50

EARLY COLLECTION OF GOLD chap. xvii.

stage of society, simple, rude, and with little re-gard to extracting the whole of the precious metalsfrom the ores. The mines had been wroughtfor the Incas , and the use of mercury had notbeen adopted till more than forty years after theconquest. The smelting was performed in smallportable furnaces or cylindrical tubes of clay,very broad and pierced with a great number ofholes. In these the Indians placed layers ofsilver ore, galena, and charcoal, and the currentof air which entered the holes quickened the fireand gave it a great degree of intensity. Thesefurnaces were moved from one elevation to an-other according to the degree of high or low wind.When it was found that the wind blew too strongand consumed too much of the fuel, they were re-moved to a lower situation. By these means thenatives obtained argentiferous masses, which weresmelted again in their own cottages. This wasperformed by a number of persons, ten or twelveat a time blowing a fire through copper tubes,from one to two yards in length, pierced with asmall hole at the extremity towards the fire, whichthus acted in the same manner as the modernblowpipe. By such processes as these, though avery large portion of the silver must have re-mained in the scoriae without combining with thegalena, yet such a quantity could be obtained as wouldsatisfy the demands of the fiscal offi cers of the Inca .