SHIPMENT OF BULLION. 



693 



Table VII will be found the weekly production of the different smelters, their weekly 

 or monthly shipments, with the weight and average assay of bullion for the dates 

 indicated. 



TABLE VII. Shipment of bullion. 



Composition of bullion The quality of bullion differs a good deal from smelter to 

 smelter, and from day to day at each smelter, but the former difference is more sensi- 

 ble than the latter. At some works bullion is soft, with a clear surface; at others, more 

 or less hard, with a scummy surface. The difference in the quality of bullion is due 

 less to the difference in composition of the ores, which are sensibly the same, than to 

 the care with which smelting is carried on. The same furnaces and the same ores 

 will yield coarse or partly refined bullion, according to the rapidity with which the 

 furnaces run, but chiefly according to the quantity of iron reduced during the opera- 

 tion, this metal being an excellent refining agent. 



The charges for refining bullion being greater for coarse than for soft metal, it is 

 quite evident that the smelters have a direct interest in obtaining from their furnaces 

 a metal as refined as possible. The best smelting works of Leadville obtain a bullion 

 of very fair quality. 



