( 350 ) 



tains chlorine to a large extent. The potential tluctuates, with shocks, 

 between 7 and 7.4 volts. 



Next a 0.68 N. -solution was taken and electrolysed with 0.3 amp. 

 and 7.75 volls; the matter is now quite ditferent and the same as 

 that observed in the electrolysis of a 2 N. -solution with 0.46 amj). 

 and 7.6 \olts. In this latter case were formed iwincdlatftlii^ at the 

 positive pole, large gas-bubbles, which ascend /;// jiU ami starts, 

 while a continuously and slowly ascending stream of small gas 

 bubbles is noticed at the cathode. At the same time is formed at 

 the liquid-meniscus above the anode a lurbid looking drop, which, 

 gradually increasing in size, detaches from the meiiiscus and falls 

 down on account of its much greater density. Later, it was found 

 that an 8 N solution of the acid gives Cl^, CO^, COCl.,, and H^ and 

 Oj, bnt no liquid product. 



After 50 minutes the volume of the gas at its negatix^e pole had 

 increased to 15 cc, that at the anode, however, to 88,3 cc. The 

 anodic gas was practically coloui-less and contained Cl^, CO.^ and 

 CO but also to a very large extent phosgene COCl., as was proved 

 by its various properties and by comparison with phosgene-gas, 

 expressl}'^ prepared for this pur|>ose from CCl^ and fuming sulphuric 

 acid. 



In order to haxe a survey as to the relative velocity of the evolu- 

 tion of gas at both poles, a few observations taken from one series 

 of experiments are communicated in the table below: 



Time : Anodic gas-volume : Cathodic gas-volume : 



(in cc.) 

 7 

 9 

 10 

 10.5 

 10.8 

 11,0 



We notice that after a given time the evolution of hydrogen at 

 the cathode almost ceases. Probably the hydrogen is used up for a 

 reduction and as the whole of the liquid present in the u-tube is strongly 

 charged with phosgene and chlorine and a considerable quantity of 

 HCl is also formed therein, it is vei-y probable that this JI^ is ab- 

 sorbed to form HCl. In these experiments the potential fell continu- 

 ously until the end value of 7.25 Volts was reached. 



