1835] Copper Mines of Singhdna. 58 1 



No. 1. JVo. 2. No. 3„ 

 p. Tbe copper combined with carbonic acid being, . . 30'2 39*5 18*3 

 q. will require water to hydrate it, 4*2 5'5 2*6 



The excess in b may have heen carbonic acid, partially driven off. 



The chemical composition of the three minerals may therefore be 

 thus expressed: 



No. 1. No. 2. No. 3» 



Hyd rated carbonate of copper, 52*4 68*5 3W 



Sulphuret of copper, 0* 0- ? 630 



Sulphuret of iron, 2-1 124 O'O 



Oxide of iron, silex, &c 43*5 25-1 5'3 



Loss or excess, 2*0 — 60 0-0 



100-0 1000 100-0 



The excess in No. 2, is doubtless owing to the irregularity of the 

 rocky admixture in different specimens, whereof one yielded 44, and 

 another only 13" 9 of insoluble matter, on digestion in acid. 



The richness of the last of the three minerals will more than com* 

 pensate for the increase of trouble and expence in the reduction of 

 the ore by successive roastings ; and practical miners assert, that the 

 glance or grey sulphuret is a much steadier and more plentiful ore 

 than the carbonate. 



I should add, before concluding the above imperfect analysis of 

 the Nellore copper ores, that 1 tested them in vain for silver and 

 other metals. Neither did arsenic appear to be present. 



I may here mention, that among the specimens of minerals pre- 

 sented to me by Mr. Kerr, as occurring within the copper mining 

 district, associated with the micaceous schist, are the following ; 

 corundum and adamantine spar, garnets, dark-green actinolite, red 

 chalk, manganese ; besides carbonate of magnesia, and other minerals 

 of which specimens have not yet reached me. An ore of mercury is 

 also suspected to exist in the same range of rocks. The surface of the 

 gneiss or micaceous schist, where exposed to the air, is frequently seen 

 tinged of a green colour, from the trickling of water holding carbonate 

 of copper in solution, through crevices of the rock. 



Copper Mines of Singhdna, in the Shekdwatl country. 



I take this opportunity of acknowledging the receipt of further 

 specimens of the ores of these mines from Colonel Stacy. — They 

 consist of the yellow and grey sulphurets, carbonates, and the 

 blue native sulphate in deliquescent crystals. The latter is probably 

 produced from the pyrites ; as is the sulphate of iron from its sulphuret. 

 Both of these occur also at Singhana : the sulphate, from its dif- 

 ferent tints, having the native names of pila and hara kasis, or 

 yellow and green vitriol. There is also among the specimens a mungya 

 4 F 



