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Frictional Electrostatic Generators
A1.1 globe The globe generator was invented by Francis Hauksbee the Elder. (He was succeeded by his nephew, Francis Hauksbee the Younger, and when they worked they were not especially careful about the distinction. This confusion has plagued generations of scholars trying to determine which Francis did what.) We don't have any of Hauksbee's generators (as far as I know, nobody does) but at least we have the book he wrote about them. While Hauksbee is often considered the creator of the electrostatic generator, some consider Otto von Guericke to have that honor. He invented a vacuum pump which led to the famous Magdeburg demonstration of teams of horses trying - and failing - to separate two half-globes held together with a vacuum between them. He also created a sulfur globe with which he demonstrated a number of electrical effects. His globe, however, seems to have died without issue. The globe is a natural shape for blown glass, so many of the early static generators were globes. One of our globe generators from the later part of the eighteenth century was made by the famous team of Nairne and Blunt. Another is by an unknown maker, but especially interesting because it is made of copal (a younger form of amber). Cylinders Glassblowers can easily make globes with one neck - it's not that different from blowing a vase - and they were used in the early days of electrical study. But a globe, held only at one end and spun against a friction cushion, is in a perilous situation. The neck could easily snap. Since the earliest friction cushion used to rub the glass globes was the human hand, it easily conformed to the shape of the globe; but the possibility of broken glass in proximity to the hand made people nervous. In 1743-44, Andreas Gordon and Johann Winkler began using glass cylinders in their electrostatic machines. (Nobody is really sure who did it first.) A cylinder is as easy to blow as a bottle - just blow the glass bubble inside a mould. With little extra work, it can be made with a neck on each end. Supported on both ends - often with a solid axle completely through the cylinder - it is much sturdier than the usual globe machine. By the end of the century, famous makers such as George Adams and Thomas Blunt were turning out handsome and refined cylinder machines. Plates The invention of the plate electrostatic generator is often attributed to Jesse Ramsden of London, sometimes to Ingenhausz of Vienna, and to a multitude of others. All that is known for sure is that plate generators began appearing in many places in the later 1750s. They were safer than globe or cylinder generators, because the plate could not explode the way a sealed vessel could if the friction of electrical excitation overheated the air inside. Since the plates were fastened only at the center, while cylinders could be fastened at both necks, plate machines required more care in their manufacture. The most celebrated maker of plate generators was probably John Cuthbertson, who began his career in England but made his most notable machines in Holland.
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Frictional
Electrostatic Generators can be classified in quite a few ways. At
The Bakken, we sort them out according to the shape of the object being
rubbed, with a special category for amber, the "ur-electric" that
gave its name to the entire field. 
Both
plate and cylinder generators continued to be sold and used throughout
the nineteenth century and into the Twentieth. When the Bakken needed
several electrostatic generators for a workshop, we found we could
not afford modern generators. (The generators in our collection were
not used: their historic value is much more important than their practical
value.) And so we turned to an old design, reworking the plate generator
of the nineteenth century into a generator for the twentieth. Now in
the twenty-first century, we are still using them in our classes. One
can be seen to the right, raising hair electrostatically. A modern
Van de Graff generator sits below the table, unused - the plate generator
is more reliable, and gentler.