Colored sparks

From: 	Gary Lau  10-Dec-1997 1244[SMTP:lau-at-hdecad.ENET.dec-dot-com]
Sent: 	Wednesday, December 10, 1997 10:51 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Colored sparks

Last night I placed a small wad of paper towel, soaked in water, and
thickly covered with table salt on my torroid such that this would
constitute a breakout point.  The streamer that originated from this
point was beautiful - BRIGHT sodium-yellow for about the first foot of
arc, then fading to the usual blue-violet.  Try it!

I'm anxious to try salts of other metals - copper, barium, and  strontium
come to mind.  Two things though.  As the arc vaporized the salt, it was
re-deposited on the surface of the torroid, so that even after removing
the salty wad, sparks leaving the torroid were somewhat yellow (perhaps a
concern for purists, may also be corrosive to the aluminum tape).  Also,
while NaCl vapors and dust are harmless, other salts may not be.

Gary Lau
Waltham, MA USA