SGIENTIFIC NEWS. 363 



The substances that accompany the metallic ores (or the Geological 

 vein-stones) vary considerably, not only in different mines, but Society, 

 in different parts of the same vein ; and it is from these, and 

 not from their metallic contents, that the miner's nomenclature 

 of the veins is derived. 



Gossan is a friable substance of a loose texture, consisting 

 of clay, mixed more or less with silicious matter, and coated 

 or tinged with oxide of iron. Its colour varies from light yel- 

 low to deep and brownish black. A gossany lode is more 

 common than any other, and is considered as promising both for 

 copper and tin. 



When quartz predominates, the vein is called sparry ; and if 

 the quartz is considerably compact, it is looked upon as a very 

 unfavourable indication, more especially if the vein becomes 

 narrower as it descends. 



If iron pyrites abounds, the vein is said to be mundicky^ 

 When this substance occurs at a shallow level, it is considered 

 as not unpromising, more especially if mingled with copper or© 

 as it descends, 



A vein containing a large proportion of chlorine, is termed 

 a peachy lode, and promises for tin rather than copper. 



A vein is said to be Jlookany when one or both of its sides 

 is lined with bluish white clay. It sometimes is so abundant, 

 as to occasion considerable difficulty and expence to prevent it 

 from slipping down, and obstructing the works. 



When the contents of a vein consist of a hard compact 

 substance, of a greenish or brownish colour, which appears 

 to be chiefly a mixture of quartz and chlorite, the vein is de- 

 nominated caply. Tin is often found in it, copper rarely. 



When the ore, whether of tin or copper, is found in de« 

 tached stones or humps, mixed loosely with the other contents 

 of the vein, it is termed a pryany lode. 



A vein abounding in blende, is called a Black Jack lode, and 

 is considered as unpromising for tin, but a good sign for copper. 



When a vein contains granite in masses or blocks, or in a 

 state of semi-decomposition, it is termed a growan lode j and 

 is generally considered as more promising for tin than for cop- 

 per. Of late, however, many rich veins of copper have been 

 found in the granitic districts of Cornwall. 



The experienced miner by no means implicitly relies on even 



thd 



