138 OBSERVATIONS ON THE GEOLOGY OF THE 



There the tin ore occurs in beds of streams mixed with sand. The 

 natives do not dig mines to get at it, owing perhaps to its being of little 

 value at such a distance from the coast. They have, however, by their 

 own accounts, valuable lead ores, which they reach by deep shafts. 



In Captain Forrest's time, when Junk-ceylon was visited by numerous 

 native traders, the mines yielded an average annual quantity of five hundred 

 tons of tin. But as the population has been reduced to about six thousand 

 souls, and as the Siamese have mines closer to their capital, a very small 

 supply only is now taken from the island. Perhaps it may be rated at one 

 hundred Bahars of 446 lbs. averaged each. A Chinese smelter informed 

 me, that he could aiFord to produce tin at a cost of one-half at the utmost 

 of the market rate. The miners dig pits of from twelve to twenty feet deep ; 

 but seldom venture a lateral shaft. The ore is generally in round or 

 oblong masses, with well defined crystals, and in a matrix of quartz, or 

 bedded in masses resembling half decomposed granite, yet of considerable 

 hardness. 



The furnace in which the pounded ore is smelted, is made of a com- 

 pact of clays and earths, is oblong in shape, and about three feet high. 

 Alternate layers of ore and charcoal are put into it, and the usual hori- 

 zontal tube bellows of the Chinese, is kept incessantly at work during 

 four complete days (of twenty-four hours) and one night, when the fur- 

 nace is cleansed. After some hours labor, the tin makes its appearance, 

 and is run into moulds, and the furnace is fed with more ore and fuel. 



The Hay of Phwiga, which stretches N. E. from Jimk-ceylon, is re- 

 markable for the magnificent rocks, with which it is studded. At the 

 distance of ten miles, they appear like huge artificial pyramids ; but on a 

 nearer approach, their outlines change to columnar, or massive. The 



principal 



