AMERICAN MINES. CHAP. xxn. 



to the end of the year 1699. From that period 

 the progress during the first twenty or thirty 

 years, though constant, was comparatively slow, 

 but towards the latter end of the century became 

 much more rapid. 



The great mine of Valenciana, which, during 

 forty years, yielded to its proprietors a clear 

 profit of from eighty-five thousand to one hun- 

 dred and twenty-five thousand pounds sterling 

 yearly, had been neglected till the year 1760, and 

 after ten years' labour and expenditure, when the 

 rich part of the vein had been reached, continued 

 for upwards of forty years to yield more than half 

 a million sterling in gold and silver. The rich 

 district of Guanaxuato, which in the years before 

 1766 yielded only three hundred and eighty thou- 

 sand ounces of silver yearly, produced in the latter 

 years of its prosperity more than one million five 

 hundred thousand. The mineral repository of 

 Catorce was only discovered in the year 1773, but 

 it yielded a very large quantity both of gold and 

 silver till 1798, when the value of the minerals 

 declined. The vein of Biscaina, though it began 

 to be worked at the beginning of the sixteenth 

 century, did not become enormously productive 

 till 176^, though in twelve years from that period 

 the owner of it had gained a profit of more than 

 a million sterling, with part of which he presented 

 to the King of Spain two ships of war, one of them 

 of one hundred and twenty guns, and, besides, 



