1. We adopt the notation and techniques described by James J. Duderstadt and William K. Martin ‘Transport Theory" (John Wiley, New York, 1979). Chapter 3. This textbook contains a number of references to the earlier literature.
2. The treatment follows that of Kerson Huang "Statistical Mechanics" (John Wiley, New York, 1963) Chapter 4.
3. Joel L. Lebowitz and Peter G. Bergmann, Ann. Phys. (N.Y.) 1, 1(1957).
4. H. Grad in Handbuch der Physik, Vol. XII. "Thermodynamics of Gases" (Springer-Verlag, Berlin, 1968).
5. Sometimes, in order to compress notation, we shall use the symbol ( % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaacbaGab83Day% aalaaaaa!3700! $$\vec w$$ ) to indicate the molecule whose velocity is % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaacbaGab83Day% aalaaaaa!3700! $$\vec w$$ .