The device that Simeon de Florence builds (and which Albert operates) in The Bridge of Dead Things is a form of Pepper’s Ghost, an elaborate stage illusion that became popular in the 1860’s. Stage magic is often referred to as being “all smoke and mirrors”, which is apt since Pepper’s Ghost relies heavily on mirroring. It uses the reflective properties of a sheet of glass—set at a 45-degree angle to the audience—to reflect a hidden space where the so-called “ghost” resides, but only when it is illuminated by some carefully-managed lighting. Visit Wikipedia to see some excellent diagrams which demonstrate exactly how Pepper’s Ghost works.
It is called Pepper’s Ghost after the London Polytechnic’s science lecturer and director, John Henry Pepper. Pepper was the first man to build a full-sized version of the illusion based on plans by an engineer named Henry Dircks. Its debut was marked by a Christmas Eve production of the Charles Dickens play The Haunted Man in 1862. The public was amazed by what it saw, as were the many eminent scientists who would come back to the theatre time and again to try to figure out how the effect was achieved. Pepper was quite the showman, so it’s natural that his name became associated with the illusion. But Henry Dircks, Pepper’s partner on whose work it was based, felt cheated out of his proper recognition; he became increasingly convinced of a conspiracy directed against him by Pepper, the Polytechnic, and the newspapers of the day. It’s for this reason that I decided to use his name in the novel—though ironically, once again, he is not associated with Pepper’s Ghost; instead he’s cast as the engineer who builds the lightning machine.
If Pepper’s Ghost provides the mirror part of “all smoke and mirrors”, the lightning machine most definitely provides the smoke. It is in fact a Tesla coil, a kind of transformer that produces extremely high voltages, first conceived of and patented by Nikola Tesla in 1891, but only developed as a full-scale lightning machine when Tesla moved to Colorado Springs in 1899 (because the town promised him free electricity!). Since The Bridge of Dead Things is set in 1885, the machine that Mr Dircks builds is something of an anachronism, coming as it does six years before its time. But the fact that Sir William Crookes, whose relationship with Florence Cook inspired the novel, also experimented with extremely high voltages made it too tempting to resist.
The Pepper’s Ghost effect made its way into the 20th Century when it was adopted by Walt Disney to provide the special effects for their Haunted House ride at Disneyland. It was the tail end of the 1960s and, thanks to science, holograms and holographic images were becoming a reality. Disney steadfastly refused to say how their effects were achieved, encouraging people to believe they were seeing some kind of hologram, though in fact it was simply the reincarnation of Pepper’s Ghost at work.
More recently still it was used again, this time employing footage of the rapper Tupac Shakur, killed in 1996, to make it look as if he’d been reunited on stage with fellow rappers Dr Dre, Snoop Dogg and Enimen at the Coachella festival in California in 2012. The singer Pixie Lott also used the same technology to appear live in concert as a “hologram”. As long as people have distinctly short memories, everything under the sun can be made to seem like something new.