This model of an electrostatic induction generator, very much in vogue for electromedical purposes towards the end of the nineteenth century, is based on the principles of electrophorus and duplicator function.

On its outer side, the fixed disk carries the inductors, two strips of tinfoil glued in the middle of two, broad paper shields placed diametrically, one beside the other.

The mobile disk carries the Toepler-Voss self-excitation system consisting of six metallic buttons, each surrounded by a ring of tinfoil, placed equidistantly in a circle.

The combs are in contact with the inner shields of two Leiden jars, and with the arms of the spark-gap, two brass bars equipped with spherules and insulation handles, into which the sparks are released.

The outer shields of the Leiden jars rest on two brass disks electrically connected by a metallic wire, which passes along the base.

A second pair of collection combs, facing the mobile disk, each with eight points and a central metal brush that rubs against the buttons, comprises the so-called “diametrical conductor”.

The “diametrical conductor” is inclined at 45° with respect to the horizontal diameter and allowed for the polarity of the linings to be maintained unaltered, especially when the exciting dynamos moved farther away than their normal explosive distance.

In this manner the machine is able to produce sparks, at times very long ones, especially if the poles of the spark-gap are in contact with the internal shields of the two Leiden jars.

This machine built in an oak-and-glass cabinet is a Toepler-Holtz generator made by the Betz company of Chicago (ca.

The pictured generator is one of the larger types and is made up of 24 glass plates, 6 sets of four each, which were rotated to produce current for therapy.

August and Maximilian Toepler started research in the field of gas discharge physics at the Dresden University of Technology.

With the application of the “streak method” Toepler succeeded as the first scientist in making acoustic waves in the air visible.

Toepler was the first to modify the principle for real time observation of liquid or gaseous flow and sound waves, where it continues to be widely used.