This Victorian ghost book exposed spiritualist frauds with cool optical illusions

Spectropia (1864) by J. H. Brown (Public Domain)

In 1864, a peculiar book called "Spectropia" offered Victorian readers a scientific way to summon ghosts. As the Smithsonian reports, author J.H. Brown created this "toy book" to combat what he called "the absurd follies of Spiritualism" during an era when séances and spirit mediums were gaining popularity.