Professor Pupin, who had been a member of the faculty of Columbia University since 1888, solved this problem in his quiet laboratory and, by doing so, won the greatest prize in modern telephone art.

His researches resulted in the famous "Pupin coil" by the expedient now known as "loading." When the scientists attempt to explain this invention, they have to use all kinds of mathematical formulas and curves and, in fact, they usually get to quarreling among themselves over the points involved.

What Professor Pupin has apparently done is to free the wire from those miscellaneous disturbances known as "induction." This Pupin invention involved another improvement unsuspected by the inventor, which shows us the telephone in all its mystery and beauty and even its sublimity.

Soon after the Pupin coil was introduced, it was discovered that, by crossing the wires of two circuits at regular intervals, another unexplainable circuit was induced.

Because this third circuit travels apparently without wires, in some manner which the scientists have not yet discovered, it is appropriately known as the phantom circuit.