10 



Art. 11. — K. MatsTino : 



FIGr. 3 



4 000 



For the monovalent ions, sodium chloride, potassium 

 chloride, potassium bromide, potassium nitrate and sodium 



leuciate were used, the 

 same limiting concentrations 

 were obtained except the 

 last one. For the divalent, 

 barium chloride, nickel 

 sulphate strontium nitrate, 

 calcium chloride, cobaltous 

 chloride, ferrous sulphate, 

 zinc sulphate, copper sul- 

 phate and zinc acetate were 

 tested, tlie values of the last 

 two salts were very different 

 to those of the others, and 

 even comparing the values 

 of Zn" both obtained by 

 using zinc sulphate and 

 zinc acetate, a difference 

 was recognized. In the case 

 of copper sulphate it is clear 

 that the ionisation is not so 

 og{ d encj.) simple as we consider. 



namely, Cu SO4 aq. = Cu • • + SO/'. It is possibly a complicated, one. 

 Considering tlie fact that an old aqueous solution of copper sul- 

 phate reacts acidic, the idea of tlie following partial hydrolysis is 

 reasonable 



2CUSO4 + 2H2O = Cu,(0H)2S0,, + H,S0, 



But the author thinks that complex such as Cu(SOJfl;(H._,0)?/ 

 is possible. For the trivalent, cerium sulphate, aluminium 

 sulphate and chromic sulphate were used and the last two gave the 

 same value, but the first one was different. As tetravalent ions 

 zirconium cliloride and thorium nitrate were used. The limiting 

 values ol)tained by these two salts were not only in disagreement 

 with theiïiselveè, they were not suitable for the tetravalent ions. 



