Two modifications of the cone and plate viscometer are described. The first, for measurements at low shearing stresses (10 to 100 dyn/cm²), employs a phosphor-bronze strip to apply torque to the cone. The second, a direct reading instrument for measurements at a relatively high stress (4 500 dyn/cm²), uses a small d.c. motor running at constant torque to drive the cone. The range of the first instrument is 1 to 100 poises at 10 dyn/cm², and 10 to 100 poises at 100 dyn/cm², that of the second is 0.5 to 30 poises. Their accuracy varies according to the viscosity and anomaly of the fluid under examination, but the average is about ± 5%, which is quite adequate for many purposes. The examination of a sample with either instrument, including filling and cleaning, can be completed within two minutes.