The earliest methods of producing static electricity involved little more than rubbing two objects, such as amber and a person’s hand, together. The ancients found the phenomenon mystifying and pondered its nature, but never studied it in what we would today consider a truly scientific manner. The development of more complex approaches of inquiry accompanied the rise of experimentalism; in order to adequately study static electricity, scientists first needed to produce sizable amounts of it. Experimentalists also benefited from the consistency new instruments often offered, since the ability to reproduce results is key to good science.
In the mid seventeenth century, Otto von Guericke of Germany invented one of the first devices capable of generating electricity for research. Basically it consisted of a ball of sulfur mounted in a sort of wooden cradle that he manually rotated against another object to produce a charge. This electrostatic machine evolved into increasingly improved instruments in the hands of later scientists. In the early 1700s, an Englishman named Francis Hauksbee designed his own electrostatic generator, a feat stemming from his studies of mercury.
The son of a draper in Colchester, England, Hauksbee had apprenticed in a trade, as was typical of his class. He eventually ran his own shop, but in his spare time enjoyed studying science and carrying out experiments. Some of Hauksbee’s most notable experiments focused on the absence of sound in a vacuum, capillary action and electroluminescence. His interest in the latter was inspired by the work of Frenchman Jean Picard, who discovered that shaking a barometer containing mercury resulted in a glow. When news of Picard’s work reached London, Hauksbee reproduced the mercurial glow in a bell jar he evacuated with a vacuum pump of his own invention. A 1703 demonstration of the effect before the Royal Society of London caught its members’ attention and, at the urging of Sir Isaac Newton, they invited him to join their ranks. The scientific group employed Hauksbee as an experimenter from around 1705 until his death.
A few years after his first experiments with electroluminescence, Hauksbee decided to see what would happen if he removed mercury from the equation. First, he replaced the substance with other materials, then decided to leave the evacuated glass globe (which by that time had replaced the bell jar of his earlier studies) completely empty. He placed the globe on an axle attached to a large wheel. Spinning the wheel caused the globe to rotate. When Hauksbee rotated the globe very quickly against his hand in a dark room, suddenly there was light!
The light Hauksbee observed reportedly was bright enough to read by. Although he apparently had some interest in developing a lamp from this new source of light, he never did. Many years later, however, mercury lamps would come into use.
Hauksbee provided a detailed account of his device — an improved form of the electrostatic generator — in Physico-Mechanical Experiments on Various Subjects, published in 1709. His work paved the way for the construction of even better electrostatic generators capable of generating larger and larger voltages.