English: Rev. Irwin Moon, a touring evangelist, in one of his "sermons from science" in 1938 shooting sparks from his fingertips. This spectacular special effect, which was also used by circus sideshow performers of the time, was accomplished by connecting a hidden Tesla coil to his body. The Tesla coil produces very high voltage, around several hundred thousand volts so it can create foot long sparks, but low current, and because it is alternating current with a high frequency (in the radio range, 100 kHz to 2 MHz) it does not cause the sensation of electric shock. The brush discharge sparks emanate from any pointed parts extending from his body, like his fingers. Although they don't cause a shock, the sparks would burn his fingers, so he uses metallic thimbles on the ends. The article says the equipment for this special effect cost $10,000.

At this time it was thought that, due to skin effect, high frequency currents traveled along the surface of a person's body and didn't penetrate to vital organs, so Tesla currents couldn't cause shock and electrocution. However today it is known that this is false and Tesla currents do penetrate the body, and stunts like this are extremely dangerous and can cause electrocution. DON'T TRY THIS.