Eric Magnesia Campbell Tigerstedt (1887-1925) was a Finnish inventor, commonly called "Edison of Finland".
He improved and devised some important things:
- Sound movie - In 1912, Tigerstedt made first experiments in making optical soundtrack on film, producing a working photomagnetophon.
- Tigersted also improved the design of vacuum tubes, mostly to improve the quality of the aformenetioned sound recording method.
I got information from this web page: http://www.netti.fi/~oh1kw/tiger.html