Abstract: An apparatus and method are disclosed which allow the size of a particle suspended in a medium to be determined virtually independent of the materials'refractive index. The apparatus includes a light source, a sample holder, a detector and a spatial filter. The method of the invention comprises passing the medium containing the particle through a beam of collimated light so that the light which contacts the particle will be scattered; deterring the light which was scattered by the particles from being detected, detecting the light which was not scattered by the particle; and determining the size of the particle from the decrease in the light intensity incident on the detector.

Abstract: Superior high water containing oil continuous microemulsions and emulsions for cleaning contain defined amounts of water, one or more ionic surfactants, and one or more organic solvents so that the compositions have a low conductivity and low viscosity.