7: | FUEL. 
claffes ; the firft comprehends the fipid inflammable bodies.; 
the fecond, peat orturf; the t coal of wood; the 
_ hare charred ; and the fifth, wood, or pit-c -coal, 
e ftate, and capable of yielding a copious and 
‘af ewmeies are confidered as diftin& from the 
t ey are capa 
‘Is ‘fe fficien he fpecies which oe to this clafs are al- 
dca ‘different c 
The firft of thefe, alcohol, w hen pure and free of water, 
is as convenient and manageable a fuel f 
derate or gentle heats as can be defired. 
fey cleans free from any kind o 
be made to burn flower er fafter, and 
or producing mo- 
Its Hame is per- 
oot 3 it can gee 
to produce lets 
more heat, = prea the _ or number of the ao 
upon which it bur ; for as thefe are fed with 
: in a proper ae es continue to yield flam 
i: e of 
° 
precifely the fame ftrength. he cotton, or other materia 
on- 
is not fcorched or 
fumed in the leait, becaufe the {pirit with which it is con- 
dtantl foaked is incapable of becoming hotter than 174’, 
Heecahelts which is ohn below the heat of ices 
rom it whichis 
atile, it d 
lities ages only to a fpirit that is very pure. 
contrary, it be weak, an ain water, the 
lefs volatile, ay not evaporate fo faft fro ie 1 as the 
more fpirituous part; and the wick becomes, after fome 
time, fo mueh foaked with water that it does not imbike the 
le properly. The flame becomes much weaker, or is al- 
together extingithe, When alcohol is ufed as a fuel, 
therefore, it Ses to be made as flrong, or frce Gon 
water, as po 
Oil, although. fluid like pt of ha and capable of 
is not fo convenient in many 
“anit foot ; an this. applying 
veffel expofed to it 
ereafing in thicknefs, forms, by degrees, a foft and ae 
medium, throagh which heat is not fo freely and quickly 
tranfmitted. This was obferved by Mufchenbroeck in his ex- 
periments upon t the expanfions of metalline rods heated by 
At is true wean prevent this entirely, by ufing very 
e number, if neceffary, to 
oq 
ae 
° 
2m 
‘Oo 
> 
Oe 
‘o 
ar 
oe 
‘0 
z 
‘pe 
a) 
Sco 
4 
Qu 
pen 
B 
gi 
oO 
rl 
et. 
o 
+ 
oe 
*% 
E 
o 
. 
= 
tem ey, bym ing as Ae incombulti aie 
materials, as albeitos, or wire; but fti oil does not 
= evaporate, but ea a ‘cal perce of grofe fixed 
. 8 
of this fuel; but this is the. cael character 
naar ae ee ian conftantly sceummnate: clogs 
, that the oil cannot afc end, the 
di 
tile than others. 
and the only remedy is to change the wi 
we can hardly do this and be fure of keeping always an equal 
“The fecond kind of fuel mentioned, peat, 1s fo {pongy 
that, compared with the more folid fuels, it is unfit to 
employe heats. eo is — bulky 
: we t into a furnace, at a a qua 
tity eA a with the quick eonfumption that ‘oul 
eceffarily go on when the = is violent. ‘There no 
doubt, a great difference in this refpec&t among diferent kind 
coal. en prepared fo in that manner, it is capable 
£ being made to burn more flowly and gently, or will bear, 
witho aie extinguifhed altogether, a greater diminution 
arce 
is. prepared by piling up billets ‘wood in 
» fo ea through the 
odare put eae thofe below, and 
the whole i is fo conftruéted that, when kindled, it kindles 
— over the whole pile in a very fhort time. It would 
burft out into a blaze, and be quickly confumed to afhes 
were it an covered all over with earth, or clay, beaten clofe, 
leaying cpenings at all si fpiracles. e are ce apets 
watched; and, whenever the white watery {moke ad 
ferved to be fucceeded - int blue, an I pene seer fn okey 
the whole is immediately it d st iis being the indication 
and the burning of the 
rue coaly mmencing. Thes i is a pretty ftrong red 
heat raifiel ‘rough the whole mafs, and all the volatile mat- 
ters are diffipated hy it, and nothing now remains but the 
The holes being all ftopped i in fucceffion, as this 
change re the frnoke is obferved, the fire goes out for want 
of air. The pile is. now allowed to on This r neqiures 
of 
quantities may 
ing ood clofe veffels. 
a ade - any time, by ce oe wood in lead ise 
and re 
This j is ae chief fuel. ufed by the chemitts abroad, and 
has many good properties. It kindles quickly, emits ce 
watery or other vapours while burning, ad isos = ed 
leaves few afhesy and thofe ve caiied 
Le ooo o the current 
eep it burnin 
produce as se a heat as can he obtained by any ; but 
in thofe violent sare it is quickly confumed, and needs to 
be frequently fupplied 
offil coals. charred, called cinders, or boas have, ig 
many refpects, the. fame popes as charcoal of wood; as 
kindling more readily in furnaces than when hig are net 
charred, and not pane watery, or other * gro s {moke, 
while 
