Sunday, 15 July 2012

The Real Olympic Flame

by Jeremy Thomas

Princess Anne carries the Olympic Flame
As the Olympic torch relay has been in Hampshire this week, and passes through Portsmouth today, many people in the area will be excited by seeing the flame pass by, burning atop the magic, golden torches held by each of the relay runners. Something that caught my attention in a recent TV news bulletin though, was the escort runner who popped out of the accompanying bus at one stage, carrying an object I am very familiar with, one that has sat on the fireplace in my mother’s living room since the near-total demise of the Welsh coal industry in the 1980s. This was a miner’s Davy Lamp, selected for its reliability and safety to keep the Olympic flame burning during the relay, against all odds, since the Sydney Olympics in 2000. It seems that, if the torch flames do go out, the shiny, gold Davy lamp is produced from the bus to relight it, thus ensuring the continuity of the original flame lit on Mount Olympus several weeks ago.
So, why use a Davy lamp, invented in 1815 to save the lives of coal miners, to carry the modern Olympic Flame? Surely there must be a high-tech electronic method these days? Perhaps even  a ‘flame app’ to replace the real one? The remarkable thing is that there is still no better or safer way, so safe in fact that the burning lamp can even be carried, in a suitable seat cradle, on passenger aircraft en route from Greece to the Olympic host nation.  How did Sir Humphry Davy achieve such a successful design, nearly two hundred years ago, a design that has changed very little ever since?
Well, he did so mainly through his knowledge of Chemistry and Physics, combined with a working appreciation of Victorian mining, perhaps gained from his upbringing in the Cornish town of Penzance, surrounded by the mineral mining industry of the area. Cornish tin miners, though, did not face one of the most devastating hazards of the coal mines in Wales and other parts of England. This was ‘firedamp’, an accumulation of methane gas which exploded violently, especially in the dusty atmosphere of the mine workings, when exposed to the naked flames used as lamps by miners in those days. Through experimentation, and building on the less practical designs of other people, Davy came up with a beautifully simple solution.

By surrounding the lamp flame with a thin, metal, gauze cylinder he showed that the heat from the flame was dissipated quickly through the gauze, so that any explosive gas on the outside did not reach its ignition temperature.  The lamp could also be used safely to test for the presence of methane, because the small quantities inside the lamp made the flame burn more brightly, with a bluish hue like the gas in a domestic cooker. The flame also went out in the presence of another mining hazard, blackdamp, consisting largely of carbon dioxide which is heavier than air and so collects at low levels, suffocating miners if they don’t realise it’s there.
My mother’s Davy lamp is the genuine article, as many of them were available for sale in South Wales and other mining areas as the coal industry went into decline. Whether it was official Coal Board policy to sell them I have never been quite sure. The base is made of tarnished brass, but the sides and cap are battered and painted black as all real, working lamps were. The Olympic lamp is obviously kept nicely polished and rests in its cradle, carrying the inextinguishable flame in comfort on its journey around the country. This particular lamp was proudly manufactured by the Protector Lamp company of Eccles, Manchester, who still manufacture Davy lamps for mine safety and other purposes. Two hundred years on, it is a tribute to the scientifc and technical skills of Sir Humphry Davy that his elegant design not only saved the lives of countless workers in the mining industry, but that it is still the most practical way to carry a flame safely wherever it needs to go!

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