Constant in the Kinetic Theory of Oases 449 



while the angle taken by Prof. Chapman is 



We propose to calculate the effect of this difference on the 

 viscosity and diffusion problems. Two laws of force will be con- 

 sidered : 



(1) The inverse power law. 



(2) A shell of constant force from r = o-ia to r =- iZ = aa-^^., where 

 a is a moderately small number. 



§ 4. . Calculation of the Correction in the angle x- This correction 

 is seen from the figure to be negative and equal in magnitude to 



iP = BQN. 



T 



Let { — / (r)} be the acceleration of B in the relative orbit. Thus 

 (f) (r) being the potential of the intermolecular field, 



f(r)= d'^i^) ^ m^ + ^2 d<i> (y) 

 dr rn^rn^ dr ' 



O (r) being introduced for convenience merely. In our case, the 

 forces being attractive, / (r) and <I) (r) are positive. 



Let w be the perpendicular onto the tangent at any point. 

 Then we have 



drW)^~ c^^^^'^' 

 where c is the angular momentum pV. Integrating: 



^2 ^2{' ^ FW 



29—2 



