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S72 F I L 
and afterwards his life, by one of them. Lucretius is 
f iid to have ended his life by the fame way ; and Cains 
Caligula, as Suetonius reports, was driven into a fit of 
infanity by a filter given him by his wife Caefonia. Ovid 
alfo a flu res us that this was generally the effeCt of thefe 
artificial love potions. 
FILTH, f. [pilft, Sax.] Dirt; nafiinefs; anything 
that foils or fours: 
Wifdom and goodnefs to the vile feem vile ; 
Filths favour but themfelves. Shakefpeare. 
Corruption; groflhefs ; pollution.—Such do likewife ex¬ 
ceedingly difpofe us to piety and religion, by purifying 
our fouls from the drofs and Jilt/i of fenfual delights. 
TillotJ'on. 
FIL'TIIILY, adv. Naftily; foully; grofsly,—It (luck 
filthily in the camel’s ftomach, that bulls, bears, and the 
like, Ihould be armed, and that a creature of his fize 
fliould be left defencelefs. VEJlrange. 
FIL'THINESS, J'. Nafiinefs; foulnefs; dlrtinefs.— 
Men of virtue fupprefled it, left their fhining fhould dif- 
cover the others Jilthinefs. Sidney. —Corruption; pollution: 
They held this land, and with their Jilthinefs 
Polluted this fame gentle foil long time. Spenfcr. 
FIL'THY, adj. Nafty; foul; dirty: 
Fair is foul, and foul is fair, 
Hover through the fog and filthy air. Shakefpeare. 
Grofs; polluted. — As all (lories are not proper fubjefts 
for an epic poem or a tragedy, fo neither are they for a 
noble picture; tire fubjeCts both of the one and of the 
other, ought to have nothing of immoral, low, or filthy , 
in them. Dryden. 
FILT'J A, a town of Sweden, in the province of Suder- 
mania : ten miles fouth-weft of Stockholm. 
To FIL'TRATE, v. a. To drain ; to percolate; to fil¬ 
ter.—The extract obtained by the former operation, burnt 
to allies, and thofe afhes boiled in water and filtrated , yield 
a fiery fait. Arbuthnot. 
FILTRA'TION, fi. A method by which liquors are 
procured fine and clear. The filtration mod commonly 
in ufe is [training a liquor through paper, which, by the 
fmallnefs of its pores, admits only the finer parts through, 
and keeps the reft behind. Amongft the great variety of 
modern improvements in the arts, are feveral ufeful inven¬ 
tions for the purification of water, oil, and other fluids, 
by filtration. In fea voyages fuch conveniencies are often 
highly valuable; and even for domeftic ufes on land they 
are of great utility, particularly where no water can be 
had but from ftagnant pools, or fprings flowing through 
clay. The mod; Ample contrivance is the filtering ftones; 
next to which we might rank the filtering bafons of Mrs. 
Hempel of Chelfea, for which (he obtained letters patent 
in 1790. The idea of this invention might have been 
borrowed from the accounts given of the Egyptian al- 
karras or balajfes, jars for purifying the waters of the Nile, 
deferibed under the article Egypt, vol.vi. p. 385.—To 
compound the raw materials for thefe filtering bafons, the 
following directions are fet forth in the patent, viz. four 
equal parts, out of nine equal parts, of tobacco-pipe clay ; 
and five equal parts, out of nine equal parts, of coarfe fea, 
river, drift, or pit, fand ; thefe two materials, in the 
above proportion, are fufficient for the purpofe of making 
bafons to contain a quantity not exceeding one gallon of 
water, or other liquid. But the compofition, when con¬ 
fined 10 thefe vwo materials, often flies or cracks in the 
fi. . if larger bafons are attempted to be made with it. 
Mrs. Hempel therefore, in the fecond indance, compofes 
her filtering bafons of equal parts of tobacxo f/ipe clay 
and coarfe (ea, river, drift, or pit, fund; in the third in- 
fianee, : of three equal parts, out of nine equal parts, of 
tobac< o-pipe clay ; one equal part, out of nine equal parts, 
of Stourbridge clay, or clay from the furface of coal¬ 
mines, or any other clay of the fame quality ; one equal 
part, out of nine equal parts, of Windfor or other loam; 
and four equal parts, out of nine equal parts, of coarfe 
river, fea, drift, or pit, fand. Or, in the fourth indance, 
of four equal parts, out of eight equal parts, of tobacco- ~ 
pipe clay ; three equal parts, out of eight equal parts, of 
coarfe fea, river, drift, or pit, fand; and one equal part, out 
of eight equal parts, of that burnt ground clay of which 
crucibles are made. The bafons or other vefiels made of 
the materials mentioned in the fecoqd, third, and fourth, 
indances, will dand the heat of the fire much better than 
thofe made of the materials directed in the firft inftance ; 
and, therefore, the materials in the fecond, third, and 
fourth, indances, are bed calculated for manufacturing 
thefe filtering bafons, particularly of a large kind. The 
materials mud be worked together, moulded, and formed, 
as pottery is ufually moulded and formed ; and when the 
veffels are of that degree of drynefs which is ufual in the 
formation of pottery, the whole outfide and infide furfaces 
are to be (haved or turned off on a potter’s wheel, ready 
for burning; and, when perfectly dry, are to be baked 
in a potter’s kiln, as other pottery is ufually burnt or 
baked ; when they will be ready for ufe. 
A patent has alfo been granted to Mr. James Peacock, 
of Finfbury-fquare, London, for a filtering machine, dated 
December 23, 1791. This invention accomplifhes the 
purpofe of filtration, by caufing the turbid fluid to afeend 
through a medium of fine gravel, of progreflive degrees 
of finenefs, by which means the fouled water or other 
fluid becomes perfectly free from all impurities, without 
any noxious mineral quality, which the common filtering 
ftones are fufpedled-to communicate. Should, from con¬ 
tinual ufe, its operation become in any degree impeded, 
it may be cleanfed with the greateft facility in the fhort 
fpacc of one minute. A fpecimen of this machine is de- 
pofited for infpettion at the Guildhall in London. 
The editor of the Domeftic Encyclopaedia, recommends 
a very Ample apparatus, by which the pureft water may 
be eafily obtained. This contrivance is calculated on the 
plan of the celebrated filtering machine ereCted at Paris, 
in the vicinity of-the Samaritaine, and by means of which 
the foul water of the Seine is fo completely purified, a& 
to be diverted of its laxative properties. Profeftor Parrot, 
iun. of Paris, has alfo invented a very ingenious and port¬ 
able filtering machine, the form of which is reprefented 
in the annexed figure. The principal part of the machine 
confifts of a fquare velfel, 
bent in the form of an in¬ 
verted fyphon. The curve 
may be circular, elliptic, or 
in any other direction. This 
veftel is filled with fine fand, 
till nearly the height of the 
dotted line x,y, which de¬ 
notes the afeent of the wa¬ 
ter to D, whence it flows in¬ 
to the receiver. The part 
marked A, B, fliould always 
projeft above this line, ac¬ 
cording to the fize of the 
filtering machine. To A, 
B, there is attached a wool¬ 
len bag, which is open at 
the top, and the lower part of which touches the fand. 
It ferves the purpofe of collecting the coarfeft impurities, 
and thus preferves the fand for a longer time from be¬ 
coming foul. The bag, therefore, may occafionally be 
removed, and rinfed in clean water. It is evident, that 
the water flows at A, through the bag into the filtre, and 
rifes at the place marked D, which is confiderably lower 
than the former. It affords a pleafing fight to obferve the 
mod limpid fluid penetrating the uppermoft ftratum of 
fand, perfectly fimilar to that oozing from the pureft na¬ 
tural fpring.—This machine, made of block-tin, confided 
of the following dimenfions: the fmall diameter B, E, 
was eight Paris inches; the length of the whole machine, 
eleven inches; confequently the thicknefs of the velfel 
A, B, 
