SIR B. C. BRODIE ON THE ACTION OF ELECTRICITY ON GASES. 
449 
In another similar experiment the gas was analyzed in the first instance, after having 
been submitted to the electric action and passed through the solution of iodide of 
potassium, and was found by detonation with hydrogen, in two determinations respect- 
ively, to contain 99'5 and 99 - 0 per cent, of oxygen. The action of the coil was stopped, 
the passage of the current of oxygen continued for an hour, and the gas was again 
collected and analyzed ; it was found to contain 99 per cent, of oxygen. 
The experiments of which the results are given in the Table below were instituted 
with the view of effecting a comparison between the amount of oxygen corresponding to 
the “ titre ” of the gas and the increment of weight of the solution of iodide of potas- 
sium through which the electrized gas was passed. 
The general arrangements were the same as in the experiments last described. A 
current of pure and dry oxygen was passed direct from the generator through the 
induction-tube, where it was submitted to the electric action ; thence it was passed 
through a tube containing anhydrous phosphoric acid into the bulb containing the solu- 
tion of iodide of potassium ; to this a second tube, containing anhydrous phosphoric 
acid, was attached, which was weighed, together with the bulb containing the solution 
of iodide, before and after the experiment, the exit of the gas being through a fine 
capillary tube. At the commencement of the experiment a current of oxygen was 
passed through the apparatus until the weight of the bulb of iodide of potassium and 
the desiccating tube attached to it became constant ; they were similarly weighed after 
the experiment, the difference of weight in the two cases being the increment of weight 
due to the passage of the electrized gas. 
In column I. this increment of weight is given, W ; in column II. the corresponding 
“ titre” (that is to say, the weight of oxygen corresponding to the iodine found), T ; in 
column III. the difference of these two, W — T ; in column IV. the increment of weight 
W 
corresponding to 100 parts of oxygen as estimated by titration, that is lOOx-rp. 
I. 
w. 
II. 
T. 
III. 
W-T. 
IV. 
w 
100 x". 
grm. 
grm. 
grm. 
•0719 
•0689 
•003 
104-3 
•1932 
•1865 
•0067 
103-5 
•1602 
•1548 
•0054 
103*4 
•3338 
•3245 
•01 1 
103-2 
•3939 
•3836 
•0103 
102- 7 
103- 4 = Mean. 
The strength of the solution of iodide of potassium was intentionally varied in the 
last two experiments — the last experiment being made with a very weak solution of 
iodide of potassium containing 2 grammes of iodide in 25 cub. centims. of water, the 
preceding experiment with a relatively very strong solution. It hence appears that for 
every 100 parts of oxygen shown by the “titre” of the solution 103 - 4 parts of matter 
