An instrument said to have been constructed under spirit guidance by the Dutch physicists Dr. J. L. W. P. Matla and Dr. G. J. Zaalberg Van Zelst of The Hague to obtain direct communication with the spirit world without using a medium. The device consisted of a cylinder into which the spirit influence was supposed to enter, a table isolated by a sheet of glass and charged with an electric current, a pair of scales, and a writing apparatus arranged on the Morse system. Enclosed in a room, the action of the instrument was observed through a small glass window. Long communications were allegedly spelled out by spiritual intelligences using a lettered dial at the top of the machine.
The result of these investigations was detailed by the inventors in their work Het Geheim van den Dood (5 vols., ca. 1911). A one-volume version was issued in French under the title La Solution du Mystère de la Mort (1930). A report of the Dutch Physical Society objected that no sufficient allowance was made for possible earth tremors and other normal causes. Nevertheless, such objections do not give satisfactory explanation for the curious communications received from the deceased father of Zaalberg Van Zelst.
For a discussion of the work and apparatus of Matla and Van Zelst, see Hereward Carrington, Laboratory Investigations into Psychic Phenomena (1939).
(See also Ashkir-Jobson Trianion ; Communigraph ; Reflectograph )