Flicking through a 1940's children's book last night I came across the following picture.
🔗Personal-Album-988-Image-90127[linkphoto]Personal-Album-988-Image-90127[/linkphoto][/link]

Now whilst its clear that Sir Humph himself is holding an approximation of a Davy Lamp, I've not seen one of the devices the child is holding before.

Does anyone have one or a modern picture? :flowers:

Not clear whether that means for lighting the lamp or lighting the mine before Mr Davy rocked up.

Seems to have sparks coming out of it, which pretty much negates the whole point of a safety lamp if you have to take that with you.

oh god....its a spark mill or similar, seen it referred to as such in NCB texts believe it or not as a light source..cant imagine anything more dangerous in coal mines. dont honestly know if there are any extant mills you could get a picture of!

Indeedy.

A Spedding Steel Mill apparently.

Invented by Carlisle Spedding, Whitehaven, England circa 1730s

🔗Personal-Album-859-Image-90128[linkphoto]Personal-Album-859-Image-90128[/linkphoto][/link]

the modern equivalent would be an angle grinder Chris! :lol:

dont honestly know if there are any extant mills you could get a picture of!

It's easy to see why you might think that! :lol:

It'd be interesting to are one in use. Preferably not in a coal mine however...

Should be fairly easy to make one.
Just looks like a spinning metal disk and a flint

Maybe they used it to get the padlock off the gate.......
:lol:

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A quick and crude test with an empty old style unshielded cigarette lighter in a dark room suggests the light output might be quite good, better than 2 or 3 candles for a guess.

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can see what they were getting at, been working late on some job outside the workshop with a disc cutter/grinder and it does light the place up. not pleasant if the sparks are directed up at you though (like the lttle chap in the picture)

Friend of mine has a reproduction Spedding Mill and the light is actually very good ... I would say alot brighter than a Davy type lamp.
Obvious disadvantage is its a full time occupation working the mill which is, I suppose, why it's a child's job.
I've heard it said the sparks change colour with increasing amount of methane in the air but never felt inclined to test it.

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Sadly the illustration helps to perpetuate the myth that miners carried canaries with them all the time.......

Les

There is a replica Spedding mill on display at King Edward Mine.

I seem to recall that an American chappie gave a lecture of Spedding mills at the Coniston NAMHO conference in 2004/5 (ish)

Seems more likely to be an early gas detector, send a kid in there spinning one of these, if he explodes, don't send valuable miners in there!!.

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A few nineteenth century Spedding Steel Mills are in coal mining museums - they seem to show sufficient wear and tear to indicate that they were genuinely used underground and for considerably more than short trials.

E.Thomas & Williams, the Welsh flame safety lamp manufacturers, had a few replicas made for sale around the late 1980s. (They also made replica Davy and Clanny lamps which sold better than steel mills).

The theory underlying the steel mill was that the sparks given off were 'colder' than a naked flame and less likely to ignite methane-air mixtures.

In view of the intermittent light given and the not inconsiderable cost of employing a boy to turn the mill, the genuine used examples that survive must have been used in gassy places where a naked flame was too dangerous. I have wondered whether they were resorted to in operations such as driving crucial ventilation headings where the inconvenience and expense could be justified by the necessity of completing the work. I have never seen contemprary accounts of their use which suggests that they were not much used and not often resorted to.

There is a contemporary account by Spedding himself of its use in the sinking of Saltom Pit.

In a paper submitted to the Royal Society (Vol. 38, 1733-4) an account is given of meeting a blower late in 1730 which "burn'd a full Yard in Diameter and about three Yards high. ........After this no Candles were suffered to come near it." The paper also states (incorrectly as it turned out) "It is to be observed that this sort of Vapour, or damp Air, will not take Fire except by Flame; Sparks will not affect it, and for that Reason it is frequent to use Flint and Steel in Places affected with this sort of Damp, which will give a glimmering Light, that is a great Help to the Workmen in difficult Cases."

At the time of writing, Aug. 1733, the gas was still issuing undiminished in strength and quantity after 27 months although it was now contained and piped ("2 inches square")to the surface. Many years later this was the same horizon where we had the greatest gas flows from our methane drainage boreholes 3- 5 miles to the west.

(Perhaps the nearest we got to seeing how it worked was when the shearer picks hiit the sand/siltstone roof - and the fallacy of "cold" sparks on the occasions when they ignited a bit of gas).

There is a replica Spedding Steel Mill on display in the Midlands at present it is part of the current exhibition at the Ironbridge George Museum.
http://www.ironbridge.org.uk/collections/current-exhibition/ 
The one on display is nearly identical to christwigg's photo, the difference being the absence of the cup-like component where the flint contacts the rotating wheel.

The exhibition is on until the end of the year. Worth a glance if you are nearby, and its FREE.

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There is also a replica at Snailbeach mine in the visitor centre. :smartass:

There is a replica Spedding Steel Mill on display in the Midlands at present it is part of the current exhibition at the Ironbridge George Museum.
http://www.ironbridge.org.uk/collections/current-exhibition/ 
The one on display is nearly identical to christwigg's photo, the difference being the absence of the cup-like component where the flint contacts the rotating wheel.

The exhibition is on until the end of the year. Worth a glance if you are nearby, and its FREE.

Don't think it is a "cup-like component" I think it looks more like a split nodule.

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Don't think it is a "cup-like component" I think it looks more like a split nodule.

Having had another look at the photo you could well be right. :thumbup:

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