Suzanne's Mom's Blog

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“In a 2019 fire, Notre Dame’s spire toppled and pierced its vaulted ceiling. Its lead roof melted into jagged stalactites,” writes Christa Lesté-Lasserre at the journal Science.

How did you spend your Sunday? I took an early walk and watched FaceTime with my husband as Suzanne’s kids hunted for eggs. John sent a picture of his egg-hunters, and in the afternoon we chatted. I also “attended” San Francisco’s Glide Memorial Church via Zoom, but it got hacked, and the church had to turn off the “chat” feature. The music was super, as usual. Then Suzanne sent me a Broadway-style Passover seder meant to raise money for the CDC Foundation’s COVID-19 Emergency Response Fund, and I got a huge kick out of that.

Meanwhile, in Paris, online services were performed at the damaged Notre Dame Cathedral, as you can read at CNN. Reporter Alaa Elassar quotes Paris Archbishop Michel Aupetit: “A year ago, the cathedral was destroyed. Today the country is ravaged by a pandemic. There’s always a message of hope, and this celebration at the heart of the cathedral will be the sign of our hope.”

My post today is about that cathedral.

Christa Lesté-Lasserre writes at the journal Science, “Eight restoration scientists put on hard hats and heavy-duty boots and stepped inside the blackened shell of Notre Dame de Paris, the world’s most famous cathedral. Ten days earlier, a fire had swept through its attic, melted its roof, and sent its spire plunging like an arrow into the heart of the sacred space. Now, it was silent but for the flutter of house sparrows. The space, normally sweet with incense, was acrid with ash and stale smoke. Light beamed through voids in the vaulted stone ceiling, cutting through the gloom and illuminating piles of debris on the marble floor.

“Yet the scientists, called in by France’s Ministry of Culture to inspect the damage and plan a rescue, mostly felt relief — and even hope. Rattan chairs sat in tidy rows, priceless paintings hung undamaged, and, above the altar, a great gold-plated cross loomed over the Pietà, a statue of the virgin Mary cradling the body of Jesus.

“ ‘What matters isn’t the roof and vault so much as the sanctuary they protect,’ says Aline Magnien, director of the Historical Monuments Research Laboratory (LRMH). “The heart of Notre Dame had been saved.”

“On 15 April 2019, an electrical short was the likely spark for a blaze that threatened to burn the 850-year-old cathedral to the ground. Following a protocol developed for just such a disaster, firefighters knew which works of art to rescue and in which order. They knew to keep the water pressure low and to avoid spraying stained glass windows so the cold water wouldn’t shatter the hot glass.

“But even though their efforts averted the worst, the emergency was far from over. More than 200 tons of toxic lead from the roof and spire was unaccounted for. And the damage threatened the delicate balance of forces between the vault and the cathedral’s flying buttresses: The entire building teetered on possible collapse.

“At LRMH, the laboratory tasked with conserving all the nation’s monuments, Magnien and her 22 colleagues apply techniques from geology to metallurgy as they evaluate the condition of Notre Dame’s stone, mortar, glass, paint, and metal. They aim to prevent further damage to the cathedral and to guide engineers in the national effort to restore it. …

“And even as they try to reclaim what was lost, they and others are also taking advantage of a rare scientific opportunity. The cathedral, laid bare to inspection by the fire, is yielding clues to the mysteries of its medieval past. …

“The LRMH researchers work in the former stables of a 17th century chateau in Champssur-Marne, in the eastern suburbs of Paris. … Véronique Vergès-Belmin, a geologist and head of LRMH’s stone division, was sorting cathedral stones until 10 p.m. last night. This morning, she’s the first to unlock the laboratory’s ancient oak door.

“She slips a hazmat suit over her dress clothes and slides on a respirator mask — necessary when dealing with samples contaminated with lead. In the lab’s high-roofed storage hangar — once a garage for the chateau’s carriages — she presents several dozen stones that fell from the cathedral’s vaulted ceiling. Fallen stones hint at the condition of those still in place, which are largely inaccessible. The scientists can’t risk adding their weight to the top of the vault, and debris falling near the holes in the ceiling makes it dangerous to inspect the structure from below. Many of the samples in the lab were retrieved by robots.

“Heat can weaken limestone, and knowing the temperatures endured by these fallen stones can help engineers decide whether they can be reused. Vergès-Belmin has found that the stones’ color can provide clues. At 300°C to 400°C, she says, iron crystals that help knit the limestone together begin to break down, turning the surface red. … ‘Any colored stones or parts should not be reused.’ …

“Philippe Dillmann, an LRMH collaborator and a metal specialist with CNRS, the French national research agency, believes rust from the cathedral’s iron structures can provide similar clues. At increasing temperatures, the microscopic structure of the rust changes. By investigating the cathedral’s nuts and bolts — literally — as well as a ‘chaining’ system of iron bars within and around its walls, Dillmann wants to create a heat map for the nearby stones. He says it’s unknown whether these bars were used in construction and left in place or served as reinforcement. …

“Beyond the physical damage left by the fire is the emotional trauma suffered by thousands of Parisians and others, and CNRS researchers are also investigating this hidden aftermath.

Sylvie Sagnes, a CNRS ethnologist with the Interdisciplinary Institute of Contemporary Anthropology in Paris, is part of a group that will interview tourists, locals, guides, journalists, donors, and church members to analyze the fire’s emotional effect.

“She says people can display a powerful attachment to monuments, parks, and historical sites. When people mobilize to protect heritage, she says, it’s a democratic expression — something French anthropologists studied 30 years ago during a public outcry against planned renovations of a basilica in Toulouse. In the case of Notre Dame, strong feelings are intensifying controversies around its restoration, such as whether to rebuild it exactly as it was.

“ ‘Notre Dame isn’t just any monument,’ she says. ‘After the fire, people remain emotionally implicated.’ ” Over to you, Pierman Sister.

More at Science.

P.S. Do take a look at Andrea Bocelli singing in Milan’s Duomo on Easter, here.

Photo: CNN
A meditation ceremony was arranged at the damaged Notre Dame Cathedral in Paris to celebrate Good Friday 2020.

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