CHEMISTET OF THE WASHOE PEOCESS. 285 



gentiferous ores by the Washoe process. They throw some light, however, 

 upon several important points. 



In considering the results, as shown in the tables, the most marked fea- 

 ture is the difference in the yield of the gold and silver bullion extracted from 

 the two ores relative to their assay value. 



There is, with but one exception, in every trial of the Kentuck rock a 

 higher yield than the requirements of the mines demand of the mills, and, in 

 most cases, it is very much larger than is usually returned under the most 

 favorable circumstances, in practical operation. This is probably owing, in a 

 great measure, to the large amount of mercury employed in proportion to the 

 quantity of ore. 



The Kentuck also gave as favorable results where mercury alone was 

 used as when chemical agents were added. This proves very decidedly the 

 ability of quicksilver aided by heat and iron to decompose the purer and 

 easily reducible argentiferous minerals. 



With the Savage ore it may be observed that the yield is in all cases not 

 only very much below that from the Kentuck, but lower than the average re- 

 turns from the mills upon ores that are not first subjected to a roasting pro- 

 cess. This is undoubtedly due to the large percentage of blende and galena 

 present, with which the precious metals are in combination. The use of chem- 

 ical agents shows a decided improvement in the production of bullion from 

 such ores as contain large quantities of base metals. The application of salt 

 and sulphate of copper did not increase the loss of mercury, although in many 

 charges large quantities were present in the pulp. In the experiments con- 

 ducted, with every possible precaution to repeat the precise conditions of a 

 charge, using the same quantities of salt, sulphate of copper, and mercury, the 

 results differ as widely as in those cases where the amount of chemical agents 

 employed are much less, or entirely abandoned. The cause of these great dif- 

 ferences in the yield of bullion must be sought elsewhere than in the varying 

 amounts of the chemical agents used, however important they may be, in cer- 

 tain cases, in aiding and assisting decomposition. A favorable yield undoubt- 

 edly depends more upon the native condition of the mercury than anything 

 that is usually added to the pulp. 



Charges 8, 9, 10, 11, of the Savage table, ran only four hours, which may 



