The ‘Radio Organ of a Trillion Tones’ (1931), The ‘Polytone Organ’ (1934) . Arnold Lesti, Leo Tiedemann & Fredrick Minturn Sammis. USA, 1934


The Trillion Tone Organ
Lesti and Tiedemann’s  Trillion Tone Organ of 1931

Radio Organ of a Trillion Tones (1931)

The “Radio Organ of a Trillion Tones” was created and developed by Arnold Lesti and F. Sammis in the USA during 1931. The Radio Organ used a similar photo-electrical technique as the Celluphone, Superpiano and other variants. However the The Radio Organ generated a much more complex sound by projecting the light beam through two sets of glass disks – a ‘Pitch disk’ generating a pitched fundamental plus it’s ascending harmonics and a Timbre disk modifying the tone using a drawn representation of the sound wave of a real instrument (horn ,violin, clarinet, oboe and a human voice).  The principle was improved in the next version called the “Polytone”.
The "Radio Organ of a Trillion Tones" (1931)
The “Radio Organ of a Trillion Tones” (1931)
Diagram showing the tone and pitch disks
Diagram showing the tone and pitch disks

The Polytone Organ (1934)

A. Lesti and F. Sammis’s development of the Radio Organ of a Trillion Tones was christened the ‘The Polytone Organ’, this instrument was a three keyboard manual organ using the same sound production system as the ‘Radio Organ’ – rotating photo-electrical tone-wheel sound generation. The instrument was completed in 1934 and was one of the first multi-timbral instruments.
polytone organ. Electronics USA Feb 1934 p39


The ‘Hammond Organ’. Laurens Hammond, USA, 1935

The original Hammond Organ was Designed and built by the ex-watchmaker Laurens Hammond and  John M Hanert in April 1935. Hammond set up his ‘Hammond Organ Company’ in Evanston, Illinois to produce electronic organs for the ‘leisure market’ and in doing so created one of the most popular and enduring electronic instruments ever built.
Hammond’s machine was designed using technology that relates directly to Cahill’s ‘Telharmonium’ of 1900, but, on a much smaller scale. The Hammond organ generated sounds in the same way as the Telharmonium, the tone wheel – The tone generator assembly consisted of an AC synchronous motor connected to a gear train which drove a series of tone wheels, each of which rotated adjacent to a magnet and coil assembly. The number of bumps on each wheel in combination with the rotational speed determined the pitch produced by a particular tone wheel assembly. The pitches approximate even-tempered tuning.
This method of creating tones was maintained  until the mid 1960’s when transistors replaced tone wheels
The Hammond had a unique drawbar system of additive timbre synthesis (again a development of the Telharmonium) and stable intonation – a perennial problem with electronic instruments of the time. A note on the organ consisted of the fundamental and a number of harmonics, or multiples of that frequency. In the Hammond organ, the fundamental and up to eight harmonics were available and were controlled by means of drawbars and preset keys or buttons.A Hammond console organ included two 61-key manuals; the lower, or Great, and upper, or Swell, and a pedal board consisting of 25 keys. The concert models had a 32-key pedalboard. Hammond also patented an electromechanical reverb device using the helical torsion of a coiled spring, widely copied in later electronic instruments.
As well as being a successful home entertainment instrument, The Hammond Organ became popular with Jazz, Blues and Rock musicians up until the late 1970’s and was also used by ‘serious’ musicians such as Karlheinz Stockhausen in “Mikrophonie II”

Hammond patent documents

The ‘Sonothèque’. Léonce Lavallée, France. 1936

Léonce Lavallée’s ‘Sonothèque’ or “sound library” was a  “coded performance electronic instrument using photo-electric translation of engraved grooves”. The instrument was capable of reading music and sounds encoded graphically with conductive ink sensed by a set of electrically charged brushes – a graphic encoding method that was used a decade later by John hanert with the Hanert Electric Orchestra .

The instrument was patented (FR806076) in 1936 as ‘Dispositif pour la reproduction sonore d’une partition de musique avec utilisation d’enregistrement de sons élémentaires’ or ‘Device for the sound reproduction of a musical score using the recording of elementary sounds’ and, according to Le Caine was demonstrated in Paris in 1929:

“The first public demonstration of “synthetic music” made by electronic devices was at the Paris Exposition of 1929, where a roll-operated device consisting of four monophonic electronic oscillators was shown with great success. Following the basic patent covering this device,*” there are other similar French patents. In one of these,“ a number of different devices are described, that allow the composer or arranger to draw by hand the sound envelope. In one form of the invention, the arranger engraves a groove in a suitable support which varies either in depth or in position at right angles to the time axis. When the music is reproduced, a needle following the groove operates an optical wedge to control the light passing through a sound-on-film recording to a photocell. In another form of the invention, the arranger draws by hand in conductive ink, a mark of varying width or position which is read by a series of brushes to set up the sound envelope. As a sound source, the inventor uses a “sound library” (sonothéque) consisting of suitable supports on which are recorded by any known method the various notes of the various instruments, in addition to vocal sounds and other noises. As an alternative, synthesis from pure tones is mentioned.”


Thomas LaMar Rhea. ‘The Evolution of Electronic Musical Instruments in the United States’ 1972

Hugh Le Caine, ‘Electronic Music’, Proceedings of the IRE, 44 (1956), pp. 457–78.


The ‘Hellertion’ and The ‘Heliophon’. Bruno Hellberger & Peter Lertes, Germany, 1929-1936

The Hellertion
The Hellertion

The Hellertion (1929)

The Hellertion, christened after the combination of the inventor’s names, was a monophonic vacuum tube instrument developed collaboratively by Peter Lertes, an electrical engineer in Leipzig and Bruno Helberger from Frankfurt, a well-known pianist of his time. Several variants of the instrument were constructed with the assistance of Schneider-Opel in Frankfurt, Germany the last of which was known as the Heliophon.
Bruno Hellberger at the Hellertion
Bruno Hellberger at the Hellertion attached to a grand piano
The Hellertion was the first electronic instruments to use a fingerboard/continuous controller instead of a keyboard manual and was much copied in other later instrument designs such as the Trautonium and the Sonar. The fingerboard was a flat metal resistance strip covered in leather which when pressed completed a circuit. Depending on where the strip is pressed, a different resistance in the circuit is created altering the voltage sent to the oscillator and thereby producing different pitches. The force of the pressure controlled the volume of the output signal. The fingerboard was marked to help the performer find the correct pitch on the strip and had a range of approximately five octaves.
The wire manual of the Hellertion with an added key reference guide. (image; Radio Wien. 1932)
(image; Radio Wien. 1932)
The original instrument had just one fingerboard strip which was gradually increased to four and then on the later models, six aligned in parallel horizontally at the height of a piano keyboard. The four and six strip models allowed four and six voice polyphony when the strip could be played simultaneously with fingers and thumbs. The Hellertion was occasionally used in concerts as a piano addition, the melody being played with one hand on the Hellertion and the accompaniment being played with the other hand on the piano. A version of the Hellertion was produced in 1931 microtonally tuned to 10 divisions of an octave.
Diagram showing the sliding control of the Hellertion.
Diagram showing the sliding control of an early model of the Hellertion.
Peter Lertes’ book on Electronic Music “Elektrische Musik. Eine gemeinverständliche Darstellung ihrer Grundlagen, des heutigen Standes der Technik und ihrer Zukunftsmöglichkeiten, etc” Theodor-Steinkopff-Verlag 1933

Patent documents of the Hellertion


The Helliophon (1936)

Bruno Helberger's 'Heliophon'
Bruno Helberger’s ‘Heliophon’
development of the Hellertion by Bruno Hellberger. The first version of the Heliophon was completed in Berlin, 1936 but destroyed during WW2. Hellberger continued the development after the war and built a second model in 1947 in Vienna, Austria and continued the development of the Heliophon until his death in Vienna in 1951 (subsequent development was taken over by Wolfgang Wehrmann). The sound of Heliophon was produced, as with the Hellertion, by heterodyning vacuum tube oscillators but with the Heliophon the sound was controlled by two 58 note pressure sensitive keyboard manuals instead of a series of fingerboard strips. Each keyboard had the ability to be split into three different pitches and timbres simultaneously, the output volume being controlled by foot pedals with a knee lever to add vibrato. Each keyboard had a Hellertion style fingerboard to add glissando and timbre variations. The Heliophon was used by Hellberger throughout the 1940s and ’50s for theatrical and musical productions, the instrument was said not only to be capable of producing realistic imitations of orchestral instruments but able to imitate human vocal sounds.
Helberger’s patent documents for the Heliophon
Bruno Helberger and the Hellertion as a Grand Piano attachment.
Bruno Helberger and the Hellertion as a Grand Piano attachment.


A survey of ‘modern’ electronic instruments was published by Peter Lertes in 1933: “Elektrische Musik:ein gemeinverständliche Darstellung ihrer Grundlagen, des heutigen Standes der Technik und ihre Zukunftsmöglickkeiten” (Dresden & Leipzig, 1933)J.Marx:”Heliophon, ein neues Musikinstrument”, Ömz,ii(1947),314

 “Das Hellertion, ein neues electrisches Musikinstrument,” Funkbastler, July 3, (1931).

“The Invisible Weapon : Telecommunications and International Politics, 1851 …”
By Daniel R. Headrick Professor of History Roosevelt University

‘Electronic and Experimental Music: Pioneers in Technology and Composition’
By Thomas B. Holmes, Thom Holmes

Peter Donhauser: “Elektrische Klangmaschinen”, Böhlau Verlag, 360 S., ISBN 978-3-205-77593-5

‘Radio Wien’ 1932 ‘Elektrische Musik’

The ‘Welte Licht-Ton-Orgel’ or ‘Phototone Organ’ . Edwin Welte, Germany, 1936

The "Welte Licht-Ton Orgel" (Light-Tone organ) (1936)
The “Welte Licht-Ton Orgel” (Light-Tone organ) (1936)
The Welte Light-Tone was one of the last instruments designed by Edwin Welte (1876-1958) of the famous Welte-Mignon mechanical instrument manufacturers. Welte had become fascinated with the possibility of using optical disks since 1925 and produced a number of prototypes using clay optical disks before completing the glass-disk based production version of the Lichttonorgel. The sounds of the Lichttonorgel consisted of photographically drawn ‘recordings’ of different models of famous organs of the day but in theory could play back any recording of any instrument.
The organ premiered on November 6th 1936 at the Berlin philharmonic played by the  virtuoso German organist Kurt Grosse and received enthusiastic review from the National Socialist newspaper the Völkische Beobachter (9. November 1936) “ A unique miracle, perfection in the entire realm of concert instruments” and speculated that it would be a perfect instrument for National Socialist rallies – on the strength of  this endorsment, The German Telefunken comany negotiated a production deal. Any potential the instrument had was destroyed by the Nazi’s discovery of Welte’s marriage to a German Jew and Telefunken’s immediate withdrawal of their contract. After the war Welte continued to try and make a commercial success of the instrument but eventually foundered due to the complexity of the photo-electric system and  from increasing competition from cheaper and more efficient instruments such as the Hammond Organ. Welte. Only three  production models of the Lichtonorgel were completed.
A detail of one of the the Light Tone Organ's glass disks.
A detail of one of the the Light Tone Organ’s glass disks.
The instruments sound generation unit consisted of 12 glass disks which were printed with 18 different looped waveforms in concentric rings. The glass ‘tone wheel’ disks were rotated over a series of photoelectric cells, filtering a light beam that controlled the sound timbre and pitch. The resulting combinations of tones gave 3 different timbres for all the octave registers of each note on the keyboard. The German arm of the Welte-Mignon company in Frieburg was completely destroyed in 1944 by allied bombing and all of the companies closely kept secret designs were lost forever.
Light beam disk of the Licht-ton Orgel
Light beam disk of the Licht-ton Orgel
Light beam disk of the Licht-ton Orgel
Light beam disk of the Licht-ton Orgel
Welte's Licht-Ton-Orgel
Welte’s Licht-Ton-Orgel


Edwin Welte.  March 28 1876 in Freiburg im Breisgau , † January 4 1958 in Freiburg im Breisgau
Edwin Welte. March 28 1876 in Freiburg im Breisgau , † January 4 1958 in Freiburg im Breisgau

Biographical Information

Edwin Welte (1876-1958) and his brother-in-law, Karl Bockish, developed the Welte-Mignon reproducing piano in 1904 for M. Welte & Soehne of Freiburg, Germany. Music roll recording commenced in 1905.  The recording piano and the reproducing system were entirely new inventions which astounded the musicians and fans in Europe.  In 1906 (?) he established “The Welte Artistic Player Piano Company” in a showroom in New York and soon was producing pianos and music rolls for American customers.

The Welte Company

The Welte Company was a German organ firm which was first established in 1832 at Vörenbach (Black-Forest) by automata manufacturer Michael Welte (1807-1880). In c1865 he moved to Freiburg/Breisgau and the firm was registered there as M. Welte & Söhne. During the remainder of the 19th century the Welte firm expanded considerably and became particularly noted for their orchestrions. Welte’s “Cabinet player”, a reproducing piano without keyboard which bore the Mignon label, was first patented in 1904 while the firm was under the direction of Edwin Welte (1876-1958, grandson of the founder). The prototype was exhibited during late 1904 in Leipzig and became commercially available from early 1905. The Vorsetzer came on the market in 1908.
Mignon was integrated into their upright pianos in 1909, and into their grand pianos from 1913. In 1908 the technology was adapted and applied to the Welte “Philharmonic Autograph Organ”. This was the forerunner of the “Welte-Philharmonie Organ” which was first publicly displayed at the Turin Exhibition of 1911. The firm then went on to successfully market player organs, cinema organs and, later, when their market contracted during the 1930s, church organs. They concurrently produced rolls of performances by the greatest organists of the day and sold them with considerable commercial success. From 1865-1917 they also ran a branch in New York (M. Welte & Sons) under Emil Welte (1841-1923, eldest son of the founder), but it was closed during World War I as an “alien enterprise”.
Welte factory in Freiburg, Germany
Welte factory in Freiburg, Germany
Welte’s instruments became status symbols and the epitome of entertainment in their day. They were installed in stately houses, palaces, schools, department stores (Harrods in London had one), yachts, ships (one was manufactured just too late to be aboard the Titanic) and even apparently a “house of pleasure” (the Atlantic Garden orchestrion). Around the world they were dispersed throughout Europe, USA, with their market is known to have extended much further – to Istanbul, Russia, China and Sumatra for example. The top of Welte’s Orchestrion/player-organ range was the “Welte-Philharmonie”. Very few of the full- sized model were ever manufactured. From about 1926 Welte began to be threatened by a rapidly growing radio and recording industry. Business declined so much that, in 1932 they narrowly escaped bankruptcy. At about this time they were also involved in a collaboration with the Telefunken Company which was terminated because Edwin Welte’s first wife, Betty Dreyfuss, was Jewish.
This stalled collaboration involved the development of electronic organs. Using (analog) sampling and photo-cells, truly prophetic developments at that time, had Welte been successful they might well have eliminated the Hammond organ from the pages of history. It was World War II which finally precipitated the total demise of the firm. The Freiburg premises – all stock, instruments and historical documents – were effectively annihilated by British bombing in November 1944. The bombed out factory was something of a landmark by the Freiburg railway station for at least decade until the mid-1950s.  (from: Museum of Music Automatons, Seewen)


Museum of Music Automatons Seewen (

Michael Gerhard Kaufmann : Organ and National Socialism. Kleinblittersdorf 1997. ISBN 3-920670-36-1 .

The Organ: An Encyclopedia.  edited by Douglas Earl Bush, Richard Kassel

NS-Kulturgemeinde (Germany)Nationalsozialistische Deutsche Arbeiter-Partei. Amt Musik. M.Hesse, 1936


The ‘Melodium’. Harald Bode, Germany, 1938

The "Melodium" (1938)
The “Melodium” (1938)
Bode’s second instrument, previewed in 1938 was a monophonic touch sensitive keyboard instrument, the ‘Melodium’, developed with the assistance of Oskar Vierling, inventor of the ‘Grosstonorgel’. The instrument was used extensively for film music and ‘light music’ during the 1940’s.
Bode had designed oscillators with good pitch stability given the technology of the time, but he realized that a monophonic instrument would present far fewer tuning problems than his radical Warbo Organ. Like all good designers, Bode understood the necessity for providing increased nuance capability in a solo instrument; hence, touch sensitivity. The Melodium had a 49-note keyboard (low-note priority). But unlike traditional keyboards, each key had a fulcrum, or pivot point, not at the rear of the key, but at its midpoint. Each key was an individual little teeter-totter; when the performer depressed any key, he or she could seesaw a long aluminium rail located at the rear of all keys up and down. This rail made contact with a strip of felt soaked in glycerine — a so-called “liquid potentiometer.” Depression of the felt altered the electrical resistance between two electrodes, providing loudness control. This was a direct keying system that should not be confused with modern force-sensitive keyboards found on certain synthesizers. On the Melodium, the actual onset of sound was begun like it is on most acoustic instruments: as a function of the performer’s continuously variable mechanical effort. This is unlike most of today’s synthesizers; they have electronic envelope generators with fixed time constants for attack and release. Even when a synthesizer is force-sensitive, this sensitivity is usually in conjunction with the unvarying envelope generator attack and release. (Thomas L. Rhea. Contemporary Keyboard magazine (January 1980, p. 68) )

The articulation on the Melodium has been likened to that of Franklin’s Glass Harmonica, an instrument having rotating glass disks that are played with moistened fingers. This characteristic singing (slow) attack, and the tone colours produced by formant filters borrowed from the earlier four-note organ, made the Melodium an expressive and colourful instrument that found public acceptance. Bode says:

… it was a very responsive instrument to the response of the artist, although it didn’t have these automatic — or maybe because it didn’t have these automatic [envelope] — controls.” Harald Bode

Due to its unorthodox design, the Melodium was not suitable for mass production; it found public acceptance through its rental for film scores, stage plays and on German radio. It enjoyed a considerable vogue with German film score composers. The brief career of the Melodium ended in 1941 due to the war; eventually Bode had to cannibalize the instrument due to the scarcity of electronic components.

The "Melodium" (1938)
The “Melodium” (1938)

Biographical notes

Harald Bode; October 19, 1909 Hamburg Germany – January 15, 1987 New York USA.
Harald Bode; October 19, 1909 Hamburg Germany – January 15, 1987 New York USA.

Bode Studied  mathematics, physics and natural philosophy at Hamburg University, graduating in 1934. In 1937, with funding support provided by the composer and band-leader, Christian Warnke, Bode produced his first instrument the ‘Warbo-Formant Orgel’ (‘Warbo’ being a combination of the names Warnke and Bode). Bode moved to Berlin in 1938 to complete a postgraduate course at the Heinrich Hertz Institute where he collaborated with Oskar Vierling and Fekko von Ompteda. During this period Bode developed the ‘Melodium’ ;  a unique monophonic touch-sensitive, multi-timbral instrument used extensively in film scores of the period.

When WWII started in 1939 Bode worked on military submarine sound and wireless communication projects “…We had the only choice in Germany, to go to military service or do work for the government. I praise myself lucky, that I was able to go to the electronic industry” and moved to the  small village Neubeuern in southern Germany, where in 1947 Bode built the first European post-war electronic instrument, the ‘Melochord’. In 1949 Bode joined the AWB company where he created the  ‘Polychord’ a simpler, polyphonic version of the ‘Melochord’ which was followed by the ‘Polychord III’ in 1951 and the  ‘Bode Organ’, a commercial organ which became the prototype for the famous Estey Electronic Organ. After leaving AWB, Bode’s designs included the ‘Tuttivox’, a miniature electronic organ and collaborated on a version of Georges Jenny’s ‘Clavioline’, both big sellers throughout Europe.

In 1954 Bode moved to the USA, settling in Brattleboro, Vermont where he lead the development team (and later, Vice President)  at the Estey Organ Corporation. In 1958, while still working at Estey, Bode set up the Bode Electronics Company where in March 1960 he created another unique instrument; a modular synthesiser “A New Tool for the Exploration of Unknown Electronic Music Instrument Performances” known as the  ‘Audio System Synthesiser’ which Robert Moog used as the basis for his line of new Moog synthesisers.

After the Estey Organ Company foundered in 1960, Bode joined the Wurlitzer Organ Co and moved to Buffalo, New York where he was one of the first engineers to recognise the significance of transistor based technology in electronic music.  Bode’s concepts of modular and miniature self-contained transistor based machines was taken up and developed in the early 1960’s by Robert Moog and Donald Buchla amongst others. 1962 saw the beginning of a long collaboration between Bode and the composer Vladimir Ussachevski at the  Columbia Princeton Center for Electronic Music which lead to the development of innovative studio equipment designs such as the  ‘Bode Ring Modulator’ and ‘Bode Frequency Shifter’. The commercial versions of these inventions were produced  under the Bode Sound Co and under license Moog Synthesisers.

Harald Bode retired in 1974 but continued to pursue his own research. In 1977 he created the ‘Bode Vocoder’ (licensed as the ‘Moog Vocoder’). In 1981 he developed his last instrument, the ‘Bode Barberpole Phaser’.



Bode’s Melodium and Melochord by Thomas L. Rhea. Contemporary Keyboard magazine (January 1980, p. 68) 

The ‘Kaleidophon’ Jörg Mager, Germany, 1939

Jörg (Georg Adam) Eichstätt Mager born November 6, 1880 Aschaffenburg, Bavaria, Died Aschaffenburg 1939
Jörg (Georg Adam) Eichstätt Mager born November 6, 1880 Aschaffenburg, Bavaria, Died Aschaffenburg 1939

Little information survives of Jörg Mager’s last instrument the ‘Kaleidophon’ which he completed in 1939. The instrument was probably destroyed by allied bombing of Mager’s Darmstadt headquarters. The only references survives as notess “…a monophonic electronic instrument with kaleidoscopic sound mixtures following the tonal precepts of Arnold Schoenberg and Ferruccio Busoni.”

More on Jörg Mager here

The ‘Novachord’ Laurens Hammond, John Hanert & C.N.Williams. USA, 1939

The Hammond Novachord
The Hammond Novachord. Image :Dan Wilson, Hideaway Studio (

The Hammond Novachord was manufactured by the Hammond Organ Co in the USA from 1939 to 1942, designed by Laurens Hammond, John Hanert and C.N.Williams. A total of 1096 models were built.The Novachord was a polyphonic electronic organ and was Hammonds first electronic tube based instrument – a departure from his usual tone-wheel designs. The Novachord was a much more complex instrument than the Solovox Hammond’s other electronic tube-based instrument. The Novachord had 169 vacuum tubes to control and generate sound and was played on a seventy two note keyboard with a simple pressure sensitive system that allowed control over the attack and timbre of the note. The sound was produced by a series of 12 oscillators that gave a six octave range using a frequency division technique; the Novachord was one of the first electronic instruments to use this technique which was later became standard in electronic keyboard instruments.

Novachord fron panel
Novachord fron panel

The front panel of the instrument had a series of 14 switch-able rotary knobs to set the timbre, volume, ‘resonance’,bass/treble, vibrato (six modulation oscillators were used) and ‘brightness’ of the sound. A set of 3 foot operated pedals controlled sustain,and volume the third pedal allowing control of the sustain by either foot. The final signal was passed to a pre-amplifier and then to a set of internal speakers. The Novachord was able to produce a range of sounds imitating orchestral instruments such as the piano, harpsichord, stringed and woodwind instruments as well as a range of it’s own new sounds. In May 1939 ‘The Novachord Orchestra’ of Ferde Grofé performed daily at the Ford stand at the New York World Fair with four Novachords and a Hammond Organ and in Adrian Cracraft’s ‘All Electronic Orchestra’, the Novachord also featured in several film scores (Hans Eisler’s “Kammersinfonie” 1940) but seems to have fallen from favour due to the instability of it’s multiple tube oscillators and playing technique. The Novachord was discontinued in 1942. A Hammond employee comments:

“The Novachord made beautiful music if played well, but it was not well adapted either to either an organists style or a pianists style. Thus it required development of a specific style, which not many musicians were prepared to do. it also had technical problems, requiring frequency adjustments to keep it operating chiefly because the frequency dividers and electronic components before the war were not nearly as good as those available in later years. The hammond Organ Company could have revived it after the war, and could have made it better in light of available technology at the time, but sales had been disappointing ad so it was not considered a good commercial product”
The Hammond Novachord from a 1940s promotional brochure. Image :Dan Wilson, Hideaway Studio (
The Novachord in 'Popular Mechanics' magazine USA 1939
Laurens Hammond and the Novachord in ‘Popular Mechanics’ magazine USA 1939
The Novachord in 'Popular Mechanics' magazine USA 1939
The Novachord in ‘Popular Mechanics’ magazine USA 1939
Hammond Novachord in “New Horizons” 1940
A restored Novachord
Novachord Orchestra: Introduction of The Hammond Novachord at the New York World’s Fair 1939 – 1940.


F.D.Merril jr: “The Novachord”, Electronics,xii/11 (1939),16