Hauksbee generator. 18th-century diagram of apparatus used in static electricity experiments. The glass containers were rotated by turning the handle at center left. Static was generated by holding a hand against the sphere as it rotated, causing an electric discharge glow in the partial vacuum within the glass containers. This engraving is panel 7 from the second edition (1719) of 'Physico-Mechanical Experiments on Various Subjects' by the English scientist and Royal Society demonstrator Francis Hauksbee (1666-1713). This work was originally published in 1709, and included his work on air pumps and static electricity machines.