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From: JOHNSON%nuhub.acs.northeastern.edu@CSNET-RELAY.ARPA
Newsgroups: sci.physics
Subject: coal mines and candles
Message-ID: <238@sri-arpa.ARPA>
Date: Tue, 4-Nov-86 07:58:00 EST
Article-I.D.: sri-arpa.238
Posted: Tue Nov  4 07:58:00 1986
Date-Received: Sat, 8-Nov-86 05:34:00 EST
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From:  "I am only an egg." <JOHNSON%nuhub.acs.northeastern.edu@CSNET-RELAY.ARPA>

     At one time I was informed that early coal miners used candles on 
their helmets to provide light in the mines.  This would cause an 
explosion now and them because of coal gas build-up.  Someone 
discovered that by putting a metal cage around the flame, the candle 
could be safely used in the mine.

     Does anybody know whether or not this is true, who discovered it 
and why it works?

Chris Johnson
Northeastern University