Abstract1)The consistency of a plastic suspension of the Bingham type was characterized by deriving φ‐τ diagrams from theD‐τ diagrams.2) In the case of the plastic suspensions of carbon in mineral oil it is deduced from the φ‐τ relation that the temperature coefficient of the consistency is determined almost entirely by the medium of suspension.3) Attention is called to the large errors caused by the turbulence occurring during measurements at high shearing stresses.4) In order to describe the curved part of aD‐τ diagram more exactly by means of constants, the concept of liquidation tendency is introduced. This liquidation tendency can be read off directly from