Abstract1Equal energy per unit mass (or volume) proved to be a valid scaling criterion for particle size distribution as well as mean particle size for geometrically similar vessels with a volume range of 4 to 1.2Binodal particle size distributions were observed. Although the coarse fraction varied as the −6/5 power of the agitation rate, the tine size was relatively independent of agitation rate.3The system with the greater drop viscosity gave a smaller fine‐fraction and a larger coarse‐fraction than the other system (IB/W).4Both systems approached equilibrium size slowly (many minutes). Equilibrium was approached more rapidly at high agitation rates. Differences were small between different tank sizes at equal energy dissipation rates per unit mass.5The average size of the fine fraction remains about the same through the run (although the amount increases). The size of the coarse fraction decreases with time. More experiments are necessary to elucidate the mechanism behind