The wand of a violet ray machine, a quack home medical appliance sold from the 1920s to the 1950s, photographed by its own glow. It consists of a high voltage Tesla coil that applies 30 - 80 kV to an electrode sealed inside a glass tube filled with argon at reduced pressure. The tube produces this dramatic glow while operating. It was applied to various parts of the body and was said to cure everything from carbuncles to lumbago. This German unit had no identifying text on it except the name Hochfrequenz 309