Viscosity measurements in the diamond anvil pressure cell.

The viscosity of liquids can be measured in the diamond-anvil pressure cell utilizing a falling-solid sphere method and the ruby technique for pressure measurement. The pressure dependence of the viscosity of a 4:1 mixture (by volume) of methanol-ethanol was determined to 70 kilobars. The accuracy of the method is estimated from measurements made on a fluid of known viscosity.