1893.] 



The Electrolysis of Steam. 



105 



water the hydrogen always comes off at the negative, the oxygen at 

 the positive, electrode, in the case of steam the hydrogen and 

 oxygen come off sometime at one terminal, sometimes at the other, 

 according to the nature of the spark. 



The result obtained with the arc discharge, viz., that the oxygen 

 appears at the negative electrode, the hydrogen at the positive, is 

 what would happen if the oxygen in the arc had a positive charge, 

 the hydrogen a negative one. As this is contrary to the commonly 

 received views of the electro- chemical properties of these gases, I 

 endeavoured to see if I could obtain any other indications of this 

 peculiarity. With this object I have made a series of experiments on 

 the properties of various gases when the arc discharge passes through 

 them. I began these merely with the idea of elucidating the par- 

 ticular point mentioned above, but one experiment has led on to 

 another until they form a series too long to be described here ; I shall, 

 therefore, limit myself to those experiments which seem to have the 

 most direct bearing on the electrolysis of steam. 



The apparatus used for these experiments is represented in the 

 figure. The arc discharge between the platinum terminals A, B was 

 produced by a large transformer, belonging to the Cavendish Labora- 



Figk 5. 



