1:^2 FUR 
FU'RLONG.yr [panlanj^, Sax.] A meaftireof lengtii, 
Containing 660 feet, or 220 yards, or 40 poles or perches, 
or the eight.h part of a mile.—If a man (land in the middle 
of a field and fpeak aloud, he fliall be heard a furlong in a 
..round, and that inarticulate founds. Bacon. 
FUR'LOUGIT, f. ^verlof, Dut.] A temporary dif- 
milTlon from military lervice; a licence given to a foldier 
to be abfent ; 
Brutus and Cato might difcharge their fouls, 
And give them furlo's for another world; 
But we, like fentries, are oblig’d to ftand 
Tn ffarlefs nights, and wait th’ appointed hour. Drydcn. 
F'UR'MENTY, yi [more properly frumenty, ox fru- 
met.v, of frummtum, Lat.] Food made by boiling wlieat 
in milk: 
Remember, wife, tlterefore, though I do it not, 
n lie (eed-cake, the pafties, and furmmty pot. Tujfer, 
F'UR'MION, a town of Venetian Iftria; eighteen 
miles eafl-foutli cafi; Unaago. 
FUR'NACE, f. \_jurnus, Lat.] An inclofed fireplace. 
— The filling pot is for filver, and the furnace for gold. 
Brov .—Whofo f.illeth not down and worfliippeth, fiiall 
the fame hour be call into tlie mid(t of a burning fiery 
jurnace. Dan. 
Heat not a furnace for your foe fo hot 
Th.at it may finge yourfelf. Shakefpeare, 
FtTRN.vCES have increafed in number and variety, in 
proportion as tliey liave daily become more and more in- 
Rninienta! in dilFufing the light of fciencc, in promoting 
the exteiifion of the arts, and in perfedling and enlarging 
our mod valuable manufaddures. The origin of the fur¬ 
nace might be traced to the mod remote antiquity ; but 
-its improved condriidlion, and application to fo many 
important objedfs, are to be attributed to the ingenuity of 
the modern chemids. Indeed, it was impoflible for them 
to fucceed in any of the effential operations by the agency 
of fire, without Rich aids; and accordingly we find feveral 
furnaces condrudled for thefe ufes, which foon became 
the foundation for others in the large way. Among thofe 
adapted to chemical experiments, are, i. The fmall 
evaporating furnace, for digedion, difiillation. See. 2. The 
reverberatory or condenfing furnace, for operations with 
the retort. 3. Macquer’s docimadic or allaying and 
cupelling furnace, for fmelting ores, and refining metals. 
4. Dr. Black’s regider furnace, for the more equable 
didribution of heat, or rather for more immediate and 
iiitenfe combudion. See thefe feveral furnaces deferibed, 
with figures of them, in the article Chemistry, vol. iv. 
p.191, 192. 
BLAST FURNACE. 
This is uftially condrmfted in a large conical or quad- 
rangalar building, and calculated on a principle of very 
high Combudion, for the purpofe of fmelting iron-done 
#f ores, in the great iron founderies. Its velocity is pro¬ 
moted by the impelling power of a biovving machine, 
forcing the whole contents of the air-pump tlirough one 
or two fmall apertures called nofe-pipes; and in pro¬ 
portion to the power of the engine, air of various denfities 
can be produced, fo that denfriy and velocity are inti¬ 
mately conneCIed, and mutually implied. The well, 
known combudibility of iron, and the indifpenfible ne- 
cellity of exciting combudion by the introduction of large 
quan.ities of condenfed air into this furnace, in contaCt 
with ore in various dates of maturity as to feparation, 
into contact with iron exiding in all the modifications of 
quality as to carbonation, and into contaCh with an im- 
menfe body of ignited fuel, render this procefs the mod 
important in the grand fcale of our manufactures. The 
annexed engraving, fig. i. reprefents a blad-furnace, 
with part of its blowing machine. A, the regulating 
cylinder, eight feet diameter and eight feet high. B, the 
FUR 
floating pidon, loaded with weights proportionate to the 
power of the machine. C, the valve, by which the air 
is paired from the pumping cylinder into the regulator : 
its length is twenty-fix inches, and breadth eleven inches. 
D, the aperture by which the blad is forced into the fur¬ 
nace. Diameter of this range of pipes eighteen inches. 
The wider thefe pipes can with convenienry be ufed, the 
lefs is the fiiClion, and the more powerful are the effeClS 
of the blad. E, the pumping cylinder, fix feet diameter, 
nine feet high : travel of the pidon in this cylinder, from 
five to feven feet per droke. F, the blowing pidon, with 
one of the valves, of which there are fometimes two, and 
fometimes four, didributed over tlie furface of tlie pidon. 
The area of eacli is proportioned to live number of valves : 
commonly they are ia-^i6 inches. G, a pile of-folid 
done building, on which the regulating cylinder reds, 
and to which thcflanch and tilts of the blowing cylinder 
are attached. H, the fafety-valve, or cock ; by the fimple 
turning of which the blad may be admitted to, or Ihut 
off from, the furnace, and palled off to a collateral tube on 
the oppofite fide. • I, the ttiyere, by which the blad 
enters the furnace. The end of the tapered pipe, which 
approaches the tuyere, receives fmall pipes of various 
diameters, from two to three inches, called nofe-pipes. 
Thefe are applied at pleafure, and as the drength and 
velocity of the blad may require. K, the bottom of the 
hearth, two feet fquare. L, the top of the heartli, tvio 
feet fix inches fquare. KL, the height of the hearth, fix 
feet fix inches. Lisalfo the bottom of the bodies, which 
liere terminate of the fame fize as the top of the hearth ; 
only the former are round, and the latter fquare. M, 
the top of tlie bodies, twelve feet diameter and eight 
feet of perpendicular height. N, the top of the furnace, 
at which the materials are charged ; commonly three feet 
diameter. MN, the internal cavity of tlie furnace from 
the top of the bodies upwards, thirty feet high. NK, 
total height of the internal parts of the furnace, forty- 
four feet and an half. OO, the lining. This is done in 
the niced manner with fire-bricks made on purpofe, 
thirteen inches long and three inches thick. PP, a va. 
cancy which vs left all round the ontfide of tlie firft 
lining, three inches broad, and which is beat full of coke, 
dud. This fpace is allowed for any expanfion which 
might take place in confequence of tlie fwelling of the 
materials by heat when defeending to the bottom of the 
furnace. QQ, the fecond lining, finiilar to the fird. 
R, a cad iron lintel, on which the bottom of the arch is 
fupported, RS, the rife of the arch. ST, height of 
the arch ; on the outfide fourteen feet, and eighteen feet 
wide. V V, the extremes of the hearth, ten feet fquare.- 
Tliis and the bodi-dones are always made from a coa'rfe 
gritted freedone, whofe fraflure prefents large rounded 
grains of quartz, connefted by means of a cement lefs 
pure. 
Fig. 2 reprefents the plan of the hearth, and a view of 
the manner in which the falfe bottom is condrudled. 
A A, the bottom dones of the hearth. B, dratum of 
bedding fand. CC, padages by which the vapour, which 
may be generated from tlie damps, are palfed off. DD, 
pillars of brick. The letters in the horizontal feflion, 
correfpoiid to fimilar letters in the dotted elevation. 
Fig. 3, AA, horizontal feftion of the diameter of the 
bodies, tlie lining and vacancy for duffing at M, in fig. i. 
C, view of the top of the hearth at L, in fig. i. 
Fig. 4, vertical fide-fedlion of the hearth and bodies; 
(hewing the tymp and dani-dones, and the tymp and dam- 
plates. a, the tymp.done, b, tlie tymp-plate, which is 
wedged firmly to the done, to keep it firm in cafe of 
fplitting by the great heat, c, dam-done, which oc- 
copies the whole breadth of the bottom of the hearth, 
excepting about fix inches, which, when the furnace is 
at work, is filled every cad with drong fand. This done 
is furmounted by an iron plate o^cbnfiderable thicknefs, 
and of a peculiar lhape, d, and from this called the dam- 
plate. The top of the dam-done and plate is two, three, 
or 
