Experiments in psychical science : levitation, contact, and the direct voice
A 1919 parapsychology book by W. J. Crawford, published in New York by E.P. Dutton & Co., describing experiments in levitation, contact, and the direct voice, likely for researchers and readers of spiritualist claims. The pictures are plain line diagrams with lettered parts, labelled levers, pivots, and a table, with arrows marking forces and motion, which a designer might borrow for clean schematic or technical-drawing styling.
