Kinematic viscosity of oil samples is measured following the ASTM D445 method. For the measurement Canon-Fenske viscometers are used. The time that takes to oil to travel through a capillary tube of the viscometer under the force of gravity at a temperature of 40^oC is recorder. This value is converted to kinematic viscosity when multiplied with a calibration constant provided with the viscometer, or determined after proper calibration.