A very recent paper, referred to below as Paper I, had been devoted to the description of magnetic field effects on the structural features of nickel electrodeposits grown from a Watts solution,either pure or in the presence of small amounts of a primary brightener and leveling agent such as 2-butyne-1,4-diol (BD). The conclusions of Paper I stressed the major effect of the magnetic field which was supposed to come down to a magnetohydrodynamic forced convection close to the cathodic interface. This convection enhances those among the cathodic reactions which are likely to be mass-transport controlled, which is the case for the hydrogen electrode reaction as well as for the catalytic hydrogenation undergone by ED on the cathodic surface. The aim of this paper is to describe the results of electrochemical studies which have been carried out with the same system so as to check the validity of our assumption.