The "Ondes Marthenot" is an electronic musical instrument, based on
a high-frequency generator.  It was invented by the French engineer
Maurice Marthenot in 1928, four years after the introduction of
Theremin's "Aeoliphone".

While Theremin (a man of Russian origin, who went back to Stalin's
Soviet Union somewhere in the thirties!) made an instrument with two
antennas (one for regulating the pitch and one for the volume), the
Marthenot instrument had a keyboard for playing and a kind of antenna
upon it for modulating the sound.  The Ondes Marthenot has been used
by some modern classical composers like Karlheinz Stockhausen.

The word "Bioscoop" is still in use in the Netherlands for a movie
theatre, whether in a tent or building.  Mr. Welte had nothing to do
with the Freiburg company.  The Welte traveling "bioscoop" has been
acquired by the Netherlands Openluchtmuseum in Arnhem (where the annual
KDV festival is being held).  The 89-key Gavioli organ that went with
the show is now somewhere in the US, after recent restoring by Johnny
Verbeeck in Belgium.

Best regards from the Netherlands,

Hans van Oost