Double-diffusive processes, both of the 'salt fingers' and 'double-diffusive layers' type have been investigated in the laboratory using glycerine-water mixture as the fluid medium. The experiments indicate great disparities in the time scales and some in the length scales of resulting structures, when compared with those using water under identical salinity and sugar-contrasts. The results are of interest in fields of science other than physical oceanography, such as geology, where double-diffusive phenomena appear to have their counterparts and could be important in such problems as small-scale mixing in hot viscous bodies of magma.