Its very inaccessibility beneath the City Chambers and its haunted reputation add up to the fine recipe for the historical mythology that the citizens of Edinburgh, however cynical or non-mystical, appear born to relish. When it comes to Auld Reekie, her ghosts and her legends, the locals are all too ready to suspend disbelief - accept the illogical, and keep the witches' cauldron boiling for their own as well as tourists' amusement, thus turning inventive local hocum into innocent pleasure that every body can enjoy.
Mary King's reputation is the inevitable result of a few hundred years of myth and legend coupled with the efforts of some historians who carry on regardless of masses of readily available facts to perpetuate some finely honed folk versions of the Close's history.
Versions which they would not have got away with thirty years ago, or not at least without certain contradiction by any number of local, if ancient, worthies whose memories of the public passage through the Close until 1896 would have ruled out further flights of fancy - and their memories of the people who lived and worked there. Not that the ghostly legend is a recent development - after dark was very much the time for daring High Street bairns in Victorian times to hazard the trip from City Chambers to Cockburn Street by running the gauntlet of Bluidy Mary's restless spirits.
Oh the legend is lively enough and long may it last, but the real story of the Close is a remarkably resilient one - and in many ways a tribute of the people of Old Town Edinburgh. Like other and bigger lumps of Scottish History, Mary King's Close became a propaganda vehicle for a certain 17th century religious nutcase - who, with a scientific education and a professorship at Glasgow University should have known better.
Unlike however, the legitimate benders of historic fact - storysmiths like Scott and Stevenson who could apply their splendid literary imaginations to history, and produce acceptably better versions than any of the boring old dates and places stuff - this character chose the path of many religious and political zealots and Scotland has never been short of either to bend historic fact to his own end. Thus, giving credance to the legend of Mary King's Close.
Professor George Sinclair was his name and he has even been cited as an eminently qualified and reliable source to offer the truth about ghosts in the Close. In fact, and flying in the face of his otherwise scientific background, George was a seventeenth tub/thumper who believed implicitly in the efficacy and evil of Witchcraft, the reality of Spirits and Apparitions and published in 1685 his book "Satan's Invisible World Discovered" to prove his point. This was at a period of public frenzy over witchcraft and demonology and the Professor knew how to pander contemporary taste for prophet as well preaching his own form of Fire and Brimstone.
Dolls left by visitors claiming having felt a presence
The story of Mary King's Close, her wraithes and spirits, is only one small section of this highly imaginative catalog of Satanic catastrophy that must have hit an eloquent note at the time. And a lasting one at that, since it has lasted a full two hundred years without the benefit of TV serialisation.
It is however, doubly ironic that the nature and manifestation of Mary King's spirit, supposedly 1645 plague victims, could have some basis in fact, and that that fact should be directly related to one of George Sinclair's areas of scientific studies. One is driven to suppose one thing lead to the other, and that George, far from being taken in himself, was using his scientific knowledge to put a nefarious fear of death into his superstitious readers.
Sketch of Nor'Loch
Of all the city's closes, Mary King's ran closest to the Nor' Loch and the Nor' Loch did not run anywhere. In fact, it sat there and stagnated, fed not only by the city's sewage and seepage from the so-called "irrigated gardens" that lay between the last of the houses and the Nor' Loch, but with all of the animal and vegetable waste discarded from the market on its Eastern edge. It was not a loch at all, it was a stinking miasmic kloake, and as such an ideal generator of marsh gas, natural gas or methane. Marsh gas displays all the classic symptoms of ghostly visitation and every low-lying area in the world has mythologies of hauntings by grey ladies, bearded old men and other wraithe-like spirits. Marsh gas is lighter than air and hovers, with a slight luminous glow until dispersed or dissolved in the air, and given the right mixture will burn with a blue flame. Take off Edinburgh's few wind-free days; and it is not difficult to picture the effects of wispy gas pockets collecting in the houses of the Close's nether regions - trapped and unable to escape upwards, and with insufficient air, unable to dissolve quickly.
Princes Street Gardens nowadays
One of George Sinclair's professorial specialities was the effect of "Damps and Wildfire" in Coal-mines, and although the subject was by no means fully understood in 1685, he must have had acknowledge of methane gas that could have been used for reassurance and not for raising Cain. Such are the whims of odd-ball extremism.
This gas theory may not hold water with devoted ghost followers but it is relevant to note that sightings of the spirits ceased with the draining of the Nor' Loch around 1760 - coincidentally simultaneous with the building of the first stage of the present City Chambers.
The stories of Mary King's Close's disappearance from public view and public residential favour are based on two events:
Its haunting after the plague of 1645 and a consequent reputation for pestilence (also no doubt due to its close proximity to the Nor' Loch sewage system) together with the building of the City Chambers (or Royal Exchange) under which it was reputedly "swallowed up".