Toy

A small black box rested on a stand. From its top projected a metal rod approximately twelve inches high; from its side projected a horizontal metal ring. Before the box stood a thin, blond Russian, Professor Leo Theremin of State Physical Institute of Leningrad. He placed his right hand near the upright rod; a musical note streamed from the box. He wiggled his right fingers; chords and phrases danced from the box. He moved his left hand towards the horizontal ring; the music roared deeply. He removed his left hand; the music whispered forth.

This was veritable legerdemain and prestidigitation, cried journalists in Berlin and Paris, where Professor Theremin demonstrated his box early last month. And in Manhattan last week where he demonstrated again, newspapermen continued the exclamations.

Inside the box were electro-magnetic fields, actuated (through radio vacuum tubes) by an electric current that alternated at stupendously rapid frequencies. The alternations, as is the case with radio broadcasting waves, were too rapid for human ears to hear. But Professor Theremin, as anyone can do with a heterodyne radio receiving set, put one series of his electro-magnet waves against another series and thereby deadened a sufficient number of the millions of waves speeding silently through the box each second to leave few enough oscillations for audibility. (The highest number of waves that the ordinary human ear can hear is close to 30,000 a second.) And just as a radio amateur can make a cheap receiving set squeal by moving his hand about the unprotected parts and thus altering the electrical tension of the whole set, just so Professor Theremin altered the electro tension of the electro-magnet fields within his box. The precision with which he built his contrivance permitted him to extract, not amateur squeals, but harmonious musical sounds. (Gestures with his left hand about the horizontal ring were the equivalent of turning the amplifying knob of a receiving set to & fro.)

Professor Theremin's apparatus can be played as a musical instrument. Nonetheless it is yet a scientific toy, just as another device, interpreting sounds as light waves and shown to the curious throughout the U. S. a few years ago, was a toy. And as the inventors of that sound-color machine toured the U. S. exposition halls, so Professor Theremin's associates plan to take him and his box on tour.