530 EEroRT— 1887. 



silver mines of Spain were re- worked by the Arabs. jMines in Germany- 

 were opened which, until recently, have continued to yield a good supply. 

 During the six or eight centuries preceding the discovery of America, 

 Spain and Germany yielded the greater part of the silver of Europe. 



With the discovery of the New World large supplies of silver were 

 poured into Europe, chiefly from Mexico and Peru. At a later date 

 Chili and Bolivia became great silver-producing countries ; from all these 

 a steady supply still comes, and is likely to come. 



With the discovery in 1859 of the Comstock, in Nevada, the United 

 States rapidly rose into importance as a silver-producing country. About 

 1873 the production of the United States equalled that from the older 

 silver areas of Mexico and South America, and afterwards, for a time, 

 exceeded it. 



Rich silver-bearing districts were discovered in Colorado, Utah, and 

 Arizona, the yield from which helped to balance the rapid fall in Nevada. 

 But the total production of the United States has of late years only 

 slowly increased, whilst that from Mexico and South America has been 

 steadily and more rapidly rising, so that now the older silver areas of the 

 New World again stand at the head of the list. 



Silver is almost entirely obtained from veins or from irregular masses 

 associated with veins. The main exception to this is the silver contained 

 in copper ore, which sometimes is disseminated through bedded rocks, the 

 best example of which is the copper slate of Mansfeld. 



The veins may be roughly divided into those of true silver ore, 

 argentiferous lead ore — chiefly galena, and various argentiferous ores of 

 copper. So various in character are the veins, their relation to the enclosing 

 rock, and the nature of the ores, that no useful purpose would be served 

 by touching upon these questions here ; they are fully discussed in 

 Phillips's ' Ore Deposits ' (1884), to which work those wishing information 

 on the subject should refer. 



One point, however, is of so much importance to our subject that 

 attention must be especially directed to it — that is, the exceptional 

 nature of many of the great silver deposits of the United States. These 

 have been already briefly referred to, and it was pointed out that whereas 

 lodes often retain their productiveness to indefinite deptlis, these rich 

 bonanzas and chambers of ore are very irregular in their occurrence, and 

 are unlikely to continue productive to great depths or for long dis- 

 tances. 



It is possible that other deposits resembling the Comstock may exist, 

 and may some day be woi-ked ; also that other rich deposits like those of 

 Leadville may be found ; from which large quantities of silver ore or 

 silver-lead ore may be obtained. But the expectation often expressed 

 that such mines will become common and will flood the world with silver 

 is quite unwarranted. If the United States is to keep at anything like 

 its joresent production, the discovery of some such rich deposits is needful 

 to balance the loss of those now becoming exhausted ; as the mines are 

 deepened the working expenses greatly increase, whilst not unfrequently 

 (unhke the majority of gold-quartz mines) the productiveness of the lode 

 diminishes. 



slags and waste-heaps, and also from some ore freshly raised, the production of lead 

 has been from 7,000 to 10,000 tons yearly, with from 81. to HI. of silver per ton of 

 lead. Over 1,000,000^. in lead and silver have been produced from the Laurium mines 

 since they were reopened in 18G4. 



