AbstractA coaxial‐cylinder viscometer with novel drive, control, and recording features was developed. It is capable of measuring many of the rheological properties of fluid systems over a wide range of viscosities and shear rates. The instrument is load‐independent and thermostatically controlled, and has good frequency response. The viscometer can be driven according to a variety of input wave forms either unidirectionally or in an oscillatory mode about zero with the output fed into anX‐Yrecorder. A continuous shear rate/shear stress flow curve can be obtained in less than 3