bubbles forming on one or both of 
the electrodes. In no case of course was the electrolysis allowed 
to take place to any extent, but there seemed no sensible difference 
between results obtained on occasions on which it could not be 
seen and other occasions on which it could. 
The electrodes were of platinized platinum foil and were 
several times subsequently replatinized, and the effect of this in 
getting rid of electrolysis was very marked. 
The solution was contained in a glass jar, which was usually 
placed in a vessel containing water so as to check the heating 
effect of the current. The electrodes were supported so as nearly 
to reach the bottom of the glass jar, which was convex upwards. 
Fragments of the salt were always placed in the jar so as to lie 
between the electrodes, and an additional supply of the salt was 
suspended near the fluid surface on a flat wooden spoon in a 
position towards one side of the jar but still right in the path of 
the current. Samples of the fluid were taken out by means of a 
10c.c. pipette, and in removing them care was taken to hold the 
end of the pipette in the path of the current midway between 
the electrodes, and to keep it well clear of the wooden spoon and 
also of the bottom of the jar. The samples being taken at a 
distance of an inch or so from either electrode, the effects of any 
electrolysis were presumably in great measure done away with. 
The general order of carrying out an experiment was as follows. 
A cover, used to keep out dust, was taken off the glass jar, the 
electrodes inserted, and the solution well stirred. It was then 
seen that a fair number of undissolved crystals, always kept in 
the solution, were between the electrodes, and the spoon with its 
load of salt was put in its place. After a lapse of several hours a 
sample of the solution was taken and the current was then started. 
After an interval of from 40 to 120 minutes a second sample was 
taken and the current was then stopped. Finally after another 
interval of from 20 to 60 minutes a third sample was taken. On 
taking each sample the time and the temperature of the solution 
were noted. 
Great care was exercised in filling the pipette, and it was 
always emptied in the same way and washed out a certain number 
of times into a small flask which was then corked and labelled. 
The flask was subsequently washed out repeatedly into a half 
litre flask which was then filled up to the mark. From the half 
litre flask 10 or 20c.c. were removed by the pipette, which was 
washed out into a small beaker and the contents titrated with 
argentic nitrate. As a rule distilled water was used in all the 
operations, but in some of the experiments on calcium chloride a 
large vessel was filled with undistilled water and its contents used 
