For John Henry Pepper, the Christmas Eve of 1862 promised to be one that Londoners would not soon forget. If all went well, he would be the man responsible for making a skeleton come to life on stage.

A lecturer and analytical chemist for the Royal Polytechnic Institution, Pepper was man of science with a reputation for showmanship. He attracted throngs of people to the institution with elaborate demonstrations that were part scientific principle and part stage show.

Sometimes, there would be more spectacle than science. For the holidays, the Polytechnic was mounting a production of A Haunted Man by Charles Dickens. In it, Pepper was about to utilize an optical effect that’s still in use today.

During a private performance earlier that day for select guests, Pepper watched as the skeleton appeared on stage in ethereal form, seemingly present but with the hazy definition of a ghost. Pepper had planned to disclose the secret of the trick, but the audience’s reaction—they were stunned—gave him pause.

For a time, the trick was the talk of Victorian London, with people regularly flocking to performances that featured it. And while it was dubbed "Pepper’s Ghost" after the man who popularized it, it was not entirely his. The concept had originated with a man named Henry Dircks, who would watch with no small amount of frustration as his concept made Pepper one of the first “celebrity” scientists in history.


John Henry Pepper was born in London on June 17, 1821. Educated at King’s College School and the Russell Institution and later employed as an assistant lecturer in chemistry at the Granger School of Medicine, Pepper was uniquely suited for the brewing scientific curiosities of Victorians.

At the time, it was not unusual to see scientists provide demonstrations of experiments involving light, energy, and the human body. Pepper was a born showman, having taken an interest in theater and realizing that scientific concepts could be more easily understood when they were wrapped in the guise of a show.

Cyclopaedic Science Simplified (1873) by John Henry Pepper illustrated some of his science demonstrations conducted at the Royal Polytechnic Institution in London, like this one involving spectrum analysis.Oxford Science Archive/Print Collector/Getty Images

When he arrived at the Royal Polytechnic Institution in 1848, Pepper was all too willing to cater to the Polytechnic’s desire to draw crowds and make science a form of spectator entertainment. Founded in 1838, the institution was intended to celebrate invention and ingenuity. There, Pepper beckoned audiences with promises of displaying the world’s largest and smallest photographs—one a life-sized portrait, another a tiny reproduction of a newspaper’s front page. (Pepper used The Times for the exhibition, pretty much guaranteeing a good notice in the paper.) He demonstrated harps that could play music without being strummed by hands, instead delivering acoustics from the conducted sound of musicians playing instruments several floors below. During a lecture on the art of balancing, he had a trapeze artist navigate a tightrope. Such stunts attracted everyone from the curious to Queen Victoria and Prince Albert, who attended a performance in 1855.

Though there was no academic justification for the title, the Polytechnic’s owners began referring to him as “Professor” Pepper, the man who could command a stage while illuminating science. By 1854, he was in charge of the Polytechnic’s operations and remained a fixture until 1858, when he left over a financial dispute.

In 1861, Pepper settled his differences with Polytechnic and returned as managing director. He was eager to increase the the Institute's profile even more, and he believed the solution resided in the work of Henry Dircks. An engineer, Dircks had made a presentation during a British Association for the Advancement of Science meeting in Leeds in 1858 in which he described a “model of phantasmagoria” for theatrical purposes.

The trick was not actually new. A version of it had been described by Giambattista della Porta in his 16th century book, Magia Naturalis (Natural Magic), and it was remarkable in its simplicity. The goal was to make an object behind a person appear as though it were in front of them.

The easiest way to imagine that is to think of looking out a window at night and seeing something behind you—like a lamp—reflected in the glass. It’s not technically an illusion, as the object is being reflected with accuracy, but it does function as an optical trick for the observer.

Dircks described a set-up in which a compartment would be located under the seating area in a theater. Inside, an actor would be illuminated by oxyhydrogen-driven light. That light would be reflected off a large pane of glass on stage. While the glass would be invisible to the audience, the reflection would not be, and the actor in the compartment would appear as though he were on stage. The light would make it seem as though a ghost-like apparition was present. If the actor was wearing a black coat and manipulating a skeleton, then the skeleton would appear to be moving.

The idea was intriguing, but Dircks had not uncovered a way to mount such a production in existing theaters and no theater managers seemed to want to work with Dircks to pursue it. But when Pepper discovered the idea, he partnered with Dircks on the premise that Pepper could make the trick work with only minor adjustments to the stage area.

Pepper situated the actor in the orchestra pit, then tilted the pane of glass 45 degrees toward the audience while simultaneously matching the actor’s angle on a board so he could be more easily obscured. It seemed to work, and Pepper knew it would astound spectators at the Polytechnic.

Dircks and Pepper entered into a business arrangement in which they filed for a joint patent, with Dircks inexplicably agreeing to sign over all financial rights to Pepper. Originally marketed as the “Dircksian phantasmagoria,” it quickly became synonymous with Pepper. Then and now, the illusion—a joint effort between the two men—was referred to as "Pepper’s Ghost."

Following its successful debut in 1862, Pepper’s Ghost became a regular part of the program at the Polytechnic, and Londoners circulated word of the incredible effect. Any actor could be made to seem weightless and somewhat transparent. In ads, the institution made note that it would be possible for people to see a “living being” seemingly “walk through” another person, a feat achieved when an actor strolled behind the glass.

A common reaction was recorded in the July 17, 1863 edition of The Nottinghamshire Guardian, in which a spectator wrote:

“The appearance of the Ghost, as an optical illusion, is one of the most remarkable discoveries of modern science. The apparent reality of the spectre puts into dim shade the living individual, who performs his part in the haunted chamber, rendering him more like the dark shadowy representative of a ghost, than the ghost itself ... [Pepper’s] observations on the laws of light were also very interesting, and his experiments in illustration of some of those laws, were highly instructive and amusing.”

The Prince of Wales and his wife came to see it for themselves in 1863 and were so impressed that the prince became a patron, restoring the “Royal” designation the Polytechnic had once lost. In a short time, Pepper earned around £12,000, or about $1.5 million in today’s dollars, from people eager to see what everyone was talking about.


While Pepper’s Ghost helped make the Polytechnic a popular attraction in the 1860s, the novelty eventually wore off. Other theaters tried a similar trick with only mixed results. The lighting, glass, and even proper rehearsal—because actors couldn’t see the reflection on stage and would have to move carefully—all had an effect on its success.

The 'Pepper's Ghost' effect used a large pane of glass to project an image of an actor hidden below the audience's line of sight.Wikimedia Commons // Public Domain

Even when done properly, audiences wanted some variation. Pepper was able to use the trick to debunk spiritualism, then a popular topic, and even demonstrated levitating tables to crowds to illustrate how easily they could be fooled by people claiming to be able to communicate with paranormal entities.

Ultimately, what Pepper discovered was that people were interested in the spectacle. He was a kind of magician, and in their eyes, needed to produce increasingly elaborate effects to hold their attention. With assistant Thomas Tobin, he developed a magician’s cabinet in 1865 that used mirrors to obscure objects inside a box, making it appear empty. In 1866, he again held a lecture on balancing at the Great Hall, this time using an automaton on a trapeze that delighted spectators.

The Polytechnic had its last Christmas show in 1871. Pepper left the institution in 1872 to go perform at the Egyptian Hall, a popular theater for magicians, but turnout was poor. He then left the country to deliver lectures internationally. When he briefly returned to the Polytechnic in 1878, he had a new illusion, one in which he turned oranges into pots of marmalade and handed them out to audience members.

Pamphlets and books based on his lectures grew popular, and in 1890, he published a book on Pepper’s Ghost, The True History of the Ghost, which had clearly become his lasting legacy. He died in 1900.

Dircks had also published an account of the trick and its evolution back in 1863. (He passed away in 1873.) He was said to be irritated over how closely it came to be identified with Pepper, who had improved on it but was not its sole innovator. It soon became something of a parlor trick, with carnivals using it for a popular “girl to gorilla” illusion in which a woman seemingly appears to turn into an ape with some careful manipulation of lighting.

Today, the “trick” of Pepper’s Ghost lives on, both in amusement park attractions like The Haunted Mansion, where ghostly figures appear, and in “holograms” like the one that seemingly made the late rapper Tupac Shakur resume performing at the Coachella Valley Music and Arts Festival in 2012.

It’s also used heavily in television production, where teleprompters allow broadcasters to read scripts while looking directly into the camera lens. Perhaps it's fitting: John Henry Pepper spent much of his life trying to deliver information with a simple trick of the light.