Communigraph

Known as the Ashkir-Jobson Communigraph it consists of a small table with a free moving pendulum underneath. The pendulum may then make contact with some small metal plates that represent the alphabet. The contact closes a circuit and makes a corresponding letter appear illuminated upon the table.

No medium is necessary for this instrument to work. A circle is formed around the table. The pendulum starts swinging on it's own accord.