Electrolytes on Copper Colloidal Solutions. 



Table VII. 



A1 2 (S0 4 ) 3 added to Copper Colloidal Solution. 



591 



No. 



Grams of S0 4 per 

 50 ccs. Cu Sol. 



Spec. Cond. Velocity at 

 at 18° 0. 18° C. 



Coagulation. 



1 



7-7X10 -6 | +23-4X10" 5 

 . 1 J 

 67x10 ° j 12-9X10 -6 | +21-5X10" 5 



134X10" 5 ' 14-9X10 -6 ; +19-2xl0~ 5 



No sign. 



2 



3 



4 



26-OxlO" 5 20-2X10" 6 -H8-5V10- 5 1 * 











* The two samples were not retained for coagulation observations. 



It will be seen from the table that, although about 

 62 X 10"° gram of aluminium sulphate was added to 100 ccs. 

 of copper colloidal solution, there is very slight diminution 

 of the velocity, while in none of the samples was there any 

 immediate sign of coagulation — results in marked contrast 

 with those obtained when the same electrolyte was added to 

 gold and silver colloidal solutions. 



d. Potassium Phosphate. 



This salt was chosen as one representative of those possess- 

 ing a trivalent acid radical. That its action on the copper 

 is very keen is shown by the numbers in Table VIII. 



Table VIII. 

 K3PO4 added to Copper Colloidal Solution. 



No. 



Grams of P0 4 per 

 50 ccs. Cu Sol. 



Spec. Cond. 

 at 18° C. 



Velocity at 

 18° C. 



Coagulation. 



1. 







6-5X10" 6 



+25-4 xlO" 5 





2. 



1-7X10" 5 



7-8X10 -6 



+21-5X10" 5 



No immed. sign. 



3. 



35X10" 5 



8-3X10" 6 



+ 168X10" 5 



?> >> 



4. 



6-8X10 -5 



9-9X10 -6 



+ 3-lxlO" 5 



3 to 4 hours. 



5. 



102X10 -5 



11-7X10" 6 



- 4-8X10 -5 



In 2 hours. 



6. 



15-6X10" 5 



15-7 xl0~ 6 



- 7-9X10 -5 



In a few hours. 



