FUEL. 
is totally consumed. But it cannot be 
made to burn so as to produce a gentle 
heat. If not in considerable quantity, and 
violently heated, it is soon extinguished. 
In using this kind of fuel, it is proper to 
be on our guard against the dangerous 
nature of the burnt air, which arises from 
charcoal of all kinds. Charcoal burns 
without visible smoke. The air arising 
from it appears to the eye as pure and as 
clear as common air. Hence it is much 
used abroad by those who are studious of 
neatness and cleanliness in their apartments. 
But this very circumstance should make 
ns more watcliful against its effects, which 
may prove dangerous, in the highest de- 
gree, before we are aware of it. The air 
arising from common crude fuel is no doubt 
as bad, but the smoke renders it disagree- 
able before it become dangerous. The 
first sensation is a slight sense of weakness ; 
the limbs seem to require a little atten- 
tion, to prevent falling. A slight giddi- 
ness, accompanied by a distinct feeling 
of a flush, or glow in the face and neck. 
Soon after, the person becomes drowsy, 
would sit down, but commonly falls on the 
floor insensible of all about him, and 
breathes strong, snoring as in an apoplexy. 
If the person is alarmed in time, and 
escapes into the open air, he is commonly 
seized with a violent head-ach, which gra- 
dually abates. 
But when the effect is completed, as 
above described, death very soon ensues, 
unless relief be obtained. There is usually 
a foaming at the mouth, a great flush or 
suffusion over the face and neck, and every 
indication of an oppression of the brain, 
by this accumulation of blood. The most 
successful treatment is to take off a quan- 
tity of blood immediately, and throw cold 
water on the head repeatedly. A strong 
stimulus, such as hartshorn, applied to the 
soles of the feet, has also a very good 
effect. 
The fifth and last kind of fuel is wood, 
or fossil coals, in their crude state, which it 
is proper to distinguish from the charcoals 
of the same substances. The difference 
consists in their giving a copious and bright 
flame, when plenty of air is admitted to 
them, in consequence of which they must 
be considered as fuels very different from 
charcoal, and adapted to different purposes. 
See Flame. 
Flaming fuel cannot be managed like 
the charcoals. If little air be admitted, it 
gives no flame, but sooty vapour, and a 
diminution of heat. And if much air 
be admitted to make those vapours break 
out into flame, the heat is too violent. 
These flaming fuels, however, have their 
particular uses, for which the others are far 
less proper. For it is a fact, that flame, 
when produced in great quantity, and 
made to burn violently, by mixing it with 
a proper quantity of fresh air, by driving 
it on the subject, and throwing it into 
whirls and eddies, which mix the air with 
every part of the hot vapour, gives a most 
intense heat. This proceeds from the 
vaporous nature of flame, and the perfect 
miscibility of it with the air. 
As the immediate contact and action of 
air is necessary to the burning of every 
combustible body ; so the air, when pro- 
perly applied, acts, with far greater ad- 
vantage on flame, than on the solid and 
fixed inflammable bodies: for when air 
is applied to these last, it can only act on 
their surface, or the particles of them that 
are outermost; whereas flame being a 
vapour or elastic fluid, the air, by proper 
contrivances, can be intimately mixed with 
it, and made to act on every part of it, 
external and internal, at the same time. 
This great power of flame which is the con- 
quence of this, does not appear when we 
try small quantities of it, and allow it to 
burn quietly, because the air is not in- 
timately mixed with it, but acts only on 
the outside, and the quantity of burning 
matter in the surface of a small flame is 
too small to produce much effect. 
But when flame is produced in large 
quantity, and is properly mixed and agitat- 
ed with air, its power to heat bodies is 
immensely increased. It is therefore pecu- 
liarly proper for heating large quantities 
of matter to a violent degree, especially if 
the contact of solid fuel with such matter 
is inconvenient. Flaming fuel is used for 
this reason in many operations performed 
on large quantities of metal, or metallic 
minerals, in the making of glass, and in the 
baking or burning of all kinds ofearthem 
ware. The potter's kiln is a cylindrical 
cavity, filled from the bottom to the top 
with columns of wares, the only interstices 
are those that are left between the columns ; 
and the flame, when produced in sufficient 
quantity, proves a torrent of liquid fire, 
constantly flowing up through the whole 
of the insterstices, and heats the whole pile 
in an equal manner. 
Flaming fuel is also proper in many 
works or manufactories, in which much fuel 
