82 Properties of Wood Ashes. 
laid upon a board. In two minutes the “fire went out” of both 
these coals. ; 
» 2. A wooden pill-box of the largest size was filled with sifted 
ashes, and an oak coal weighing seven grains was barely buried 
in them. In thirty five minutes the box was very warm all over; 
and at this time I surrounded it with cold ashes. In ‘twenty 
minutes more, the ashes within and immediately around the box 
were uncomfortably hot. yg : 
3. [renewed the second experiment, with the exception of not 
wholly covering the box. The edge was left exposed, to ascer- 
tain whether it would not act as a vent to the accumulating ca- 
loric. In half an hour I examined the coal, and found it extinct 
and the ashes cold. The coal in this case was of beech. 
4. This beech coal lighted at one corner, was placed on a cone 
of sifted ashes, as in the first experiment, and in twenty minutes 
it was thoroughly ignited. I now pressed a cylinder of paste- 
board perpendicularly into the ashes, so as to include the coal and 
most of the heated ashes. 'The upper edge of the cylinder was 
left uncovered. I did not examine: the coal-for an hour ; it was 
at that time not consumed but dead, and the ashes were entirely 
5. [built a cone of a quart of pale ashes, and deposited eight 
or ten dead coals some distance apart, near the base and re- 
mote from the surface; at the apex I buried a live coal as before. 
In three quarters of an hour, stiff paper or a splinter of wood 
thrust into the centre of the heap took fire ; and on demolishing 
the pile, I found that the heat had descended to the coals below, 
and ignited them ; indeed they were partially consumed, and the 
whole interior of the base of the cone was extremely hot. 
6. A wooden box ten inches deep and eleven inches square; 
was filled with unsifted ashes as cold as an exposure of several 
weeks in winter could make them. A pint. of hot ashes was 
thrown upon the middle of the surface and left uncovered. In 
eight hours all the central portion of the ashes was hot enough 
to fire wood thrust into it, and two sides of the box were inca- 
lescent. In twenty three hours, the bottom of the box was quite 
becoming cool. A stick plunged to the bottom of the ashes, was 
drawn out ignited or burnt at the end, but not even charred above 
ra 
