Zinc is a familiar element, used to galvanise iron to prevent rusting. But unlike iron, its widespread use is a relatively modern phenomenon because of the difficulty in extracting it from its ore. Zinc has a low boiling point and so at the temperatures used to smelt iron, zinc escapes as a gas. The technology to obtain metallic zinc was first developed in India where it was produced in quantity from the twelfth century. By the sixteenth century it was also produced in China and was exported from Asia to Europe. It was not until the mid-eighteenth century that commercial processes to extract zinc were developed in Europe.
This design uses an alchemical symbol for zinc (probably the last alchemical symbol I shall use), found in Pierre Joseph Macquer’s Table of Chemical Characters published in 1777.
