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How a scientific illusion became a fierce gorilla
JOE SCHWARCZ
Freelance
Sunday, April 04, 2004
I think it must have been around 1960 when I was attacked by a gorilla. It happened at Belmont Park, a classic old-time amusement park in Montreal where side shows were a hot attraction. Large canvases with peeling paint advertised fat ladies, sword swallowers, living skeletons and a "gorgeous woman who would magically transform into a ferocious gorilla in front of the spectator's eyes." This I had to see!
After paying a quarter, I was ushered to a corner of a large tent where a cabinet, somewhat larger than a phone booth, had been set up. Judging by the gaudy picture of a half woman-half ape that adorned the side of the contraption, it was clear that this was where the miraculous transformation would take place. Indeed, as the lights came on, we saw a lady shackled to two posts inside the cabinet. She seemed pretty harmless to me, so why she had to be shackled wasn't clear. I thought the whole thing would probably turn out to be some sort of scam, like the "living skeleton" who was actually just a very thin man. But no! Truly as if by magic, the lady slowly morphed into a gorilla, growled fiercely and began to vigorously rattle its chains. Then, as the noise got louder, and the gorilla's struggle intensified, the shackles suddenly gave way and the beast bolted from the cabinet, scaring the daylights out of me and the rest of the gathering. We scampered towards the exit. When I looked back, the man in the monkey suit was gone, and the next group was already being assembled in front of the cabinet.
I didn't realize it at the time, but I had just witnessed one of the greatest scientific illusions ever devised. I had just seen Pepper's Ghost. Actually, if you really want to get technical, it was really Dirck's Ghost, as modified by Pepper. To understand what all of this means, come back with me for a moment to Victorian London. The date is Dec. 24, 1862, and you're sitting in the audience at the Royal Polytechnic Institute in Regent Street. You have heard of the wonderful lectures put on by "Professor" John Henry Pepper and have come to be entertained by his scientific experiments. The Polytechic, founded in 1838, was sort of a permanent science fair to which the public flocked to view the latest technological marvels and listen to fascinating lectures. The most entertaining presentations were by John Pepper, who had been captivated by chemistry since childhood and now revelled in bringing science to the public in a theatrical fashion. He explained the workings of steam engines, diving bells and poisons. Then, using a projection microscope and a giant screen, he terrified the audience by showing microbes cavorting in a drop of London drinking water.
On this December day, though, the professor had something special for his audience. The curtain went up to reveal a scene from Charles Dickens' The Haunted Man. A student was seen hunched over a desk, when suddenly a ghostly skeleton appeared and seemed to float right through him. The audience burst into spontaneous applause at the appearance of Pepper's Ghost.
Pepper, as manager of the Polytechnic, had always been on the lookout for novel acts and demonstrations. So when a Liverpool civil engineer named Henry Dircks approached him with an invention he claimed would astound audiences, Pepper was ready to listen. Dircks asked Pepper to look down into a box he was holding. As Dircks manipulated a flap on the side of the box, Pepper was absolutely flabbergasted to see the appearance of little ghostly characters. The "ghosts," Dircks explained, were reflections of figures hidden in the box in front of a glass plate. Unless they were lit, all that was visible was the back of the box through the glass plate. But when a flap was opened to let in some light, the figures were reflected in the glass, with their image appearing to be as far behind the glass as the figures were in front of it.
Actually, we have all witnessed this phenomenon. Just think about what you see when you look out through a window from a lit room into the dark night. Reflections of objects in the room appear to be floating outside. To his credit, Pepper recognized the potential of Dircks' discovery for producing theatrical effects. He designed a large glass plate for the stage, tilted towards the audience at a 45 degree angle. A second, essentially identical stage, was built where normally the orchestra pit might be. This is where the "ghosts" cavorted in front of black drapes. When this stage was dark, the audience just saw the scene behind the glass plate. But as the limelight slowly came on, and the illumination on the real stage dimmed, the reflections of the characters appeared as if they were transparent ghosts. With proper synchronization, they could even interact with the actors on stage.
Some in the audience believed they had seen a real paranormal event, but Pepper was quick to explain that it was all a trick of science. He then went on to castigate the spiritualist mediums, who were very popular at the time, suggesting that they also used tricks to prey upon the gullible. Today, if you want to experience the most spectacular display of Pepper's Ghost ever created, just visit the Haunted House at a Disney theme park. Or, if you're lucky, you can still find a carnival where a woman turns into a gorilla.
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Joe Schwarcz is director of McGill University's Office for Science and Society (http://www.OSS.McGill.ca). He can be heard every Sunday from 3-4 p.m. on CJAD. [email protected]
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