4G9 COMMERCIAL DESCRIPTION OF The quantity of tin which the mines of Banca are capable of affording is immense, as the supply of ore is nearly indefinite, and the facility of working great. About the year 1750, or forty years after their first discovery, they yielded, it has been cal- culated, much above 1:^0,000 slabs, or G6,000 pi- culs, 5870 tons. From internal anarchy, — mal- administration, — the exhaustion of some rich mines conveniently situated, — the monopoly of the Euro- pean government, — the restrictions upon commerce occasioned by the state of war among the European nations, — and in some respect, perhaps, from the forced competition of the tin of Cornwall brought to China, the quantity produced of late years has greatly diminished. About the year I78O, the produce had fallen to 30,000 piculs, or to less than half its maximum, and from 1799, until the Bri- tish conquest, seldom exceeded one-third of this last amount, or 10,000 piculs. Of the causes which have led to the diminished production of tin in late years, the only one that deserves a particu- lar examination is that which ascribes it to the exhausted state of the mineral strata. To this cause, however, I am inclined to ascribe a very limited effect indeed. It is necessarily with mines as with new lands, in countries where both are abun- dant and fertile. No economy is observed with regard to either. The more fertile beds of mi- nerals, those which afford the greatest quantity 10
