In 1791, Joseph Weber, a physics professor from Dillingen, described what he called an electricity doubler. This device consists of three cardboard discs covered with silver foil. The top and bottom of the discs (but not the sides) are coated with a layer of lacquer and thus insulated. The top disc has an insulating handle made of sealing wax attached to the centre of the top, while the middle disc has a corresponding handle attached to the side. To begin with, the bottom plate is electrically charged. Through a particular and fairly complex procedure in which the plates were placed on top of each other, grounded, separated again, recombined and grounded again, the original charge could be doubled (even several times), thus making extremely small amounts of electricity available for investigation.