1893.] 



The Electrolysis of Steam. 



93 



different vessel, I have collected the gases on their escape from the 

 discharge tube in graduated eudiometers provided with platinum 

 terminals by means of which the mixed gases were exploded in situ 

 at short intervals during the course of the experiments. This plan 

 avoids the trouble, waste of time, and risk of error incurred in 

 moving the mixed gases from the collecting tube to the eudiometer. 

 Its greatest advantage, however, is that it enables us to see with very 

 little delay at which terminals the excesses of hydrogen and oxygen 

 are appearing. As I shall have to explain below, the sides at which 

 the excesses of hydrogen and oxygen appear can be reversed by 

 altering the character of the spark, and it very much facilitates the 

 investigation of the laws of this reversal to be able to tell, with as 

 little loss of time as possible, at which terminal the excess of hydrogen 

 is appearing. 



Description of the Apparatus. 



I will now pass on to describe the form of apparatus which, after 

 many trials, was found to be the most convenient. 



This is represented in fig 2. H is a glass bulb, 1*5 to 2 litres in 

 volume, containing the water which supplies the steam. A tube, L, 

 about 0'75 cm. in diameter and 35 cm. long, is joined on to this. In 

 many cases this was fused directly on to the bulb ; I do not think, how- 

 ever, that this is necessary, and I have found no ill effects arise from 



Fig. 2. 



