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alkali d a p~rticular kind, whi,h is its natur,1b~fis j ~nd
confequently it is in the form of a neulral fah . T his
fah is pleOlifullyelilfolved in Ihe walers of the oce.n,
and whell oblained Ihcrefrombears Ihe name of fon f dt.
lt is alfo found in Ihe eanh in v.1l cryllalline man~s. and
i, Ihen called¡'/'g,m; fo that fea·fall and fal .gemare
bUI one and Ihe I~me fort of fa lt. diffaing very liHle
frumeach olher, exccpt 3S to the places where Ihey are
found.
[n the earth are alfo found fpring, anel fountains,
",hofe waters are flrong brines, a grw dcal of fea·f:dl
being ditrolved in them. Thefe fprings cilher rife di·
reélly from Ihe fca, or run Ihrough fome mines of fal·
gem, of which they lakc up a qoanlily in Iheir palrage .
As Ihe or at IeaJl nearly Ihe fame quanlily of
fe¿·f.11 will conlinue dilrolved in cold waler as boiling
water willlake up, It caonot IbOOI, as nitre does, by Ihe
mere cooling of the waler in which il is dillblved: il
cryfl.Jlifes onlyby Ihe means of evaporation, which con·
tinually letrcns Ihe proponion of Ihe wmr to Ihc fall ;
fo Ihal it is allVay' eap.ble of conlaining jull fo much the
lefs fea·fall the more there is cryllallifed.
The brine Ibould nOI boil afler you perceil'e the pel.
liele of lillle cryltals be~inning 10 fOI In en its furface j
for Ihe calmnefs of the Irq uor aJlows Ihem10 form more
regul.r1y, and become larger. Nor afler Ihis fllould Ihe
evaporation be hurried on too fall j for a faline cruf!
would form on the liquor, whiclr, byprevenling the va·
pours from béing cal ried olf, would obllruél Ihe cryllal.
tifalion.
If the ev.poration be conlinued aflH the liquor ceafes
10 yield any cryllals of fed , h, other will be
obtainc~ of an oblong four·fided form, which have a bir·
ler lalte, and are almofl moin. This fon of falt
is known by Ihe name of E/10m¡o/t, whiéh il olVes 10 a
fal l fpring In EnglanJ, frcm Ihe water of which il l was
fi rll eXtldaed. This (,dl, or ralher faEne compound, is
" congeries of Glauber', fall and fea·fall, in a manner
confounded togelher, and mixed wilh fome of the mo·
I h~r of fe. ·fall, in which is conlained .a kind of bitu·
minous nutler. Thefe I\VO n~\IIral {ahs, whieh conlt;·
tu~e lhe Epiomf. II, may be eafily feparated {rom each
",her, by means of crylt.f1ifalion only. Epfom {all is
purgalive .nd biner j and Ih\!refore named ¡al colh/lrti
CIII/I OIMrUll/, or binér purging fa!ts.
TI.<re are difforenl melhuds ufed in great works for
oblaining fca·fall ou~ of waler in IVhich il is dilfolved.
The fimpleU and eafiell is thal prJétifed in France, and
in .:1Ihofe counlric, whlch are nOI colder. On Ihe fea·
Ilwe Ihey lay OUI a fort of broad fl"Jlow pils. pans, or
ralher pOllds, which Ihe fea fllls wilh Ihe lide of flood.
\\lhen the ponds are thus fiJlcd. they Ilop Iheir commu·
niealion \Vilh Ihe fea, and leave !he water to evapOrate
by Ihe heat of Ihe fun ; by whlch means aJl Ihe f.11 con·
tained in it necetrarily cryllaJlifes. Thefe pils are called
Jo/t pondJ. Salt Can bemade in Ihi, way inIhe fummer·
time only, al leall in F"nce, and olher counlries of the
f. me Icmper. lure j for during the wioter, when Ihe fun
has Ids power, and rains are frequenl, this method is
001 pr./\ic.~le.
For Ibis re.foo, as it ofleo raios in Ihe provinee of
s T R Y. 12 3
Normandy, lhe inhabitants lake anolher way to eXlraa
from fea·water. The labou«rs employed for Ihis
purpole raife heaps of fand on Ihe fllOre, fo Ihat the tide
wmers and drenches them when il flow" and leaves the
fand dry when il ebbs. During the ioterval between
two lides (lf flood the lun antl the .ir eafily carry off the
mnillure Ihal was lefl, and fo ' Ihe fand remains impreg.
naled wilh . 11 Ihe falt Ihat was contained in Ihe evapo.
rated waler, Th"s Ihey lel il acquire al much fah as it
can by feveral relurns of flood, and Ihen walb it OUI wilh
frcfh waler, which I)¡ey evaporate over a firc in leaden
boilers.
To ohlain Ihe fah from brine.fprings, the water oeed
only be ev. porated: bUI as fever.1of Ihefe fprings con·
rain 100 lillle fah 10 pay Ihe charges Ihal would be in–
curred, if Ihe evapor.tion were effeéled by the force of
fire only, Ihe manufa/\urers have fallen upon a lefs ex·
penlive method of geuing rid of Ihe greatefl parl of the
waler. and preparinJ tire brine for cryHdllif.tion, in mueh
lefs lime, and wilh much lefs fire, Ihan would olherwife
have been necetrary.
The method confill, in making Ihe water fall from ~
cenain height on a greal many fmall fpars of wood,
which divide it into partieles Iike rain. This is perform–
ed under Ibeds open ro aJl Ihe winds, which pafs freely
through Ihis anificial lbvwer. By Ihis mean! Ihe waler
prefcOls 10 Ihe air a greal eXlent of furface, being in·
deed reduceq almofl eotirely to , and Ihe
ration is carried on wilh greal eafe and expedilion. T he
waler is raifed by pumps 10 Ihe height from whieh it is
inlended to fall.
ExptrilllWIJ ce¡mrning Ih. dmm,?fition ej Stafall,
b¡ IIllanl oj th, phlegij/,n. Kunckel'J PhoJphoruJ.
" Or pure urioe that has fermenled five or fix day'
take a quanlily in proponion tO the quantilYof phofpho.
rus you intend 10 m~ke: it requires about one Ihird part
of a hoglbead 10 make adram of phofphoru!. Evaporate
il in iron pans, lill it become eloncd, hard , black, and
nearly like chimney·foot; at which time it wiJl be re~
duced 10 auout ¿ fixtÍelh par! of ils original wcight be·
fore el'aporation.
" Wheo the urine is 6roughl to Ibis condilion, pUl it
in feveral ponions iOlo fo many iron pOIS, uader which
you mul! keep a pretty brilk fi re fo as ro make their bot–
loms red, and Ilir it incelfantly lilJ the volaule Call and
Ihe fetid oil be almoll \VhoJly dlflipaled, lill Ihe matler
ceafe ro emil ally fllloke, and till it rmelJ like peach–
blonom,. Then pUl OUI Ihe fire, and pour on Ihe mal'
ter, which wiJl no\V be rednced to a powder, fomcwhat
more Ih~n Iwice its weight of warmwaler. Slir il about
in this w.ler, and leave it to fo ,k therein for l\Venly.
/ollr houes. Pour off Ibe \Valer by indina'ion j dry Ihe
dlcnched mauer, and pulverife il. The previous cal·
cinalion earries off from the tnauer aboul a Ihird of il;
weighl, and the lixivialionwalbes out half Ihe remainder.
" Wilh .,hal remains thus caJcined, walbed, and
dried, mix half ils weighl of grave!, or yelJow free·
none rafped, having fifted out and thrr,wn away alJ the
finen partieles. River·fand is not prop" on this occa·
Gon, becaufe it Bies in a hot 6re. Thea add to Ihis
mixture