An extensive series of photographs of lines of flow induced in a viscoelastic liquid by a rotating cone has been obtained for polyisobutylene in cetane at various vertex angles. Torque and thrust were measured at various angular velocities, concentrations, and temperatures. Concentrations above 5% resulted in departures from Newtonian behavior. They exhibited multiple vortices and in addition, the thrust‐to‐angular‐velocity relationships were different from those for Newtonian liquids. The higher concentrations show well defined maxima of thrust and torque at definite angular velocities.