A violet ray is an antique medical appliance used during the early 20th century to discharge in electrotherapy. Their construction usually featured a disruptive discharge coil with an interrupter to apply a high voltage, high frequency, low current to the human body for therapeutic purposes.Brain Fog - Use Applicator No. I over forehead and eyes. Also treat the back of head and neck with strong current in direct contact with the skin. Treat the spine and hold the electrode in the hand. Ozone inhalations for about four minutes are also of importance.Catarrh, Nasal - In this condition the Nasal Tube is used within the nose with a mild current within the nasal passage, two to five minutes on each side, followed by an application with the Surface Electrode externally over the area of the nose. Use Ozone Generator. A violet ray is an antique medical appliance used during the early 20th century to discharge in electrotherapy. Their construction usually featured a disruptive discharge coil with an interrupter to apply a high voltage, high frequency, low current to the human body for therapeutic purposes. Their basic construction was invented prior to 1900 by Nikola Tesla, who introduced his first prototypes at the World's Columbian Exposition in 1893. Most of the antique violet rays in the US were produced before the Depression era, and some of the larger US manufacturers of violet rays were Renulife, Fitzgerald, and Fisher. Companies who manufactured violet ray devices made many other types of electrical appliances as well, e.g. Star Electric, which also manufactured stock ticker machines. Many of the companies who were able to continue manufacturing violet rays after the Depression stopped making them due to World War II, when they began manufacturing radio coils and other electrical components for the war instead.