The caste system has evidently been more flexible, in terms of appropriate work for Brahmins, than one might expect. Records from the classical and medieval periods in India mention men of the Brahmin class performing work other than carrying out priestly duties or teaching about religion.
Spanish conquerors discovered that South America was home to rich veins of silver and silver ore, and they mined that wealth enthusiastically; according to the Silver Institute, an industry trade group, 85 percent of the silver produced worldwide came from Bolivia, Peru and Mexico between 1500 and 1800.
In 1858 the great silver rush began in Napa Valley, and miners eagerly flocked to the eastern hills. In the 1860s, mining carried on, in a large scale, with quicksilver mines operating in many areas of Napa County. The most noted mine was the Silverado Mine, near the summit of Mount Saint Helena.