The two dischargers below are unmarked, and are at Denison University (left) and Kenyon College (right).
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If, on the other hand, the experimenter wants to observe the effect of an electrical discharge through a body, the universal discharger is used; five examples are shown below. This is often called Henley's discharger, named, I think, after William Henley, who developed Henley's electrometer in 1770. The two electrodes are connected to the electrostatic machine, and the sample is placed atop the table. Sometimes a slab of ivory is let into the table top to serve as an insulator. The 1856 Benjamin Pike catalogue suggests that the apparatus might be used for demonstrations of the oxidation of metallic leaves between slips of card or of glass, splitting small pieces of oak and firing gunpowder. An example of the latter demonstration is shown on the bottom of this page.
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| At the right is an example of Lane's (or Riess') discharger
in the collection at Washington and Jefferson College.
This device, which is not set up properly in the picture, is used to deliver constant amounts of charge from a Leiden jar. Thus, a fully charged jar can deliver a whole series of charges of equal size to a system. The picture below, from Linnæus Cumming, "Electricity
Treated Experimentally" (Rivingtons, London, 1886), pg 146, shows how the
discharger is used to supply constant amounts of charge from a battery
of Leiden jars to a universal discharger.
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