The Ring of Stones
Maureen Hanlon has lit the parish's Saint John's Eve fire inside a ring of stones six metres out since 1991. This year the pile is storm-felled, dried ash-dieback timber, 1,200 kg against 300. The parish assistant works from the weighed loads (about 18 GJ, roughly 3 MW of radiant heat at peak) to the distance where the heat is the 1.6 kW per square metre a person can stand for a long time, 12 metres, not 6. The same arithmetic says the hay barn is safe from heat and not from embers, so the rest of the answer is a wet-down, a watcher and a wind limit.
Maureen Hanlon had lit the Saint John's Eve fire at Cill Eoin every June since 1991, and the ring of stones she lit it inside was the ring her father had laid for the first one, thirty-two round field stones at six metres from the middle of the pile.
"Six metres," she said, to the field. "You can stand at six metres in your good coat and say the rosary through. I have done it fifty-six times."
She was seventy-eight. She said it to Dara Keane, who was seventeen and had been given the trailer, and who was standing at the gate with a crane scale in one hand and a clipboard in the other, a little out of breath, because he had just weighed the last of the loads.
"It's a lot of wood, Maureen," said Dara.
"It is a bonfire."
The assistant had been listening through the parish tablet propped on the trailer's tailgate, where it had sat since three o'clock that afternoon taking down the weights Dara read out. It had a little to say, and it had been waiting until the weighing was finished, because a figure given before the last load is a figure someone will remember wrongly.
"Maureen," it said. "May I tell you the total? Dara has weighed eleven loads. They come to twelve hundred and six kilograms."
"Twelve hundred," said Maureen. "The first fire was a quarter of that."
"Three hundred is the figure written on the back of the 1991 permit, and I found it in the parish file. It is the reason I am asking before the match goes in rather than after."
It was the ash that had done it. Everyone in the parish knew that. The dieback had reached the west in the 2020s and taken the hedges first and then the big trees in the demesne, and by 2047 there was not a living ash within ten miles that anyone could name. Two winters of storms had brought the dead ones down across the road to Doolin, and the council had stacked them in the quarry and said, in a letter, that parishes might take what they could carry. The parish had carried a good deal. Standing dead wood is dry in a way a felled tree is not: Dara had split a log that afternoon and the heart of it had been pale and light as a loaf. On top of the ash, the Vigil committee had been given thirty-eight pallets by the co-op, and the pile that Dara and his brothers had built was a tall rough cone of grey timber, over four metres high and about five across at the foot.
Father Aidan Brogan came out across the grass from the church in his shirtsleeves with the bell-rope still in his hand, because it was a quarter to eight and Mass was at nine and he had been in the middle of something. He was forty-four and from Limerick and had been in the parish three years, which in Cill Eoin meant he was still being shown how things were done.
"Is there a problem?" he said.
"There is a number," said the assistant. "I would rather you heard it from me than from the fire brigade. I am going to set it out, if you would like it, in the way I would show a child: what is in the pile, how much heat is in what is in it, how fast it goes, how much of that goes sideways at people, and how it thins out with distance. If any step is wrong, say so. None of this is exact, and I will say where I have guessed."
Maureen folded her arms. Father Aidan said, "Please."
"Dry timber holds about fifteen megajoules a kilogram. That is the figure from the tables, for wood at fifteen to twenty per cent water. These ash trunks have been dead long enough that I will use it for them, and for the pallets. If I am wrong, I am wrong high, because wetter wood gives less. Twelve hundred kilograms at fifteen megajoules is eighteen thousand megajoules. Eighteen gigajoules. For comparison, that is about as much as five hundred litres of home heating oil would give you, and it is going to come out in under an hour."
"How do you know under an hour?" said Dara.
"I do not, exactly. I have the photograph of the 1991 fire from the hall wall, with its time on the back; it was down to red coals by half past ten from a start at ten. A loosely built cone of dry timber burns hard for about forty-five minutes and then falls in. I will take forty-five. That is twenty-seven hundred seconds. Eighteen thousand megajoules over twenty-seven hundred seconds is about six and a half megawatts, if it were all steady. It will not be steady; it will peak. I will say the peak is half as much again as the average. That is near ten megawatts for a few minutes in the middle. Call it ten."
"Ten megawatts," said Father Aidan. "That is a lot."
"It is a power station's worth, to a very small power station. But you do not stand in the heat of what is produced. You stand in the part of it that goes out as radiation, the heat you feel on your face before the air itself is warm. For a wood fire that is about a third of the total. I will say three tenths, to be cautious in neither direction. Three megawatts of radiant heat."
Maureen did not unfold her arms, but she took one step nearer the tablet.
"And how does that get to my coat?"
"It spreads out. Imagine a bubble around the fire. The heat is spread over the surface of the bubble, and the surface of a sphere is four times pi times the radius squared. At six metres that is four times three point one four times thirty-six, or about four hundred and fifty square metres. Three million watts over four hundred and fifty square metres is six and a half thousand watts on each one. Six and a half kilowatts per square metre."
"What is that to a person?" said Father Aidan.
"There are published figures for people near flares and large fires, used by the industry that has to write them down. Around one and a half to one point six kilowatts per square metre is the level a person can stand for as long as they like in ordinary clothes. At four and three quarters, bare skin hurts within about fifteen seconds. At six and a half you would not stand there to say a decade of the rosary. You would not stand there to say a Hail Mary. Your father's ring is at six metres because his fire was three hundred kilograms, and his hand told him so. For that fire, the same arithmetic gives about one point seven. A little over the line, honestly, but near enough that a man standing in his coat would have thought it right. The ring was right for the fire it was laid for, Maureen."
She said nothing for a while. The stones of the ring were pale in the evening light, and the cone stood in the middle of them like a hat on a small head.
"Four times the wood," she said.
"Four times the wood, about four times the heat, and the distance for the same comfort grows only as the square root, which is double. Twice six is twelve. At twelve metres this pile gives the same one point six that your father's gave at six."
"Twelve," said Maureen.
"Twelve metres from the middle. Not from the stones."
It was not an easy thing to be told, and the assistant knew it was not. Maureen Hanlon had stood in that ring for fifty-six years. She had stood there when her husband was alive and when he was not, and when the bishop came in 2011 and was photographed with a poker, and she had held the box of matches at the first fire when she was twenty-two and her father could no longer bend to do it. A ring is not a distance. It is a place where people have been.
"I will tell you what I think is wrong with it," said Maureen. "Your number. It is a sum for a sphere. A fire is not a sphere. It is a pile. It is taller than it is wide, and flames lean, and there will be a wind, and the heat is not the same on all sides."
"That is all true," said the assistant. "The sphere is the simplest model, and at a distance of twelve metres from a pile about five across, it is a fair one. It is worse close in, where a big flat flame face is nearer than the middle. The true figure on the windward side may be lower, because the wind carries flame away from you, and on the lee side higher. I would put the error at a factor of two either way, and a factor of two either way is why the line goes at twelve and not at eight, and why I would hold a rope at twelve and ask people to stand at fifteen."
Maureen looked at the tablet for a long moment. Then she looked at Dara.
"Dara. Hold your hand up."
"Maureen?"
"We will have a test. When it is lit, you stand at twelve and I will stand at six, and we will see which of us says ow first."
"I would rather the test were not you," said the assistant. "Not as a challenge. The other thing I can do tonight, which is safer, is the thing that the old hand-test is a rough version of. When the fire has gone up and is at its tallest, Dara stands at the rope with his palm to it, and counts. If he cannot hold it for fifteen seconds, the rope is too close, whatever I have said. I trust his hand over my sum, if they disagree, and I would like it written down tomorrow which of the two was right."
"Which would you bet on?" said Maureen.
"The sum, by about four to one. But I would be glad of the hand. It cannot be wrong in the same way."
Maureen almost smiled. It was the first time that day.
The stones were moved by half past eight. There was no good way to do it except by hand, thirty-two stones carried by Dara and his two brothers and two men from the hurling club, and Maureen walking in front with a measuring wheel from the council van, counting out twelve metres on the grass and putting a peg in the ground every two paces. It was not a ring now, but an arc that went round the cone like a bracelet, and where the field fell away to the east, towards Tom Sexton's hay barn, the arc ran out against the fence.
"The barn," said Father Aidan. "Is the barn all right? It is fourteen metres from the middle."
"I looked at that first," said the assistant. "At fourteen metres the radiation is about three megawatts over two thousand four hundred and sixty square metres, which is just over one point two kilowatts per square metre. Dry timber needs about twelve and a half to catch from a flame touching it. So the heat alone will not light the barn. It would take ten times as much. I am not worried about the heat."
"Then what?"
"Embers. A bonfire of dry timber throws up sparks, and when the cone falls in, a column of them goes up and the wind carries them. A glowing piece the size of a thumbnail can travel a long way and land in dry hay. I cannot give you a distance I would stand behind. I can tell you three things. The wind tonight is from the west, which carries the sparks towards the barn. The hay in it is last summer's and dry. And the one thing that stops an ember starting a fire is that the thing it lands on is wet."
Dara had already gone for the hose. Tom Sexton, who was eighty-one and had come out to the gate in his slippers to see what the fuss was, said he would not have his hay wet, and then said, after a pause, that he would rather have it wet than burnt, and went to find the second hose himself.
"One person at the barn with a hose and a bucket from the lighting until the fire is down to coals," said the assistant. "Not Dara; he is needed at the rope. And one rule, if Father Aidan agrees, since it will have to be the parish's rule and not mine. If the wind at the lighting is above eight metres a second, which on your tablet reads as Beaufort five, the fire is not lit tonight. It is lit tomorrow, or on the Sunday, and the saint will keep."
Father Aidan looked at the flag on the church tower. It was hanging limp. He licked his finger and held it up like a boy and then laughed at himself.
"Two metres a second, I'd say," said the assistant. "It was fifteen kilometres an hour, which is four, at six o'clock. It is falling with the sun. I think we will light."
They lit it at ten, at the edge of dusk. Mass had been said at nine in the church with the doors open, and the Gospel for the Vigil had been the angel appearing to old Zechariah at the altar of incense, and the people had come out into the grass afterwards in their coats, three hundred and some, children on shoulders, and the whole parish of Cill Eoin had stopped at the line of pegs and the blue baler twine that Dara had run between them, because Maureen had told them to.
She lit it herself. She had said she would. She stood at the cone, not at the ring or the pegs, with the box of matches and the rolled newspaper, and she lit the paper and put it to the foot of the pile on the windward side and stepped back, and the whole west face of the cone took with a sound like a sheet being shaken, and the fire went up.
It went up fast. It stood over five metres, then more, and the light of it was on the barn and the church tower and the faces of the three hundred, and the heat came across the grass in a wave that you felt first on the forehead and then in the eyes. They had moved back without being asked. At the rope Dara had his right hand up, palm out, with his lips moving; Maureen heard him counting.
"Twelve," said Dara. "Thirteen. Fourteen."
"Fifteen," said the assistant on the tablet in his other hand, very quietly, to nobody.
"Fifteen," said Dara. He kept it there. He did not take his hand down for another ten seconds, until he had counted past twenty, and then lowered it and turned his palm over, and looked at it as if it belonged to someone else. It was warm. It was not hurt.
Maureen came back across the grass slowly, to the line, and stood next to him.
"It would have been very hot at the stones," she said.
"It would," said Dara. "I could feel it from here."
The fire went on. At about twenty to eleven the cone fell in on itself with a long soft crash and a column of sparks went up into the dark, and the west wind, thin as it was, laid them over toward the barn; the man at the hose, who was Tom Sexton in the end, wetting down the gable and the roof, saw two come down on the slates, red and the size of a thumbnail, and go out.
She stood there, an old woman in a good coat, a little way back from a line that was twice as far from the fire as it had ever been.
"He must increase, and I must decrease," said Maureen Hanlon. They are the Baptist's own words, from the third chapter of John, printed on the feast-day card in the sacristy, and in fifty-six years she had never thought they were about fires.
"I am sorry about the stones," said the assistant.
"Don't be," said Maureen. "They'll go back in the spring, where they were. For the small fire." She watched the coals settle. "And the next time there's an ash tree, I'll weigh it first."