The message
from Martin Brown contains these words:

It won't burn particularly well, but if you can get it loaded with
enough potassium nitrate and alight it will continue to smoulder if it
ever gets dry enough. I tried this with an old dead 2' diameter pear
tree stump about a decade ago. The effect was that it would not burn
because ground was far too wet even on the driest summer days.

Saltpetre *IS* potassium nitrate.

--
Rusty Hinge http://www.users.zetnet.co.uk/hi-fi/tqt.htm

Dark thoughts about the Wumpus concerto played with piano,
iron bar and two sledge hammers. (Wumpus, 15/11/03)