Davy lamp
The respirator was to prevent the inhaling of injurious gases, and to supply the miner with good air; the lamps were constructed to burn in the most inflammable kind of fire-damp without igniting the gas.
A month before Davy presented his design to the Royal Society, Stephenson demonstrated his own lamp to two witnesses by taking it down Killingworth Colliery and holding it in front of a fissure from which firedamp was issuing.
[6][8][a] A local committee of enquiry gathered in support of Stephenson exonerated him, showing that he had been working separately to create the Geordie lamp,[10] and raised a subscription for him of £1,000.
A methane-air flame is extinguished at about 17% oxygen content (which will still support life), so the lamp gave an early indication of an unhealthy atmosphere, allowing the miners to get out before they died of asphyxiation.
Results more satisfactory were not to be wished..."[16] Another correspondent to the paper commented "The Lamp offers absolute security to the miner... With the excellent ventilation of the Whitehaven Collieries and the application of Sir HUMPHRY's valuable instrument, the accidents from the explosion of' (carbureted) 'hydrogene which have occurred (although comparatively few for such extensive works) will by this happy invention be avoided".
Miners still preferred the better illumination from a naked light, and mine regulations insisting that only safety lamps be used[17]: 139 were draconian in principle, but in practice neither observed nor enforced.
Work carried out by a scientific witness and reported by the committee showed that the Davy lamp became unsafe in airflows so low that a Davy lamp carried at normal walking pace against normal airflows in walkways was only safe if provided with a draught shield[20]: 13–17 (not normally fitted), and the committee noted that accidents had happened when the lamp was "in general and careful use; no one survived to tell the tale of how these occurrences took place; conjecture supplied the want of positive knowledge most unsatisfactorily; but incidents are recorded which prove what must follow unreasonable testing of the lamp; and your Committee are constrained to believe that ignorance and a false reliance upon its merits, in cases attended with unwarrantable risks, have led to disastrous consequences"[11]: 131 The "South Shields Committee", a body set up by a public meeting there[21] (in response to an explosion at the St Hilda pit in 1839)[22] to consider the prevention of accidents in mines had shown that mine ventilation in the North-East was generally deficient, with an insufficient supply of fresh air giving every opportunity for explosive mixtures of gas to accumulate.
[24] The Mines Regulation Act 1860 therefore required coal mines to have an adequate amount of ventilation, constantly produced, to dilute and render harmless noxious gases so that work areas were – under ordinary circumstances – in a fit state to be worked (areas where a normally safe atmosphere could not be ensured were to be fenced off "as far as possible"): it also required safety lamps to be examined and securely locked by a duly authorized person before use.
[30] A replica of a Davy lamp is located in front of the ticket office at the Stadium of Light (Sunderland AFC) which is built on a former coal mine.
[32] In 2016, the Royal Institution of Great Britain, where the Davy lamp prototype is displayed, decided to have the invention 3D scanned, reverse engineered and presented to the museum visitors in a more accessible digital format via a virtual reality cabinet.
At first sight it appears to be a traditional display cabinet but has a touch screen with various options for visitors to view and reference the virtual exhibits inside.
