Both tests are considered obsolete to other measures of kinematic viscosity, but their results are quoted widely in technical literature.
In both tests, the time taken for 60 ml of the liquid, held at a specific temperature, to flow through a calibrated tube, is measured, using a Saybolt viscometer.
[2] The Saybolt universal viscosity test occurs at 100 °F (38 °C), or more recently, 40 °C (104 °F).
The Saybolt FUROL viscosity test occurs at 120 °F (49 °C), or more recently, 50 °C (122 °F), and uses a larger calibrated tube.
This provides for the testing of more viscous fluids, with the result being approximately 1⁄10 of the universal viscosity.