Strange incident at Harlech 1694

Strange incident at Harlech 1694

It wasn’t a UFO or a will o’ the wisp – or any other unexplained phenomenon that fits the standard rational explanation. What happened in Harlech in 1694, however, must have been a terrifying display of nature’s powers as it made an unexpected foray upon the people of this part of Merionethshire. It was almost like a volatile gas that killed animals, caught fire in grass, and caused buildings to self-ignite. According to one source, it was caused by a plaque of locusts that had crossed the Atlantic and drowned near the Welsh coast, the numerous rotting carcasses fermenting and emitting this dangerous gas.

Few will know what the word mephitic means – here’s one such definition: ‘a foul-smelling or noxious exhalation from the earth; a stench from any source.’ The word comes from the Latin mephīticus pestilential.

How this incident which revolved around a foul smelling vapour, the mephitic gas as it was known, and came to the world’s attention, can be attributed to a certain Reverend:

‘In the year 1694, the Rev. Mr. Jones, of the parish of Llandanwg, transmitted to the London Philosophical Society an account of a singular phenomenon which had appeared in the neighbourhood, namely, a kind of fiery exhalation, or mephitic vapour, which arose from a sandy marshy tract of land, called Morfa Bychan (the Little Marsh), across the channel, eight miles towards Harlech, and injured much of the country by poisoning the grass in such a manner as to kill the cattle, and to set fire to hay and corn ricks for nearly a mile from the coast. The cause of this singular phenomenon has never been satisfactorily accounted for.’ (Source: Wanderings in North Wales 1853.)

On the basis of the facts being presented by just one person, was this in fact a myth propagated at the time? Or was it a real event? The noted Welshman Edward Llwyd penned a letter on 23rd August 1694 to the same society describing the events that were currently to be experienced in the Harlech area. Edward Llwyd was a dedicated historian and archivist on Wales, so there’s little reason to doubt his words. However the information, as Llwyd so clearly points out, came from a person he deemed to be intelligent and sober, so its rather difficult to argue with that. Here’s an extract from a letter penned by Llwyd in August 1694. This was published during the year 1695 in the Philosophical transactions of the Royal Society of London, Volume 18, page 225. Part of that text can be seen on the Royal Society of London’s website.

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Edward Llwyd’s letter. Source: Royal Society of London

What Llwyd discovers, like many others, is that the source of the problem appeared to be Morfa Bychan (or what is now known as Black Rock Sands) near Criccieth. Surprisingly, it appears that only those living along the coast on the other side of the bay (constituting the Traeth Mawr and Traeth Bach) were affected by the vapour.

‘it is observed to come from a place called Morva Bychan in Caernarvonshire, about Eight or Nine Miles off [over part of the Sea.] That Cattle of all sorts, as Sheep, Goats, Hogs, Cows, and Horses, still dye apace; and that for certain, any great Noise, as Winding of Horns, Drums, &c. does repel it from any House, or Barn, or Stacks of Hay…

Another author David William Pughe, writing in the year 1846 had this to say about the mephitic vapour:

‘In 1694 this neighbourhood unfortunately became celebrated for a phenomena fully as difficult of elucidation as the twisted baldrick above adverted to. I allude to a dense mephitic vapour, that for a period of eight months spread devastation and dismay through the lowlands of Ardudwy. Its appearance was that of a dense sheet of curd – coloured exhalation , progressing with a slow uniform motion across the marshy ground, and which, when ignited, burtn with a pale lambent flame. It generally made its appearance at night-fall, and had its source, if we may credit the current testimony of the sufferers, in Morfa Bychan (Little Marsh) near Crickieth.’ (Source: An historical sketch of Harlech castle and its environs, 1846.)

Noted writers (and visitors to the principality) such as Daniel Defoe, William Bingley, Robert Southey and Samuel Taylor Coleridge, broached upon the matter of this strange phenomenon, and their information was replicated with regularity in many of the nineteenth century’s journals and magazines. As recently as 2005 it was discussed at length in Barmouth’s Advertiser (although I have no sight of the particular article.)

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Despite Llwyd reporting the year of occurrence as being 1694, there are other references that place it during 1692, with one saying it was 1624 (and this quite likely a mistake.) It began at Christmas time in 1693 when the gaseous vapours first made their way across the sea from Morfa Bychan, sited some eight to ten miles away between Porthmadog and Criccieth.

‘It was a livid vapour, or fiery exhalation, which seemed to arise from the sea on the borders of Caernarvonshire. It made its first appearance on the side of a bay, a little after sun set, and from thence spread itself in the most gradual manner, until it had set all the houses in the neighbourhood on fire.’ (Harlech Merionethshire Universal British Directory 1791)

Driving or walking along the miles of magnificent sand at Morfa Bychan today, also known as Black Rock Sands, it’s difficult to imagine how such a peaceful part of the Welsh coastline could have been the source for such a phenomenon whose disastrous consequences were wreaked on the people of Harlech. The mystery of course was what actually was this mephitic gas? So far, no one seems to have a plausible explanation.

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The beach at Morfa Bychan (Black Rock Sands) looking east. Source: Wikipedia.

No doubt the eastern part of the Llŷn Peninsula is the source of the gas that pervaded further round the coastline. Thus its having crossed the bay from Morfa Bychan, this strange vapour caused bales of hay and corn to set ablaze, and barns were burnt to the ground. Horses, sheep and cattle were badly afflicted by it, most ending up dead. Grass became poisoned. Vegetable plots were ruined. It appears that a number of houses were not immune for these self-ignited too. Yet people were not in the least bit affected by this mephitic vapour.

I think the fact people were not in the slightest affected by this mysterious vapour should set alarm bells ringing. Anyhow let’s continue…

One of the really strange aspects of this phenomenon, where ever one reads it, is that people found that the most effective methods of dispelling the vapour was to use trumpets, horns, fire guns (or any other ‘great noise’ as Llwyd puts it.)

That remedy that was offered is something quite unheard of, and it does make one consider whether the phenomenon was real or just a tale of sorts concocted by the locals.

On the other hand if this had indeed been a real phenomenon, it may well have been that the effects of using a trumpet, horn or gun were somewhat exaggerated – the winds may have done the work of blowing the gaseous vapour away. This would make some sense – especially with the usual westerlies which would have in the first instance blown the gas across the bay, and thence drafted it inland away from the populated areas around Harlech.

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Harlech beach, looking towards Morfa Bychan. How did this peaceful location become the victim of a vile gas in 1694? Source: Geograph © Colin Smith licensed for reuse under the Creative Commons Licence.

A strange manner was the ability to appear at the same periods of day or night each time, usually at night either on a Saturday or a Sunday. At all times the gaseous vapour could be seen and it had the apperance of a weak blue-ish flame. Some accounts insist it occured daily, both in the day and at night. Llwyd makes it clear in his letter that its appearances increased as 1694 progressed. However ALL accounts had one thing upon which they agreed – the fires and animal deaths only occured during the night, NEVER during the day. Its just totally bizarre!

The phenomenon lasted around eight months, hence at the time Llwyd wrote his letter, it would have still been present. It seems that the phenomenon mitigated its effects towards the mid-summer of 1694. There’s one thing I’d like to point out – there was NO summer that year! The ‘little ice age’ (or the Maunder minimum) reached a peak in the later part of the Seventeenth century, its worst years being 1690 to 1698. These are recorded as having no summer at all. Could the consistently cold and damp weather have somehow contributed towards the creation of the phenomenon?

There are those who have at least tried to give a serious scientific insight upon what could have happened. One somewhat likely explanation for the cause of the phenomenon is given as follows in the 1852 publication of ‘On the ancient British, Roman and Saxon antiquities and folk-lore of Worcestershire,’ page 469:

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It does at first glance seem a fairly likely explanation. Yet the notion that it was ignited by electricity bears some suspicion. Gaseous vapours concentrated together (say in a closed room) can be ignited by a spark, which is why undetected gas leaks can cause houses to go up with a bang. Out on the sands in wide open air it would have had to have been an extremely concentrated mixture to cause the effects so described. Perhaps some unknown factor rendered the elements in the air far more volatile than usual.

In terms of a modern perspective on the matter, a further explanation was given in New Scientist magazine several years ago. One of the magazine’s readers had submitted a letter querying the Harlech phenomenon of 1694. The magazine’s editors referred to a phenomenon that had occurred at Moirans-en-Montagne in the French Jura mountains, elaborating an explanation that pockets of natural gas had caused the phenomenon.

In its September 1983 issue the magazine examined at length the so called Egryn lights observed off the coast between Harlech and Barmouth in 1904-5. This cause was attributed to visible radiation issuing from the Mochras fault which stretches along the coast between both towns, known as ‘earth-lights.’ Thus some may think the Harlech phenomenon was due to that geological fault also.

Whatever source one reads, or whatever possible explanation is offered, it is clear that the 1693-1694 phenomenon is NOT caused by the Mochras fault, earth lights, or UFOs! Whether it was the decomposition of seaweed, dead marine life, or other unknown substances, it still seems strange when one considers the phenomenon’s almost clockwork regularity and the fact that its disastrous effects only occurred at night. Even the claim that it only happened at night on Saturdays or Sundays strikes one as strange. Nature, on the other hand, does not usually partake in such things on a regular, timetabled basis, except in terms of sunlight, nightfall and planetary motion. Clearly there’s only one absolute certainty which emerges from this unusual tale – and that is no one will ever know what really happened during those months of 1694.

It makes a fascinating story however!


(This post is an updated version of one I wrote a number of years ago.)