Spiritualist medium used toxic chemical

In the 19th century, spiritualist mediums used white phosphorus, a toxic industrial chemical, to simulate the appearance of spirits during séances, according to a historian from Queen's University.

Historian's analysis published online

Aditi Sen, a historian at Queen's University in Canada, published an analysis on October 26, 2026, in The Conversation detailing how white phosphorus was used in these practices. The findings are based on historical archives and accounts from the time, rather than laboratory experiments.

First recorded use in 1857

The use of white phosphorus in spiritualist practices dates back to November 1857 in Jersey City, United States, during a séance led by the medium Leah Brown. According to her memoirs, Brown claimed that her body emitted luminous particles during the séance, which nearly burned her hands.

Phosphorus found in soil

She rinsed them under a tap and then buried them in damp soil outside. The next evening, luminous particles appeared at that location, later identified as phosphorus. Brown acknowledged the presence of phosphorus but claimed it was produced by her body as part of the manifestation of spirits.

Link to ectoplasm and chemiluminescence

She linked the phosphorescent lights to ectoplasm, a substance mediums claimed to secrete during trances. However, according to Sen, Brown likely brought the phosphorus secretly. When white phosphorus comes into contact with oxygen, it undergoes a slow chemical reaction, emitting a faint light known as chemiluminescence.

Toxic effects of white phosphorus

White phosphorus, however, is highly toxic if ingested and its vapors are harmful. It was commonly used in the production of "friction matches" during the 19th century. Many female workers in these factories suffered from its effects.