Samenvatting
In this article the author gives various methods to judge the mixing of solid matters. First he contemplates the definition of ideal mixing. The idea ideal mixing mostly is defined for 2 components of the same grain size. This definition is also valid for more than 2 components, but when the components have different grain sizes the definition is not valid. But the distribution of the number of particles of a component in a sample taken at random can still be taken as a base.