MINING IN SOUTH AMERICA. 



S75 



extraordinary rich lode may be too small to be 

 worth the expense of working, while a very large 

 poor lode may be worked with profit. 



But, besides these observations, the physical cha- 

 racter of the lode must be considered ; for the fis- 

 sure is seldom filled with ore, it contains also 

 quartz, mundic,"^ &c. &c. and is occasionally a 

 strong box which contains no riches at all. 



It is therefore evident, that besides the size of 

 the lode, and the assay, the average quantity of ore 

 it contains is also to be considered ; because a large 

 lode, with an occasional bunch (as it is termed) of 

 rich ores, may not be so worthy of working as a 

 smaller lode with a number of bunches of poorer 

 ores. There is also another material question, — 

 whether the lode is getting richer or poorer as it 

 dips ? For a large lode, with rich assay, and fre- 

 quent bunches, but diminishing in value, may be 

 calculated at less value than a smaller lode with 

 poorer assay, less frequent bunches, but increas- 

 ing in value. 



There are many other considerations, but the 



above, perhaps, will satisfy those who have not 



* The Cornish term for sulphurets of arsenic, iron, &c. 



T 2 



