Traditional metal working in Mexico more. Important metal working centers include Taxco for silver, Santa Clara del Cobre for copper, Celaya for tin and Zacatecas for wrought iron. Metal working in Mesoamerica, especially of silver, gold and copper was advanced by the time the Spanish arrived, mostly concentrated in the modern states of Michoacán, Oaxaca and Guerrero. The mining and working of metals probably came to Mesoamerican cultures from the south. Metal working was principally in gold, silver, tin and lead, with some copper work known in what is now Michoacán. Gold was generally obtained in powder or pellet form in rivers and streams from
What Is History? that events could not have happened differently unless there was a different cause. He called “these so called accounts in history represent a sequence of cause and effect interrupting and so to speak clashing with the Sequence of which the historian is primarily concerned to investigate.” He feels that the main job of a historian is to investigate the reasons/causes as to why events occurred and not to create the events or justify them. He was not a fan of "what if" history and he found it pointless because it did not happen. Carr saw accidents in history as impossible