Flotation of Minerals, Part II. 303 



2. Agitation with air each of the various contaminants alone. 

 The results of these experiments are given below : — 

 Agitation with air and 60 c.c. of water and 10 c.c. of each of 

 the contaminants : — 



1. Saponine (most persistent froth). 



2. Naphtha. 



3. Kerosene. 



4. Austral machine oil. 



5. Oleic acid. 



6. Turpentine. 



7. Phellandrene. 



8. Eucalyptol. 



9. Gasolene. 



10. Alcohol. 



11. Acetic acid. 



12. Glycerine (practically no froth). 

 Agitation with air, each of the various contaminants alone : — - 

 The order in this instance is practically the same as that in 



the series where one drop of the contaminant to 60 c.c. of water 

 was used. The froth produced is, however, less than when the 

 water is present. 



It is difficult to reconcile these three series of results. The 

 variations may be due to the varying gas and liquid attachments 

 under the different conditions. 



It being apparent that the opacity of the various mixtures of 

 oil and water after agitation w^ould afford some indication of the 

 measure of attachment of one to the other, the following series 

 of opacity observations were made. 



In each case one drop of the contaminant was added to 

 60 c.c. of water and agitated with air, and after standing the 

 opacity of the solution due to the emulsion formed was observed. 



1. Oil of winter-green: greatest opacity. 



2. Turpentine, cotton-seed oil. 



3. Residual oil from rectification of eucalyptol. 



4. Austral machine oil. 



5. Phellandrene. 



6. Kerosene. 



7. Naphtha. 



In the case of the other substances a clear solution resulted. 



