Abstrmct -The significance of organic electrosynthesis on mercury elcctrodcs both for laboratory scale preparations and for the interpretation of electrode mechanisms was described. The behaviour at a dropping mercury electrode was compared with that at a stationary hanging mercury drop and at a large-area stirred mercury electrode. The validity of Delahay's equation for the half-wave potential at a large-area stirred mercury electrode and Karp-Meites' equation for the difference between the half-wave potential at a dropping and a large-area stirred electrode was verified. (Scorbaminic acid is obtained electrolytically in a pure form and more easily than by a chemical reaction. In a similar way dehydroaacorbic acid can be obtained in a considerably higher yield by anodic oxidation.) The inhibitory effects of the electrolysis products on the electrode mechanisms were described. These sometimes make an electrolytical preparation impossible. A new spherical electrolysis cell for preparative electrolysis and for recording i-E curves with a large-area mercury electrode and with a dne was constructed. The value of s,, can be varied from lo-' to INTRODUCTtON It is a well-known fact that electrolytical techniques