Methane Explosions were common in British Coal Mines of the Industrial Revolution times.
Coal Workers either worked completely in the dark or mostly used naked candles
For those interested in reading some history of how the Davy Flame Safety Lamp was invented.
Despite common perceptions the Davy Lamp was not invented as a gas detection device as such.
Davy designed it as a working light for the coal miners in methane concentrations up to lower explosive limit.
The higher the concentration up to the Lower explosive limit the brighter the flame.
When an explosive mixture enters the lamp, the resulting explosion within the lamp is not propogated to the outside atmosphere and the lamp goes out after the explsoion in the lamp.
As Davy notes that then allows the Coal Miner to safely withdraw himself.
He did this with no modern scientific instruments in a matter of 2 to 3 weeks
There is 26 pages including the cover page. I have also added a one page definition and conversion of parts into percentages.
Also lays out the principal for flame prrof enclosures now used on flame proof electrical equipment
Davy invention of the flame safety lamp is only one of his discoveries.
Davy is best remembered today for isolating, by using electricity, a series of elements for the first time: potassium and sodium in 1807 and calcium, strontium, barium, magnesium and boron the following year, as well as discovering the elemental nature of chlorine and iodine. Davy also studied the forces involved in these separations, inventing the new field of electrochemistry.
In 1799, he experimented with nitrous oxide and was astonished at how it made him laugh, so he nicknamed it “laughing gas” and wrote about its potential anaesthetic properties in relieving pain during surgery.He also invented and a very early form of arc lamp.
I have included modern names for the gases he names for ease of reading
AZOTE is Nitrogen
CARBONIC ACID is Carbon Monoxide
Sulphurated Hydrogene is Hydrogen
Firedamp is Methane
Page 6 identifies that methane is made up of one atom Carbon and 4 hydrogen CH4
Page 6 Parts converted to Percentages
1:1 = 50% CH4 – Burnt but did not explode
2:1 = 33% CH4 – Burnt but did not explode
3:1 = 25% CH4 – Burnt but did not explode
4:1 = 20% CH4 – Flame descends through mixture
6:1 = 14% CH4 – Flame descends and starts to whistle.
8:1 = 11% CH4 – Rather a loud sound
10:1 = 9% CH4
11:1 = 8% CH4 – Violence of combustion starts to decrease.
12:1 = 7.5% CH4
13:1 = 7% CH4
14:1 = 6% CH4
15:1 = 6% CH4
30:1 = 3% CH4
Modern Generally accepted quoted percentages for methane
Upper explosive Limit approx. 15%
Most Explosive Concentration 9.5%
Most Flammable Concentration 7.5%
Lower Explosive Limit 5%