CHAP. II. TO THE EAST OF PERSIA. 37 



feet in diameter. The passages and props are well 

 executed, but the former so narrow and low that it 

 must have been difficult to have worked in them. 

 The natural pillars left to support the roofs are 

 in some instances still effectual for that purpose, 

 and in these are still found small portions of 

 copper ore, containing particles of gold ; in other 

 instances, the supports have given way, and in 

 them are found some human bones, probably of 

 those who had been buried in the ruins. That 

 a great number of people were employed is in- 

 ferred from the numerous fragments of earthen- 

 ware which are found scattered to a great di- 

 stance around. 



It appears that only the richest ores were 

 worked, and some of them must have been 

 smelted in the mines ; for in the rubbish of one 

 of the supports which had fallen in, there has 

 been found melted copper, and the implement for 

 smelting it : some of these implements also have 

 been found on the surface near the pits. The 

 operation of crushing as well as washing the ores 

 was performed in the rivulets, and, as is supposed, 

 the latter was omitted in the rich ores, which were 

 found on elevated spots. The smelting, whether 

 in the mines or on the surface, was performed in 

 small furnaces, of which Gmelin observed near 

 a thousand in the eastern parts of Siberia. They 

 were made of red bricks, and in them pieces of 

 melted copper, from two to three pounds in 



