A generalised method of cakulating the transients due to crystal growth processes is presented which allows separately for ingestion due to the acts of nucleation and crystal growth. General equations for two-and three-dimensional nucleation and crystal growth are derived and compared to the special cases which have been obtained previously. LIST OF SYMBOLS nucleation rate constant (nuclei cm ' s _ ') rate of conversion of one site into a nucleus (s-l) expectation number of the coverage expectation number of the coverage of a site for nucleation the Faraday (C mole-') height of a monolayer of deposit (cm) current density (A cm-') dimensionless current parameter rate constant for crystal growth in the direction parallel to the substrate or rate constant for hydrogen evolution at the edges (moles cm-' s-') rate constant for crystal growth in the perpendicular direction to the substrate or rate constant for hydrogen evolution on the top surfaces of growth centres (mole cm-* s-') molecular weight (g mole-') number of nuclei at time f which would have kn formed in the absence of subsequent growth and overlap (cm _ *) total number of preferred sites (cm-*) radius of a growth centre (cm) fractional area of the substrate covered by the deposit the "extended area" of the substrate covered by the deposit neglecting the effects of overlap of growth centres time (s) dimensionless time parameter time (s) radial distance from a representative point (cm) number of electrons transferred per molecule of reactant dimensionless parameter relating the rate of nucleation to the rate of crystal growth coverage of the electrode by the deposit density of the deposit (g cm-') a characteristic time (s)