464 COMMERCIAL DESCIUPTIO.V OF are cliiefly confined to the northern and western parts of it, whereas the south-eastern has hardly been touched. From one extremity to the other, the alluvial lands are ascertained to abound in beds of tin ; and from the analogy of other countries, it is beyond any doubt that the mountains abound in veins of it. To the difficult and expensive pro- cesses required for the mining of these last it is at present superfluous to look, for the alluvial lands contain the cheap and abundant supply of many ages. I shall, with the view of pointing out the great value of the mines of Banca, draw a short compa- rison between them and those of Cornwall. The whole produce of the mines of Banca, when they were wrought to the greatest advantage, was near- ly the same in numerical amount with the highest produce of those of Cornwall, Even at present their amount is equal to one half of it. But the whole produce of Banca is grain tin, a pure metal, superior in intrinsic value to block tin 2-^^ per cent. Cornish tin is obtained, with vast labour, by mining through obdurate granite, often to the pro- digious depth of many hundred fathoms ; Banca tin, by digging through a few soft strata of sand and clay, and seldom to more than three or four fathoms. To clear the Cornish mines from water, the most expensive and complex machinery is re- quisite ; to clear those of Banca, a simple wooden
