16 



Transactions^. 



The aperture Q in B received the pipe R, through which COo under 

 pressure was forced into the cell. This pipe terminated in the flange S, 

 which could by means of the nut W be forced home on a lead washer at T. 

 The gas passed through a small hole in the washer, then through the passage 

 U into the conductivity-vessel. 



j-lalj-.secdon 



Cell 



riiift of conne^oMi:. 



The details described made the vessel in practice perfectly gastight. 

 The inside of the vessel was gold-plated, and an inner vessel of special Jena 

 glass, manufactured for conductivity purposes, was placed within the 

 outer plated one, which it fitted closely. As a further precaution, the part 

 of the head near the shoulder J which was exposed above the solution was 

 coated with insoluble enamel. (As a matter of fact, this was needless, as it 

 was found in working that no water condensed on the head and upper part 

 of the electrodes.) 



Thus only the best Jena glass (beside the platinum electrodes) was in 

 contact with the solution, and this glass was found to impart a definite 

 but very small conductivity, which could be, and was, allowed for through- 

 out the work. 



Regulation of Temperature. 



During the experiments conducted at 18° the electrolytic cell was im- 

 mersed in a thermostat, fitted with a large toluol-mercury thermo-regu- 

 lator and a centrifugal stirrer worked by a hot-air engine. This gave very 

 satisfactory results, the temperature never varying by 0-05° on either side 

 of 18°. For experiments at 0° the conductivity-vessel was immersed in 

 crushed ice, which was fiecjuently r<'iiewed. Probably the temperatui'c of 



