44 MINERALOGY. 



tin- ware is iron in the form of sheets covered with tin, 

 which does not oxydize as readily as tin does. The chief 

 tin mines are at Cornwall, in England, in the island of 

 Banca, in Malacca, and in Austria. It is supposed, from 

 some allusion in ancient history, that the Cornwall mines 

 were worked some centuries before the Christian era. 



83. Zinc. This metal never occurs native. I have al- 

 ready noticed its chief ore, the sulphuret, in 57, and the 

 sulphate in 58. The other ores which are at all promi- 

 nent are the red oxyd and the carbonate. For the uses 

 of this metal I refer you to 198, Part II. 



84. Antimony. This metal is occasionally found na- 

 tive. Its usual combinations are with sulphur, or with 

 sulphur and lead together. It is sometimes also com- 

 bined with oxygen, arsenic, lime, nickel, silver, and cop- 

 per. The chief use of the metal is in the composition of 

 type-metal. In medicine there is used a double salt, in 

 which antimony is one of the bases, the tartrate of anti- 

 mony and potash. 



85. Cobalt. There are two arsenical ores of this met- 

 al that is, ores in which it is combined with arsenic. 

 Zaffre is a beautiful coloring material prepared from the 

 ores of cobalt. Smalt is glass colored with zaffre and 

 reduced to a fine powder. This is used to give a deli- 

 cate blue tinge to writing paper and to linen. 



86. Nickel. Native nickel is never of terrestrial or- 

 igin, but it is one of the ingredients in the alloy which 

 we have in meteorites, as stated in 71. It has two ar- 

 senical ores, a carbonate, various compound sulphurets, 

 etc. German silver, so called, is an alloy of copper, 

 nickel, and zinc. 



87. Bismuth. This is found native, and also combined 

 with oxygen, carbonic acid, silica, and the metal tellu- 

 rium. It is an ingredient in the most superior kind of 

 type-metal, in the " mosaic gold," and in an alloy used 

 in soldering pewter. Most of it comes from one locality, 

 Schneeberg, in Saxony. It is obtained from the rocks 



