82 ELECTROLYSIS AND ELECTROS YNTHES1S 



at the negative pole (by the alkali present), while at 

 the positive pole the solution remains clear. 



As Lassaigne has shown, pure albumen in aqueous 

 solution is a non-conductor of electricity; the addition 

 of salts or acids is therefore necessary in its elec- 

 trolysis. 



ii. Electrolysis and Electrosynthesis with 

 Alternating Currents. 



If the polarity of the current does not change 

 altogether too rapidly, since oxidation and reduction 

 occur successively at each pole, it is possible to 

 accomplish electrolyses and electrosyntheses with 

 alternating currents. Experiments with this end in 

 view have been made by Drechsel. 1 Dehydration is 

 a case of simultaneous reduction and oxidation. The 

 supposition that in living organisms carbamide is pro- 

 duced from ammonium carbamate by the splitting off 

 of water prompted Drechsel to make experiments in 

 this direction. 3 



If an aqueous solution of ammonium carbamate was 

 electrolyzed with a current from a battery of 4-6 

 Grove elements and platinum electrodes were used, 

 carbamide was obtained independently of the elec- 



Journ. prakt. Chem., 22, 476. 

 Ibid. 



