Earlier, when David was writing Psalms; before he enchants man with his voice and songs and commands him that craftsmanship is a collection of techniques and secrets, periods of history have been characterized by the tools used by humans: the Stone Age, the Metal Age: Copper, Bronze, and Iron. Later, in the 5th century BC, Herodotus wrote about a substance called Alum, aluminum, and further experience has shown that the inherent properties of this metal are effective in advancing industry and in the service of art.
