1854.] Examination and Analyses of Copper ores. 477 



wall formed only the upper curve of a building of considerable 

 elevation tliat had been covered in process of time, and he further 

 trusted that deep digging would reward the explorer with new 

 relics, as in the case of the Manikyala tope. In consequence of 

 this I sunk my excavation till I came to the absolute base of the 

 foundation. 



The notes on the plan appear to explain all that need be said 

 about the rest of the undertaking, but I may mention that I should 

 be disposed to assign a considerably more modern date to the plat- 

 form pedestals of the statues of Buddha, than to the monastery itself. 



Examination and Analyses of Dr. Campbell's Specimens of Copper 

 ores obtained in the neighbourhood of Darjeeling. — By Heney 

 Piddington", Curator Museum of Economic Geology. 



Dr. Campbell, at my request, has been good enough to send us 

 down large despatches of twelve seers each of these ores as found, 

 so as to enable us both to judge accurately of the nature of the 

 rock in which they occur and to sample them fairly. By sampling 

 is meant, amongst metallurgists and smelters, the taking of fair 

 average samples from a heap of ore, so as to obtain fair results in 

 the reduction or analysis. It is a circumstance which leads to much 

 deception that those who forward specimens only send choice ones, 

 and the assayers again too often neglect this process of careful samp- 

 ling which is a tedious one and requires judgment and great care. 

 I. — Pushak Ore. 



This ore, as sent, may be described as a tough, generally fine- 

 grained, and slightly contorted hornblende slate; passing into a 

 massive hornblende rock ; the copper and iron pyrites beiug dispersed 

 through it, or sometimes in laminae, like the mica in gneiss. Grene- 

 rally the whole may be called a pyritous hornblende slate. 



There are also a few specimens of copper and iron pyrites in a 

 hard quartzose micaceous rock intersected by thicker laminae of 

 hornblende. This rock I should, call a tough, pyritous, hornblendic 

 mica slate. 



