Leslie Flint was tested by many scientists. Experiments would see him
tied to a chair, gagged and holding a mouthful of coloured water, which
he had to empty into a glass at the end of the test to prove that he was
not a ventriloquist. A Dr Louis Young invented most of these tests and,
along with members of the Society for Psychical Research, carried out
further tests in infra-red light with a microphone attached to Leslie’s
throat. Still the voices were recorded.