Nelson?s Secret Invention. Columbus: Nelson Enterprises, 1950s. A secret two-way communication device consisting of a pocket radio transmitter and receiver, meant for use by mind reading acts to facilitate the secret communication between the medium on stage and the mentalist in the audience. Outfit consists of aluminum receiver and transmitter, leg or arm straps, antennae, earpiece, microphone, and other accessories. With later typewritten instructions. Includes tools for repair. Housed in a custom carrying case. Rare. One of the most expensive articles offered by Nelson, the Secret Invention was a James Bond-type sub rosa device. Now obsolete, at the time these were offered to the fraternity, the technology incorporated into these tiny machines seemed space-age to the unsuspecting public, and made miracles possible. It is widely believed that they were constructed for Nelson by Bill Dodson of Louisville, KY, who was well-known as a maker of electromagnetic devices for crooked gamblers.