This Violet Ray machine was a medical tool used in the early 20th century that ran small amounts of electrical current throughout the body. The current ran through glass tubes that glowed purple. Nikola Tesla invented this machine in the 19th century and introduced it at the 1893 World’s Columbian Exposition. These machines were said to cure anything from muscle pains to headaches, hair treatment to skin diseases. While some people say that this machine has little medicinal effect others believed that it is very therapeutic and does help.