"But as the history of invisibility shows, myth is no blueprint for the engineer. It is more important than that." Philip Ball concludes his journey from witchcraft to warcraft with this portentous final sentence which aims to link ancient cultural anxieties about invisibility to modern attempts to use metamaterials and a "negative refractive index" (the way that science is learning to master invisibility, through optical manipulation).
He's written a guide that takes us from Lydian shepherds via Robert Hooke to BAE Systems. Invisibility: what used to be the ultimate magic spell has devolved into whisking hard power into thin air, and what used to be a notion replete with sexual, voyeuristic and moral perils is now simply the warehousing of death.
For Plato, invisibility was not only a wondrous power but a moral challenge, and he is one of several ancient sources for the story of Gyges. Gyges was a shepherd who chanced upon a magic ring; once liberated, the ring is revealed as having the power of invisibility. Soon this bucolic swain has killed the king and ravished the queen, all done with the aid of invisibility.
J R R Tolkien's Lord of the Rings deploys this story for Gollum where it slips its user deathwards like a kind of moral radiation. In other versions of the invisibility myth, it's a helmet that infers invisibility – Athena gave Perseus a helmet that masked him from view, and Homer refers to a "Helmet of Hades". The invisible is the realm of the ghostly. The cloak of invisibility – familiar in Harry Potter books – starts life in a Grimm's fairytale where an old soldier uses it to spy on dancing girls. Did Harry really never use it to visit the girls' showers?
Until relatively recently the idea of becoming invisible has always been cast as a moral test. H G Wells, who wrote The Invisible Man in 1897, rejected film script after script when Hollywood failed to grasp his key central point – that it is the invisibility itself that drives the protagonist insane, not the potion he took to make himself invisible.
Invisibility is a constant social preoccupation. A quick, unscientific survey of recent news items reveal features on the "invisibility" of cyclists and the "invisibility" of women on BBC TV comedy shows. Here, solving invisibility is presented as a good thing. Being invisible these days is still seen as a moral danger.
Apart from the ghostly, I count in this book three categories of the non-paranormal invisible. "Glamour" where invisibility is thrown over something like a cloak, "dazzle" where artifice produces a misdirection effect, and finally something unnoticed that is simply incredibly small and unobserved (bacteria, viruses) until the requisite technology comes along. Is it better to cover or uncover? As a species we're hardwired to fret about invisible forces, and the idea of being deceived haunts and appals us. We're obsessed with identifying deception as an ancient survival skill.
This is an enjoyable, well-written book, but I'm not sure the two distinct halves fit together. The first is full of spells, arcana, myth and apparitions, with material that will be familiar to anyone who reads on the subject – some of which, I daresay, is also present in my book which touches on the subject, A Natural History of Ghosts. That said, there were details here that I really didn't know. Magic?
Witchy spells recounted here in their entirety are riveting in their mountebank oddness. They are elaborate, unwholesome and bizarre; supercharge a garden bean with supernatural power and pop it in your mouth and you will be granted invisibility (Pythagoras always associated beans with ghosts). There are familiar accounts concerning the origins of the Society for Psychical research (described as 'an odd beast' by the author) and the scientists around it, and of fabricated theatre phantoms including Pepper's Ghost.
In the end I'm not sure whether we quite grasp "the dangerous allure of the unseen" as proposed in the title of this book, and I get the distinct feeling that this book would have been better had the author sat with it and let it settle a few more years.
Ball makes a good case for our weird and usually irrational fascination with invisibility, though the possible moral downside, so very clear in myth, is nowhere near so cut-and-dried in the practical problem-solving realms of advanced science.