Roots: Arthur C Clarke's oft-quoted 'Third Law' about science and magic. 'Odic force', a theory of vitalism, was a nineteenth century belief devised by Baron Carl von Reichenbach "An eye for an eye and we all go blind" paraphrases a quotation attributed to Mahatma Gandhi. Mary refers to Milton, Rubens, Claude, Senor Galvani (see; Links) and Purcell and likens the stricken traders as "marooned like Selkirk was" [referencing Alexander Selkirk, the inspiration for Daniel Defoe's Robinson Crusoe]. She also refers to the legend of Prometheus. Norse mythology (Lokic and Odic energy from Loki and Odin, a 'vaettr' is a barrow-haunting creature, an inspiration for Tolkein's barrow-wights); the Hecatryx dimension likely takes its name from the Greek goddess Hekate, reputed to be the mother of all witches. The Doctor implies Twitter "I doubt these two have any more than 140 characters" and mentions Debrett's Peerage. He quotes Mary's future writing from Frankenstein, Chapter Eight: "All judges had rather that ten innocent should suffer than that one guilty should escape." His reference to "The right chords, just not necessarily in the right order" is a nod to the 1971 Morecambe and Wise sketch with Andre Previn. Witchfinder General.
Intertextuality: The Doctor's line "Genuine evil is rarer than Chelonian teeth" references the Chelonians, a militaristic race of alien tortoises created by Garth Roberts in his New Adventure The Highest Science. The Chelonians reappeared in two further Virgin novels by Roberts (Zamper, The Well-Mannered War) as well as a DWM Yearbook story (The Hungry Bomb) before being mentioned by name in The Pandorica Opens.
Technobabble: The TARDIS' sequential regression takes the Ship to the edge of the Vortex
Dialogue Triumphs: "Two more victims in a holocaust of victims - ages long and a universe wide"
"Less verbosity, Doctor, more alacrity"
Alistair on the biography of Mary: "I feel pretty sure the Doctor has the first edition - the original, as it were..."
"Prometheus Unfettered? You might wanna work on that!"
Double Entendres: "You'd be surprised by the number of times Lord Byron spent hiding behind women's skirts"
"Now that is the trouble with you modern girls - no stamina"
Continuity: Lokic and Odic energies are arcane and operate outside normal physical laws; being antithetical energy forces they cancel each other out. Evolution produces rare minds in every race that are able to channel Odic energy; most individuals so-attuned typically become healers, prophets or madmen.
Varaxils are, perhaps, immortal, being able to endure three hundred years or more without ageing. They know of Time Lords and of Gallifrey and keep to themselves. Their technology is based on Lokic energy, harnessing the paranormal so their science is indistinguishable from magic. Many enlightened races denounced the Varax sciences as heresy and persecuted them throughout the galaxy, and in turn, two centuries ago, the Varaxils turned on the Odics among their population and spread their campaign of persecution across the cosmos, swearing to eradicate Odic mutations across all space and time and seeking out other Odics on other worlds to imprison them alive deep below the surface of Varax Beta in tombs of reinforced terilium. The Doctor says there are no witches anymore except 'the witch dimension of Hecatryx.' Artefacts from the Hecatryx Dimension enabled the Viraxi to reverse the effects of their magic. Hecatryx technology is volatile in the presence of Lokic energy, and is unstable in 'ours.' The Witch Star configuration - outwardly a garish pendant, is the pinnacle of Varaxin technology and contains the essences of those it finds, as well as detecting Odic potential in an individual and trapping it through its Odic energy - previous captives include a Felcat Flux Imp (see below) and an Erisi (see: Links). The Doctor rigs the Witch Star's containment field to filter out the Odic energy, entrapping only an 'Odic waveform.' Six months before the witch scare a Varaxil ship was lost crossing the solar system and fell on Vetter's Tor last "spring" The ship's transmutation matrix allows Varaxils to assume other forms. Carvings on the stone-capped well are Vraxilian runes
Felcat Flux Imps originate in the Fairdac Array, 418 light years away; they can channel Odic energy. Geldrium, a metal from Tridentia III glows when you shake it .
The TARDIS database is "greater than Alexandria" - the Fast Return switch is engaged "by accident" and brings the TARDIS to the Folly.
Mary is told by the Doctor that the TARDIS Library has "billions" of books. It contains a volume called The History of the Varaxil Hegemony as well as a biography of Mary Shelley.
The Doctor mentions to Finicia and Lucern that Mary "tends to side with the monsters." He has a dozen or more pieces of geldrium with him either on his person or in the TARDIS.
Location: Tranchard's Folly, 2011, and Vetter's Tor, Tranchard's Fell, 1650. Three hundred and fifty years separate the events, and the Doctor and Mary.
Links: Mary refers to Cybermen in Vienna (The Silver Turk) and Senor Galvani, who was also mentioned in Mary's Story. The Doctor's secateurs are in the TARDIS Library "under 'B' for 'Capability Brown' (The Doomwood Curse) "Please don't disturb the Erisi" refers to Briggs' The Entropy Composition. The Doctor's quip "Next time I'm going to go for a shorter jacket, in a more durable material" could either be a reference to his Dark Eyes wardrobe or, more likely, that worn by his next incarnation (whose jacket is genuinely shorter)
The Bottom Line: "Kids today - no sense of wonder"
Somewhere in this story of doubles (two witch hunts, two witches, two squires, two time periods, one set of twins) there's a pretty interesting parable of the formerly persecuted exacting their suffering on others. The guest performances - particularly Simon Rouse and Andrew Havill are excellent, even if Andrew Havill's voice resembles that of Peter Davison's to the point of distraction. Mary's well used, and the split time zones are handled pretty well - though we'd gladly swap the ropier performances and lines of the twins for more of Agnes. For the Mary trilogy then it's two for two, although this doesn't quite hit the mark of Platt's debut.
SCIENCE AND MAGIC
In Battlefield Arthur C Clark's Third Law applies, albeit with the Doctor's corollary (magic being indistinguishable from science). Indeed, throughout Doctor Who and despite its main character's professed disbelief in the supernatural, science and magic, witchcraft, and the paranormal have sat relatively easily together. Azal's race from The Daemons are themselves extra-terrestrial beings, and while in that story the Doctor trumps Miss Hawthorne's white magic beliefs with a demonstration of Bessie's gravity inertia drive, there are opportunities to reason that although in this example science rules over magic, the two are not necessarily (in a cultural sense at least) mutually exclusive.
The Hekatryx dimension in The Witch From the Well allows for a scenario where what we would call magic has evolved as a matter of fact. In this case 'magic' seems to be the manipulation of matter through psychic will, or what the story describes as 'potential' evident in only certain rare individuals (these individuals are uncommon enough in our universe, but one assumes the elemental nature of the Hekatryx Dimension allows for it to be so much more prevalent.) This brings with it an interesting notion: if the traditional Doctor Who supernatural creature can be described as being someone from another time or place where what we would regard as extraordinary is instead quite ordinary (rather like Superman's powers being remarkable on earth but commonplace on Krypton), what do we make of individuals with such powers who are in theory present everywhere in the universe?
Perhaps Witch from the Well's 'Odic potential' is merely an example of something even more varied and universal, explaining not only the ability for a very small number of individuals from all over the cosmos to display innate natural talents indistinguishable from magic (to which we could also add those with non-species gifted psychic potential, for example), but also an understanding of higher (i.e. arcane) philosophies and sciences - the philosophers, alchemists and astrologers of various worlds. This albeit generous and vague categorisation would at least offer some explanation for those otherwise normal human beings such as Lady Peinforte in Silver Nemesis (able to concoct a time-travelling potion with no explanation) and the alchemist and necromancer Maximillian (The Ghosts of N-Space) to subvert the laws of nature while otherwise existing within them and without obvious alien or extra-dimensional assistance.