Violet, say our scientists, is on the extreme edge of visibility! Could it somehow mark a passage between ours and the invisible world?
— Vera Van Slyke, “The Minister’s Unveiling”
The very first story in Help for the Haunted introduces the idea that violet light marks passageways between the spirit and physical realms — but the light can only be perceived by spirits. By the third story, Van Slyke and Lida discover a means to tug that light into the visible spectrum of the living. It becomes the duo’s chief means of confirming supernatural activity.
I became curious about the science behind this phenomenon and did a bit of research. In 1800, William Herschel established that infrared light exists just beyond human eyesight. Inspired by this finding, the following year, Johann Ritter discovered ultraviolet light wavered invisibly on the other end of the color spectrum. He knew that silver chloride turns black at different rates when placed in different colored light: red had little effect, but blue worked much better. So Ritter went further — beyond the violet end. The silver chloride blackened surprisingly quickly. There was something there!
Closer to Van Slyke’s own time — 1895, to be exact — Wilhelm Conrad Röntgen toyed with invisibility in a very new way. He found that rays exist that penetrate physical things with varying effectiveness, depending on the thickness of the thing. And the results can be photographed.
Take, for instance, someone’s hand. Place it over a sheet of photo-sensitive paper. Expose it to what Röntgen started calling “X-rays.” Develop that photo, and you’ll see the bones beneath the flesh. That is exactly what the scientist did with his wife’s hand, and as a result, doctors had a means to precisely locate health threats, be they bullets or bone fractures.
The eerie photographs created via X-rays became a sensation. Spiritualists and others interested in ghosts pounced, thrilled by the idea that — if skeletons could be photographed — why not ghosts? Indeed, dozens if not hundreds of photos already had been offered as proof that the human spirit survives death, and X-rays only seemed to substantiate our ability to photograph the unseen. As early as January of 1897, an article about spirit photography quotes one writer equating X-rays with the Odic force, which had proposed forty years earlier by Baron von Reichenbach to explain everything from crystals to ghost sightings.* Afterward, in his 1911 book titled Photographing the Invisible: Practical Studies in Spirit Photography, Spirit Portraiture, and Other Rare but Allied Phenomenon, James Coates uses X-rays to defend his faith in spirit photography: “To say the invisible cannot be photographed . . . would be to confess ignorance of facts which are commonplace — as, for instance, to mention the application of X-ray photography to the exploration of muscles, of fractures of bone, and the internal organs.” I have a strong inkling that several more analogies between X-rays and ghostly phenomenon were made in the wake of Röntgen’s discovery.
In contrast, Vera Van Slyke was convinced that photos of ghosts were inevitably fake. (She says as much in “Houdini Slept Here,” one of the Help for the Haunted tales.) However, she clearly understood the relationship between the physical spectrum of visibility, its edges and what exists beyond those edges, and even making the invisible visible. Vera managed to shift the ultraviolet (or “ethereal-violet”?) into the violet range — by using sound of all things. But that’s a topic for a future post.
You can read more about Vera’s use of this technique in either Help for the Haunted, which features thirteen of her ghostly investigations, or Guilt Is a Ghost, which chronicles a single, complex supernatural mystery.
*In his Researches on Magnetism, Electricity, Heat, Light, Crystallization, and Chemical Attraction, in Their Relations to the Vital Force, Reichenbach declares that, now that he has identified Odic force, a myriad of “ghost stories will now receive a natural explanation, and will thus cease to be marvellous.” (He later notes that “spectral or luminous appearances, seen over graves, . . . are of purely chemical and physical nature, but can only be seen by the eyes of the highly sensitive.”)