128 Morey on Heat and Light. 
darker and thicker :* and as the bark of this wood appears 
to be as indestructible by time as charcoal, 1 know not why 
this too may not be useful for many purposes. Nothing 
ean burn better than the vapor of this bark, but it requires 
a mueh higher temperature to evaporate it; and as it is re- 
plenished by nature when taken from growing trees, by 
cultivating those trees for firewood, we at the same time are 
reaping an abundance of an excellent substance for light. 
When the piece of gun barrel mentioned is used, it makes 
the chief of the grate, the flame and the smoke, when there 
is any, and the air also, enter about two inches above and 
pass down through the grate. - The bulk of the fame, when 
the steam is suffered to flow in, is nearly as three to one, 
and much whiter. A singular circumstance often attended 
this mode of proceeding, when it was employed in burning 
rosin and water. Instead of ashes I found potash only, ov 
little else. So much was this the fact, that with a particular 
kind of coal, the grate would become, in about two hours, 
so choaked or coated, as obliged me to remove the fire. 
I give the result, (very nearly,) of experiments made on 
the evenings of the 22d, 23d, and 24th of March, with a 
lamp weighing two pounds and two ounces, the inner cylin- 
der of which is of two inches diameter at the top, and about 
two and a quarter at the bottom, and six long, besides about 
one inch tunnelled out at the bottom of the outer cylinder, 
which is seven and a half inches long, leaving a space be- 
tween the two about three-fourths of an inch in the clear. 
Which space will hold nearly one pound of the wood, and 
the inner one about two ounces of coal; the residue of the 
coal is contaimed in a tin plate tube of the same size as the 
inner cylinder, and extended above it, with a register at the 
top, which is removed when the coal is put in, A tube 
leads the vapor up by the side of this to the top, where it is 
let out to burn in the manner gas would be, taking care to 
have a high temperature preserved the whole length. Into 
this lamp, the 22d inst. at a quarter past six o’clock, I put 
thirteen ounces of fat wood, and three ounces of charcoal, 
having previously dropped down three or four pieces of coal 
that were burning. It burned nearly regularly for three 
* Than what? We presume than the liauor before mentioned as being 
distilled trom wood —£dil 
