606 Mr. L. Vegard : Contributions to 





Oanc-Sugar Solution. 



KOH Solution. 



c. 



dP 



do 



dp 



.-.5?. 



1/19 



1/9 



3/17 



V4 



1/3 



1 



0-380 

 0-337 

 0311 

 0-286 

 0-260 

 0-138 



2-87 . 10 7 



5"57 „ 



8-49 „ 



11-50 „ 



14-55 „ 



31-20 „ 



0-720 

 0-720 

 0-650 

 0-700 

 0-590 

 0-320 



0-87 . 10 -7 

 1-87 „ 

 2 72 



423 „ 

 4-85 „ 

 9-45 „ 



With regard to the calculation in the case of Potassium 

 Hydrate, we must remark that such a solution is usually 

 considered to be dissociated. The solution is then not binary 

 in the strict sense of the word. If, however, the electrical 

 action between the ions is very great compared with the in- 

 fluence of gravity, we can here suppose that the pairs of ions 

 cannot be separated by the action of gravity, to any appre- 

 ciable extent. 



We can, however, not apply equation (15 b) without 

 further consideration. But equation (lie) still remains true, 

 and we can write : — 



(te) =i i R - T ' 



where i is the dissociation constant introduced by Van't Hoff, 

 and which is generally dependent on the concentration. 

 Consequently 



.dC p„ M, .dp 



O'l p h> • 1 dc 



The calculation has been carried out for the potassium 

 hydrate solution according to this formula. 



§2- 



On the Variation of the Osmotic Pressure with the 

 Hydrostatic Pressure. 

 Osmotic pressure has already been mentioned in § 1 ; as 

 also what is to be understood by it. When defined in this 

 manner, the osmotic pressure will not only depend on tem- 

 perature and concentration, but also upon the pressure to 

 which the fluid is exposed on one side of the membrane. In 

 passing through the membrane from the solution into the 

 solvent, the hydrostatic pressure will fall from p to p 0i and 



