172 TRANSACTIONS OF THE 



duced, the loss in slimos, the residuary contents of the tailings; and yet 

 without these particulars it is impossible to know how the work is ])ro- 

 gressing, or to determine where errors may have been in the working, 

 and the means of improving in future operations. By the practical 

 application of scientific knowledge to a moderate extent, in one of the 

 most important mines in Washoe, the working cost in less than two 

 years has been reduced fifty per cent, and yet there is still room for 

 improvement. 



In Washoe, when the value of the ore is spoken of, the assay value of 

 the ore is meant. In rightly conducted mills, the assay value having 

 been determined, it is made a matter of debit against the ore; and when 

 the value of the j^roduce is spoken of, as seveny-five per cent, it has 

 reference to this assay value as obtained in bullion, leaving the remain- 

 ing twenty-five per cent in the slimes and tailings. 



In the gold mines of California, the value of the ore as quoted means 

 always the value obtained by working, and not as it should be, the assay 

 value. 



It is not an uncommon thing for an ore described as a fifteen dollar 

 ore, to be found to contain, on assay, as much as sevent}- dollars. This 

 is a convenient way of concealing the exceedingly^ imperfect character 

 of the operation. 



An efficient Washoe mill man would not be content with less than 

 ninety-five per cent of the assay value of the ore, or sixty-six dollars and 

 fifty cents, at a cost of say thirty dollars, leaving a balance of profit of 

 thirty-six dollars and fifty cents, instead of fifteen dollars, minus work- 

 ing cost. 



The public papers are often finding fault, improj^ei-l}', with Washoe 

 operations, expressing wonder at twelve dollar gold quartz paj-ing, while 

 thirty dollar silver ore leaves only a microscopic profit, little dreaming 

 that from want of proper definition of values the blame lays the other 

 wa}^, the comparison being really as between seventy dollars and thirty 

 dollars, instead of twelve dollars and thirty dollars. Gold quartz mill 

 men tell all inquirers that all attempts at improvement have been 

 exhausted; that the plan now in use is perfection ; yet, on careful inquiry, 

 no evidence is obtainable of anything like satisfactory exj^eriments hav- 

 ing been made in this direction. Most men that have cut the leaves of 

 a scientific book believe themselves qualified to undertake imjjortant 

 experiments; but the most experienced experimenter alone knows how 

 difficult it is to obtain accurate results from experimental operations. 



Miners and mill men, meeting together, may mutually benefit each 

 other b}' comparing the results of their observations, correcting errors, 

 extending information, and devising means by conjoint action, sharing 

 expenses of making further improvements by emploj'ing experienced 

 experimenters to work out processes, or to define the peculiar applica- 

 bility of already known processes to peculiar localities and dilferent min- 

 erals. Extension of mining operations may confidently be anticipated 

 from such conjoint action ; and this is great!}' to be desired for the pur- 

 pose of increasing the demand for labor, the consequent increase of pop- 

 ulation, with the attendant benefits of improved roads, and enlarged 

 home market for the consumption of agricultural productions. 



