A 'Helios' set medical instruments for ultraviolet light therapy in case, Germany, 1920's.

The suitcase with electricity converter with regulator switch, including various glass tubes with noble gas and together with a brush with copper hairs. Note: This set was used for various medical treatments amongst which skin diseases, making use of frequention waves and neon light. A handle with copper clip could hold various glass tubes, filled with noble gas. By pressing the tubes against the skin altering streams between gas and skin were created. The gas was then ionized, leading to sparks between the gas and skin. This resulted in a blue glow, ticking noise and stinging sensation. Sometimes copper brushes were used to enhance the beforementioned sensations. The principle was invented by Tesla who presented it at the world fair of Chicago in 1893. Estimate: € 100 - € 150.