AbstractIn order to provide experimental material for a future test of the extended law of corresponding states formulated by Kestin, Ro, and Wakeham, we report here measurements of the viscosity of several binary and ternary mixtures of polyatomic gases with monatomic and polyatomic gases. All measurements were performed at atmospheric pressure from 25°C to 200, 600, or 700°C, as the case may be. Measurements were performed with the aid of an oscillating disk instrument, and the accuracy ranged from ±0.1% at 25°C to ±0.3% at 700°C. The systems covered, included CO2with He, Ne, Ar, N2CH4with He, Ne, Ar, N2, CO2, and N2 Ar  CO2as well as C