Electric Discharge in rarefied Hydrogen and Oxygen. 311 



(X being 750) for the pressure 1*85 mm. ; whereas with the 

 current -00275 A/v'AQ would have been 6*4 (X about 770). 



AnotJi er Experiment. 



At the beginning of this paper I referred to another 

 apparatus. This was designed with the view of confirming 

 my conclusion that the greatest intensity of chemical activity 

 existed in the cathode fall. A section of it is shown in fig. 4 

 which is drawn fairly to scale. 



Fis. 4. 



P-f 



*-Q 



It was made of glass tubing from the side of which two 

 bulbs, roughly spherical in form, were blown. Pieces of 

 platinum carrying aluminium electrodes were fused into the 

 ends P, Q of the tubing. The vertical tubes E, S permitted 

 the introduction of phosphorus pentoxide (shown by the 

 shaded areas) into the bulbs without soiling the electrodes, 

 after which R and S were closed at the top. The distance 

 between the electrodes was 11*6 cms. and the diameter of 

 each was 1*4 cm. The diameter of the bulbs was 4 cms. and 

 their orifice roughly a circle of 3 cms. diameter. Hydrogen 

 and oxygen entered the apparatus when evacuated of air bv 

 the side tube T. 



The terminals P, Q of the electrodes were connected to a 

 battery of 1200 volts and the pressure was sufficiently reduced 

 to allow a current of about '0026 ampere to pass between 

 them. The current was started by means of an induction- 

 coil and was maintained by the battery for about half an hour. 

 As the gas disappeared through chemical action it was 

 replaced by fresh gas, the pressure varying between about 

 3 rams, and 7 mms., in such a way as to keep the current 

 about the same as its initial value and continuous. The 



