On Metallic Minerals. 339 



SULPHURET OF IRON. — IRON PYRITES. 



No mineral appears to be more generally distributed over 

 the world than sulphurct of iron, and it has, of course, 

 been frequently met with in this country. It is seldom, 

 however, found in any considerable quantity in one spol^ 

 when this is the case it is important, because at a trifling 

 expense it can be converted into an article of commerce 

 called copperas or green vitriol, which is a sulphate of iron. 

 The process is, I believe, as follows : the iron pyrites are 

 gathered together in heaps six or eight feet high upon 

 platforms, these are exposed to the action of the atmosphere 

 for about a twelve month, when they are found to have 

 undergone a spontaneous decomposition and a sulphate of 

 iron has been formed. This sulphate of iron being soluble 

 in water has, a large portion of it, been received into 

 troughs communicating with the platforms by pipes or 

 drains. The liquid thus obtained is afterwards evaporated 

 and sulphate of iron in a concrete state is formed. This 

 species of decomposition is effected in the following manner, 

 the sulphur combined with the iron to form iron pyrites 

 attracts oxigen from the air and passes into sulphuric 

 acid which acting upon the iron forms sulphate of iron. — 

 Some varieties of pyrites require to be roasted before this 

 decoiui>osition will take place. 



Iron pyrites is never smelted as an ore of iron unless 

 it be intimately mixed with other ores so as to be inse- 

 parable, such is the case with much of the ore at Marmora. 

 Its presence is considered injurious to ores. 



Five confiidcrabic deposits of iron pyrites have been 

 noticed, viz. on an island on the south shore of Drununond 

 Island ;* on another island off the north coast of the same 



* TliiK icUnd I1.U IdU'ly |as»t'd from uii<l< I ili< Hiiti'^li >li>iiiiiiiuii. 



