A vertical cone-and-plate rheometer (K. Weissenberg, 1948, and improvers since) for viscoelastic liquids in which the cone can twist through a measured angle while the plate is rotated at speeds providing shear rates to 100 s−1. The cone and plate are enclosed in an oven that provides control of the sample temperature. The plate shaft rests on a ball bearing at its bottom which in turn rests on a force transducer. Thus it is possible to measure both the restoring torque on the cone and the normal force on the plate. The first provides an estimate of the liquid's viscosity while the normal force gives an estimate of the normal stress.