940 



COPPER ASSAYING 



Summary of Produce of Copper Ore and Copper for each of the Ten Years ending 18"^ 

 with the respective Values and the Number of Mines worked. 



DEVONSHIRE. 



Summary for the United Kingdom during the last Ten Years. 



COPPBB ASSAYING. The substances which are submitted to assay for copper are 

 various ores of copper, slags, and other metallurgical products, commercial varieties 

 of copper and its alloys. The assays are made by the dry and wet methods. 



Dry Assay. 1. English or Cornish method. This process is very extensively em- 

 ployed in England ; all the copper ores being bought and sold by this method. The 

 mode of working by this method varies somewhat as to the manipulation, nature, and 

 proportion of fluxes, form of apparatus, and other minute details ; but it may bo 

 regarded as consisting essentially of the four following processes : 



1. Fusion for rcgulus, or sulphide of copper and iron. 



2. Boasting or Calcination of the regulus into oxides of copper and iron. 



