The terpodion or uranion is a

keyboard instrument A keyboard instrument is a musical instrument played using a keyboard, a row of levers that are pressed by the fingers. The most common of these are the piano, organ, and various electronic keyboards, including synthesizers and digital piano ...

which produces

sound In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the br ...

using the same

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...

principle as the

glass armonica The glass harmonica, also known as the glass armonica, glass harmonium, bowl organ, hydrocrystalophone, or simply the armonica or harmonica (derived from , ''harmonia'', the Greek language, Greek word for harmony), is a type of musical instr ...

. Instead of rotating glass bells a wooden cylinder is rotating. This cylinder is coated with a special mixture. Examples of these instruments can be seen in museums all over Europe, including museums in Copenhagen, Leipzig, Vienna, London, Brussels, Stockholm,

Jevišovice Jevišovice () is a town in Znojmo District in the South Moravian Region of the Czech Republic. It has about 1,200 inhabitants. The historic town centre is well preserved and is protected as an urban monument zone. Geography Jevišovice is locate ...

and Frankfurt/Oder.

Manufacture history

Only 25 instruments were ever built by Christian Friedrich Ludwig Buschmann, the son of Johann David Buschmann, the inventor of this instrument. Johann David Buschmann was first a passementier, then he started repairing key instruments. By 1817 the instrument spanned a range of 5 1/2 octaves. In 1821, one such instrument arrived in London. Also in 1821, David Buschmann sold a licence for building terpodions to the instrument builder David Loescham and the cheesemonger James Allwright. Following this, only one instrument was ever built in England. In 1841, another report could be read in the London newspaper.

Technical explanation

There is a certain relationship with the glass harmonica and the clavic cylinder. The glass harmonica produces the sound by friction from touching the rotating bells with wet fingers. With the terpodion, operating the keyboard pushes a wooden or metal arm against a rotating coated cylinder of wood or other material, producing sounds by friction. For the lower notes the arms are mainly made of wood and for the higher notes they are made of metal. The arms are adjustable so the pitch of each note can be adjusted within the tuning process. The terpodion rarely requires tuning. The rotating cylinder is made from box wood (

Buxus sempervirens ''Buxus sempervirens'', the common box, European box, or boxwood, is a species of flowering plant in the genus ''Buxus'', native to western and southern Europe, northwest Africa, and southwest Asia, from southern England south to northern Morocco ...

), but the patent states it could be any material. The most important aspect of the cylinder is the coating. The exact mixture can be seen in the patent document: 2 parts

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

, 1 part mastic, 1 part

sandarac Sandarac (or sandarach) is a resin obtained from the small cypress-like tree '' Tetraclinis articulata''. The tree is native to the northwest of Africa with a notable presence in the Southern Morocco part of the Atlas Mountains. The resin exudes n ...

, 1/16 part

camphor Camphor () is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel (''Cinnamomum camphora''), a large evergreen tree found in East Asia; and in the kapu ...

. The vibrating parts are pushed by the key mechanism toward the rotating cylinder so a sort of hammer that is covered by soft rough leather, which is coated with same mixture as the cylinder. The volume of the sound is dependent on the amount of pressure applied to the keys. The lower register requires more pressure for the same amount of volume as the higher register. The instrument did not stay playable for long and had to be serviced from time to time. This may be one of the reasons why the Buschmanns looked for other ways of producing the sound, and replaced the friction sound production with free reeds on other instruments. The instrument had piano keys, and a similar look to the later

reed organ The pump organ or reed organ is a type of organ that uses free reeds to generate sound, with air passing over vibrating thin metal strips mounted in a frame. Types include the pressure-based harmonium, the suction reed organ (which employs a va ...

s. On the other hand, there were also instruments built that had both a keyboard for the friction sound and another one for the

free reed A free reed aerophone is a musical instrument that produces sound as air flows past a vibrating reed in a frame. Air pressure is typically generated by breath or with a bellows. In the Hornbostel–Sachs system, it is number 412.13 (a member of ...

sound. Buschmann was one of the first to use vacuum type reeds in his physharmonicas.

The Melodion of Dietz

The melodion was very much like the terpodion. The one invented in 1806 by Dietz in Emmerich was presented to the public by Petzhold (or Betzold) in many places in Europe. There was only one main difference; all the sound came from vibrating metal structures.

"Der Ton wird durch die Reibung metallener Stäbe ..mittelst dem mit einem elastischen Körper umringten, sich umdrehenden Cylinders hervorgebracht, welcher ..mit den Füssen des Spielers in Bewegung gehalten wird, .. Vom Melodion wurden bei weitem mehr Instrumente gebaut als vom Terpodeon. "Seine Fabrik ist bereits in solchem Flor renden Zustand dass beständig gegen dreyssig 30)Instrumente in Arbeit sind. Der meiste Absatz schränkt sich jetzt nur noch auf das benachbarte Holland und Westphalen ein, wo der Erfinder auf einer kleinen Reise selbst dieses Instrument orführte .." Befeuchtet wurde im Gegensatz zum Clavicylinder dabei nichts. "- Und ohne Gebrauch des Wassers hervorgebracht; der innere ..Mechanismus, hat wol die meiste Aehnlichkeit mit dem, des Chladnischen Klavieylinders, ist aber weniger zusammengesetzt und weit vollkommener ausgeführt."Allgemeine musikalische Zeitung, Band 8, Page 526, 527
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The tuning or retuning to up to a quarter note could be adjusted by screws for each note individually. Readjusting did not have to take place at all if one was happy with the tuning reverence note. The metal structures kept better to the pitch than wooden parts. Dietz also invented the ''chalybssonnans''. This used friction on glass or metal rods by rubbing the rods along their length. The sound was much like the one produced by the glass harmonicas.

References

{{Crystallophones Friction vessels Keyboard instruments Articles containing video clips