SCOTTISH PHYSICAL medium of Glasgow, a packer in a warehouse,
and a small shopkeeper who accepted no remuneration for his sťances and
used no cabinet. He was controlled by White Feather, an American Indian, a genial personality who prefers to be called Whitey. He
(Whitey) spoke through the medium's (Sloan's) vocal organs and direct through trumpet. To have the medium at the disposal of the British College of Psychic Science,
Hewat McKenzie found employment for Sloan in a London garage and made him accessible to various experimenters. After his return to Glasgow he was experimented with for five years by
J. Arthur Findlay. In 1924 he published a small book on his findings:
An Investigation of Psychic Phenomena with a preface by Sir William
Barrett. This was followed by a larger volume: On the Edge of the
Etheric, in 1931, in which Findlay grades his evidential cases A1 and A2, according to the quality of the evidence. Examining three of the 180 A1 communications he says:
"An eminent mathematician on calculating the chances of correctly guessing all the facts recorded, answers that to have reached such accuracy, represented the equivalent of 1 to 5,000,000,000,000, in other words the odds were 5,000,000,000,000 to 1 against chance being the explanation."
Source (with minor modifications):
An Encyclopaedia of Psychic Science by Nandor Fodor (1934).