330 Kenneth A. Mickle: 



No doubt these results could be greatly improved upon under 

 better working conditions and by working on a larger scale. 

 For instance, when working with a deeper flotation vessel, the 

 lighter particles in the lead product have a better opportunity 

 to settle, and are not so likely to be carried over mechanically 

 with the flotation product. On refloating the zinc product, more 

 lead can be separated as an unfloated residue. 



The writer wishes to acknowledge the suggestions and advice 

 in this work by Messrs. Donald Clark, A. J. Higgin and T. G. 

 Greenway. 



