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From: campbelr@hpdsd.UUCP (Bob Campbell)
Newsgroups: sci.physics
Subject: Re: coal mines and candles
Message-ID: <780001@hpdsd.UUCP>
Date: Tue, 11-Nov-86 17:45:00 EST
Article-I.D.: hpdsd.780001
Posted: Tue Nov 11 17:45:00 1986
Date-Received: Sun, 16-Nov-86 01:39:51 EST
References: <238@sri-arpa.ARPA>
Lines: 14

Yes, the candle works.  If you are ever in Chicago, visit the Museum of
Science and Industry.  Among the exhibits there is a "working" coal mine
that you can take tours through.

At the end they demonstrate the miners lamp.  I recall it had something
other than a candle in it, but all that matters is a flame.  If the wire
mesh around the candle is intact, the flame will flash but will not pass
the screen.  If even a tiny hole exists in the mesh, the mine itself will
explode.  There are boxes at the top of the shaft to test the lamps before
entering the mine.  I believe that they are still used to test for gas
by mine engineers, but the average miner uses electric lights.

Bob Campbell - Hewlett Packard Information Technology Group
	       hpdsd!campbelr@hplabs.HP.COM