KOLKATA: The Angel of Victory poised gracefully atop Victoria Memorial Hall is not just a glamourous weather vane . For a century now, the fairy with the trumpet has been protecting the monument from lightning strikes. Why it didn’t neutralise the bolt that struck the ground on Friday afternoon, when a visitor was killed and multiple others were injured, is a mystery. But Victoria authorities vouched the Angel had saved the museum and its visitors on numerous occasions earlier.“The Angel is the most glamourous lightning arrester in not only Kolkata but also whole of India. At a height of nearly 61m, it was the tallest structure in the city when built, towering over the 48-metre Ochterlony Monument that was later renamed Shaheed Minar. Hence, it attracted lightning often. Though there are taller buildings along Chowringhee now, Victoria Memorial Hall (VMH) still stands tall amid the Maidan’s greenery and the fairy continues to sustain several lightning strikes each monsoon ,” said VMH curator Jayanta Sengupta.The 3.5-tonne bronze statue stands on a 3-tonne base with ball bearings and a pod containing mercury. A thick copper rod runs down to the ground, providing the earthing. Mantu Das, who tops up the mercury every week, says the liquid metal is crucial to prevent the tremendous heat during a lightning strike from welding the ball bearings that help the fairy rotate when a stiff wind blows. While a wind at 15kmph was enough to make it swing earlier, now it does so only when the wind blows at 18kmph-20kmph. “The fairy had stopped rotating twice, once around 1978 and again, around 1992. In the first instance, the mercury had gone missing from the case, causing the bearing to ham. In the second instance, spot welding of the ball bearing had occurred after a lightning strike. This was due to theft of the copper rod that provides the earthing. Luckily, the VMH was not damaged,” Das said.The rotation of the Angel is critical to Victoria Memorial. When the rotation had stopped in the 1970s, engineers discovered that the fairy and its base had tilted three-quarters of an inch, putting tremendous strain on the dome. It was a miracle that the dome had not cracked.The fairy had been designed by English sculptor Lindsay Clarke and cast into bronze by George Mancini. The final sculpture was shipped from Cheltenham, England, to India in 1920. While the Angel is alluring enough to attract most lightning strikes in the vicinity, there have been odd instances of lightning avoiding its embrace. Last year, a bolt had struck a pond. Three years ago, another bolt had struck a dead tree, splitting its trunk. “There are 2,800 trees on the ground. Nearly all of them are in clusters. The tree that was struck was a solitary one and took the hit. Perhaps, more trees would have been struck by lightning had the Angel not been around,” Sengupta added.