found in Western India. 353 



they mix it with moist cow- dung,' and this mixture being made 

 into balls is placed in the sun to dry. When this has been 

 accomplished the lumps are burnt, after which they are not 

 broken, up, but being mixed with an equal quantity of char- 

 coal and as much iron filings, are put into a crucible, and a 

 strong heat kept up by blowing with a leathern bellows till 

 the dross separates and the copper settles at the bottom in 

 the form of a solid disc. This product is again heated with 

 charcoal until perfectly pure copper is produced*." 



The mineral possessing greatest interest amongst those 

 above enumerated is the sulphuret of cobalt. It is found in 

 the copper mines in considerable abundance, and exists in a 

 primitive schist in^ the form of bands and disseminated grains, 

 the colour of which is a steel gray inclining to yellow. The 

 grains appear to be crystallized, and are probably the cube 

 and its derivatives. What is particularly remarkable in this 

 ore is its purity, so far surpassing in this respect any that, so 

 far as 1 am aware, is to be met with anywhere else. The 

 only substance in combination with it, after separation of the 

 matrix, is an iron pyrites, which is however but mechanically 

 mixed, and so highly magnetic as to be readily removable by 

 the magnet. The relative proportions in which these two 

 exist are — 



Cobalt pyrites .... 90*78 per cent. 

 Iron 9-22 



The iron pyrites consists of black amorphous granules with- 

 out metallic lustre, and, as above stated, it is highly magnetic, 

 having at the same time the low specific gravity of 2*58. It 

 gives on analysis — 



Iron 62*27 per cent. 



Sulphur 37*73 



The analysis was carefully made, and repeated for verifica- 

 tion, so that, notwithstanding the specific gravity is so much 

 lower than that assigned as characteristic of iron pyrites, there 

 can be no doubt such is the constitution of this constituent of 

 the ore in question. 



The cobalt pyrites exhibits the usual characteristic reac- 

 tions, generally subject to some modifications, which do not 

 deserve notice, as I found them to be mostly owing to the 

 high temperature at which my experiments were made : one 

 however is rather remarkable, and not assignable to this cause, 

 but probably to the particular natural constitution of the 

 mineral, which, as I have found, in other cases modifies the 

 behaviour of substances occasionally. 



Ferrocyanide of potassium produces in acid solutions a 



* This description is the translation of a native one given to me with 

 the minerals. 



