.[ 306 ] 



afterwards treated in the fame manner as before 



faid, in fpeaking of the grey copper-ores (Seel. 



xli.), the metal will foon be produced. But, if the 



ore is poor, the product after the firft fcorification 



muft be brought intofufion, and afterwards melted 



with fome frefh borax, in order to calcine and ico- 



rify the remaining portion of iron •, after which it 



may be treated as mentioned in Sect, xli. 



The copper will, in this lad cafe, be found in a 



Ycry fmall globule. 

 » 



SECT. XL I II. 



The copper is not very eafily fcorified with this 

 apparatus, when it is melted together with borax j 

 unlefs it has firft been expoied to the fire by itfelf 

 for awhile, in order to be calcined. When only 

 a little of this metal is diffolved, it inftantly tinges 

 the flag of a reddifh brown colour, and moftly 

 opaque j but as foon as this flag is kept in fufion 

 for a little while, it becomes quite green and trans- 

 parent : and thus the prefence of the copper may- 

 be difcovered by the colour, when it is concealed 

 in heterogeneous bodies, fa as not to be difcovered 

 by any other experiment. 



SECT. XLIV. 



If metallic copper is melted with borax by a flow 

 fire, and only for a very little time, the glafs, or flag, 

 becomes of a fine tranfparent blue or violet colour, 

 i-nclining more or lefs to the green •, but this colour 

 is not properly owing to the copper, but it may ra- 

 ther be to its phlogifton ; becaule the fame colour 

 is to be had in the fame manner from iron : and 

 thefe o-laffes, which are coloured with either of 

 thvfe two metals, foon lofe their colour, if ex- 



pofed 



