ATTENTION, this experiment must not be copied, wrong execution is lethal!
This experiment is similar to the experiment
human as conductor .
In this case a Geissler tube is only brought into the proximity of the tesla coil. Geissler tubes (see tube collection: Geissler tube ) need high voltage (1-4 kV) in order to ignite. In this case the electrodes as well as the gas of the Geissler tube represent a capacity in connection with the surface of the tesla coil. Moreover the human body is a capacity in connection to the earth. For alternating current the electric circuit is closed by this capacities.
See Teslacoil 16 in action to find a video.