Flotation of Minerals, Part II. 307 



With 80 gms. the product of the oil and blende consisted of 

 a mass of small coherent aggregations, which on violent agita- 

 tion attached many air bubbles, but which would not float the 

 mineral. 



With 120 gms. the aggregates of blende and oil were smaller 

 and less coherent. The zinc blende at this stage seemed more 

 prone to attach air bubbles, and sho\yed a tendency to float. 



The appearance of the product was quite different from a 

 similar quantity of unoiled blende in water. 



Another series on the same lines as the above, using galena 

 and oleic acid in similar proportions to the blende and engine 

 oil, showed that the general character of the products was 

 similar to those produced with blende and engine oil. 



The oily magmas on the bottom of the bottles formed by the 

 galena and oleic acid were less viscous and flowed more freely. 

 A little free oil still showed on the surface of the water when 

 40 o-ms. galena had been added. No free oil showed with 80 

 gms. The products with 80 gms. and 120 gms. galena were 

 more coherent and less prone to attach bubbles of air than was 

 the case with zinc blende. The stage at which the small granules 

 formed was less marked with the galena than with the blende. 



In another series with heavy lubricating oil and zinc blende, 

 most of the oil was carried down to the bottom in the form of a 

 putty-like ball with the blende when 30 gms. of the latter had 

 been added. This plastic mass would nob break up on shaking 

 violently, and was not miscible with the solution. 



With 20 gms. of the blende and the oil, the product was a 

 thin plastic mass on the bottom of the bottle, and non-miscible 

 with water. A large excess of oil showed on the surface of the 

 water. 



With 40 gms. of blende, the mass or magma showed a tendency 

 to break up into small lumps, but showed no tendency to attach 

 air bubbles. The lumps were rounded and were about the size 

 of broad-beans. No free oil showed on the surface of the water. 



In another series using copper pyrites and 5 gms. heavy 

 engine oil, all the oil was carried down w4th 30 gms. of the 

 copper pyrites, to form the putty-like magma which would not 

 break upon agitation. 



