Many substances repel faeries, as I have often described; amongst these are sprigs of rowan tree, items associated with the Christian faith, iron objects and, perhaps most understandably, stale urine. The urine (maistir) would be off-putting to anyone with a sense of smell; an aversion to crosses, blessings and pages from scripture make sense if we accept that the faeries not only stand outside the church but (in the view of people from the Middle Ages) were actively associated with the angels who were ejected from heaven along with Lucifer.
Two substances that have regularly been deployed as defences against the Good Folk are similar to each other and might, initially, seem rather puzzling. These are the earth taken from graveyards and from mole hills. Scattered about, they form an invisible but impassable barrier against our Good Neighbours. The earth operates in two ways: it can stop the faeries getting in and, just as effectively, it can stop faery beings escaping. There are several recorded stories from the Scottish Highlands in which captured mermaids or faery cattle (crodh sith) are contained by humans using earth. The cattle are valuable for their rich milk; a mermaid is a novelty and might perhaps become a bride. However, whilst these measures will work for a while, sooner or later (of course) someone forgets to renew the barrier- which generally has to be done everyday- and the captives escape.
The use of churchyard earth is rather easy to explain, I think. It is taken from consecrated ground and, as such, shares its magical power with any other Christian-related item. Any objects formed into a cross (metal scissors, for instance, for double protection) and any items linked to the faith will work, even if there appears to be some sacrilege involved in their use- hence, pages ripped from the Bible or prayer book and carried in the pocket will protect an individual, even though we might assume that the damage to the holy book was, at the least, inadvisable or disrespectful. We might instinctively feel a comparable reluctance to take soil from the location where relatives or fellow villagers are interred, but once again this does not seem to impair the magic inherent in the substance. Then again, perhaps it is that very quality of those ancestors- dead and buried underground- that makes their last resting place so potent. If the dead are related somehow to the faeries, strewing the soil in which they sleep might be deploying like against like.
Why earth from moles hills though? The reason is that moles turn out to have a special place in British folklore. They were once felt to be a cure for scrofula, the ‘King’s Evil,’ and, as such, equivalent to a touch from the hand of the monarch himself. Holding a mole in your hand until it died would imbue you with healing powers (akin to what may be received from faeries). The powdered skin and flesh of a mole would cure the ague (malaria). It was more than just a burrowing mammal therefore.
More significantly for our purposes, moles are obviously subterranean creatures, living in the darkness and seldom seen. As a result- and just like the faeries- they have been linked to ancient burial chambers and cairns. The reverend John Atkinson, in his account of Forty Years in a Moorland Parish in North Yorkshire, records a conversation with a faery in which the supernatural told a man that he and his kind lived underground for “t’moudiwarps dis, an’ wheea not fairies?” (the moles do, so why not the faeries?) It appears that their common habitation below ground created an association between moles and faes and somehow led to traces of one being effective against its ‘neighbour.’
Part of the status of moles may also derive from wider folklore attitudes to small animals. British folklore never seems to have viewed these creatures as just wild mammals. For example, hedgehogs were thought in England to suck milk from cows udders in the fields. They were also believed to act as witches’ familiars and to be able to run as fast as hares. In turn, hares themselves were viewed as unlucky, because they were either witches’ familiars or because they were actually the shapeshifted witches, out and about in disguise and up to no good. Sometimes, too, ghosts or other spirits might take hare form (and see my Beyond Faery for more details of faery hares and other such animals).
To conclude, the British countryside was full of magical beings and plants, whose powers and interactions were far greater and more complex than we appreciate today. Whether we class it as ‘sympathetic’ magic or we see it as a reflection of their shared realm, the earth through the moles passed, being the same realm as that dwelt in by the faeries, could exercise a strong, but poorly understood, control over them.