416 Dr. Meyer Wilderman on the Connexion between 



the obtained results are as good as we could expect them to 

 be, 



In equation (A") lg ^ is = lg ^ 2 (for water), ire. 



(A) may be written 



which is the connexion between solubility C at any tempe- 

 rature T, g, A, T /? and T . In the same way in equation (B /r ) 



MM./ 

 lg p^ =lg' >09 m /g - (for water), and (B /; ) may be written : 



M.Z 



fe^^r^^-w+i^ 



[T] T w y ' &v //; u; ' e 0-02T /2 - 



which is the connexion between solubility [C] at any tem- 

 perature [T], g, I, T /// and T '. Taking the same point on 

 the solubility curve, C = [C], T= [TJ, we get 



9 ( l l y 1o . T ///- T o' | i Q . l - T o ( c\ 



2x2*3026 v T / ~"T / J~ ig T -T, +lg 0y s «.X'" lw 



2/m's eguation gives the connexion betiveen all the constants : 

 the heat of solution g, the latent heat of melting A, the latent 

 heat of evaporation I, freezing-point and boiling-point of the 

 pure solvent T and T(/, and the freezing-point and boiling- 

 point of the saturated solution of any given substance in the 

 presence of an excess of the dissolved substance in the solid (or 

 liguid) state T y and T //r 



Example: Boric acid in water: ^ = 5400 (J. Thomsen). 

 T /// = 375°'3, T, = 272°*415, T = 273, T '=373° (at 760 mm.), 

 /= 536*35 (Regnault), A = 80 (down to 79, according to 

 different investigators). 



We get for the above equation (0) : 



1-18 = 1*15 (when A = 80 cal.) 

 1-18 = 1-16 (when X=79 cal.). 



Calculating any of the above constants, if it be unknown, 

 from the rest, we get 



g=5263 instead of 5400 obs. (when A = 80) 



/ = 574-9 instead of 536*35 obs. (when \ = 80) 



A = 74*61 instead of 80 (79) obs., &c. 



Thus we can calculate the solubility curve when T, and 

 T //; or T, and g, or T y// and g are known. 



