An instrument invented by F. R. Melton of Nottingham, England,
consisting of a box inside of which was a rubber bag connected
with a pair of earphones from a radio set. The idea was
that if a medium inflated the bag with his or her breath and
then sealed it, the bag would take the place of the medium and
direct voices would be heard through the earphones in his absence.
The psychical researcher Harry Price subjected the instrument
to a thorough test in the National Laboratory for
Psychical Research, London. It did not work.