Mining museum celebrates 200 years of Davy Lamps

An event is being held to mark 200 years since the Davy Lamp transformed the safety of mining.
Until 1815, open candles were used and ignited frequent methane explosions.
Sir Humphry Davy's invention is thought to have saved as many as 500,000 lives worldwide and is still in use today.
To mark the occasion on Sunday, Bersham Colliery in Wrexham- now a mining museum - is inviting visitors to bring their Davy Lamps and other industrial heirlooms along for identification.
Davy Lamp is a safety mining lamp and work by screening the flame behind a metal mesh, wide enough to let in enough oxygen for combustion, but too fine to allow the flame to flicker beyond the cage.
As well as providing light, it acted as an indicator for the presence of methane - when it would burn with a taller, bluer flame, and of a lack of oxygen, when the lamp would be extinguished.

Alan Jones, chairman of the North Wales Miners Association Trust, said: "Over the last two centuries the Davy Lamp has seen countless tweaks and improvements, like the introduction of a glass window to allow more light, but it's still the same basic principle.
"Although modern miners cap lamp have been introduced into the coal mine today, there is still some men carrying a Davy Lamp, because while more sophisticated electronic monitors can fail, a Davy Lamp will always work."
But the Davy Lamp was not without teething problems.
Initially its introduction to mines actually saw a rise in accidents as miners - and more importantly bosses - felt more confident in working parts of pits which had previously been no-go areas.
As Mr Jones explained, many of the early problems were not so much to do with the lamps themselves, but the way they were used.
"The earliest examples, before the glass window was introduced, emitted very little light from behind the mesh, so miners would frequently unscrew the cover to see what they were doing. Later models had a tamper-proof lock to prevent this.
"Working in damp conditions the mesh would corrode and even a very small break in the mesh could allow the flame to escape and spark an explosion."

Mr Jones said, because of subtle changes over the years, it is possibly to identify roughly where and when a Davy Lamp was made.
"We're not especially interested in valuing them, most are only worth about £50 or £60, but some of the rarest and oldest examples can sell for over £500," he added.
Another of Sir Humphry's inventions could have held the key to the illumination problems as he was also an early pioneer of electric incandescent lighting, although it would take almost another 100 years before electric lights became common in mines.
He also used electrolysis to isolate several new metals such as sodium and calcium for the first time and became an exponent of nitrous oxide or laughing gas as an anaesthetic, so much so he ended up addicted to it.