Another famous mining centre in those early days, just as it is at present, was Zacatecas, and its name alone conveys the idea of silver and gold. In 1546 it was, that a lieutenant of Cortes, traversing the country, arrived there, observed its promise of mineral wealth, and formed a settlement. So rapidly did the place become renowned that, forty years afterwards, a Royal Charter was given to the city, and a coat of arms, with the title, "Noble and Loyal." The curious archives of the Alvarado Mines--they were worked by Fernando Cortes--which were kept, and which show the care in these matters exercised by the Spaniards, still exist; as is the case, indeed, with the records of many of the great mining centres of Mexico and Peru. Here it is shown that an enormous output of silver was made, the total from 1548 to 1867 amounting to nearly eight hundred million dollars. The great lodes of the famous mining centre of Pachuca, which at the present day are the most productive, were discovered by the companions of Cortes soon after the Conquest. But knowledge of the great wealth in silver there was held by the Aztecs, who, in fact, showed the main veins to the Spaniards. It was here that Bartolome de Medina discovered the famous method of treating silver ores by amalgamation with quicksilver, known as the _patio_ process, in 1557. An improvement on his invention came from Peru, in 1783, which was the use of mules instead of men in treading out the crushed ore. From far-away Peru other matters had come, as the quicksilver from the great Huancavelica mines, the mercury necessary for the process. And the beautiful Peruvian pepper trees, which were brought to ornament the _plaza_ of Pachuca by one of the last of the Viceroys from Lima, form another reminiscence of the sister land of the Incas, in Mexico. There is at Pachuca a link with the world of Anglo-Saxon mining--the cemetery where to-day lie the bones of clever Cornish miners, who, in the time of the British revival of Mexican mining, taught the native their more useful methods. There lie these hardy sons of Cornwall, "each in his narrow cell," within the foreign soil whereon he had laboured.