58 PRODUCE OF THE MINES CHAP. XVIII. 



than the year 1556; but it is very reasonably be- 

 lieved that the first years which followed the 

 discovery of the veins were the most productive 

 in riches/' Although the actual amount in the 

 first ten years must be a matter of doubt, yet 

 some judgment may be formed from the suc- 

 ceeding twenty-three years, from 1556 to 1578, 

 of which the accounts have every appearance of 

 veracity. 



The Emperor Charles the fifth granted to his 

 celebrated secretary of state, Don Francisco To- 

 mas de los Cobos, for two lives, a maravedi on 

 each marc of silver raised in Potosi. This gave 

 rise to the tax afterwards imposed of a fifth of the 

 produce. The account of the Cobos, the impost 

 having taken the name of the person in whose 

 favour it was first granted, from the years 1556 to 

 1578, gives, as the amount of the tax, nine millions 

 eight hundred and two thousand two hundred and 

 fifty-seven pesos, and consequently the treasure 

 produced must have amounted to forty-nine mil- 

 lions eleven thousand two hundred and eighty-five 

 pesos or dollars, or annually to two millions one 

 hundred and thirty thousand nine hundred and 

 twenty-five pesos, or about four hundred and forty 

 thousand pounds sterling 1 . 



Sandoval, Ulloa, and Solarzano, all of whom 

 are quoted by Humboldt, would lead us to sup- 



1 Diccionario de Hacienda, vol. i. page 102. 



f 



