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LXXXIV. JYote on the Derivation of Partington's Equation 

 from the General Equation of the Ionization Isotherm. By 

 William Hughes, B.Sc, M.A* 



IN the author's paper on f ' The Application of the Law of 

 Mass Action to Strong Electrolytes" (Phil. Mag. [6] 

 xlii. p. 428) a factor was omitted from equation (4), thereby 

 rendering the algebra unintelligible. The full working is 

 as follows : — 



c 

 Divide each side of (4) by 1 + y and we get 



a 2 const. 



When n 1 =n 2 this becomes 



a 2 const 



(l-*)v(l + -0 l + f 



c has been written for b/m, and b and m signify the usual 

 constants in the equation a.= mY -{■ b. 



]S ow Tr =- Y = ^ Y = ^ 



V m tan 6 1 Ytan# ; 



where 6 has its usual significance. 



For the large dilutions to which Partington applies his 

 equation the isotherm is practically parallel to « = 1, as is 

 easily seen by plotting, say, the van't Hoff isotherm. 



Consequently Ytan#= const. 



b/Y tan #== const. 



But b/Y tan 0=^. 



Hence to a high degree of approximation 

 const. 



const. 



i + v 



Hence finally , ~c = const,, 



(i-«)v(i + y) 



and Partington's equation follows from this as shown loc. cit. 

 * Communicated bv the Author. 



