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t-S cr^O:«Wo ^ 

Robert E. Gross 

A Memorial to the Founder 
of the 

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f M • r 1 • f. 

• *^ " •^ R A L 


PROPOSKD in tliat A R T, 
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IT is an old remark, that ail arts 
a;ul fcicices have a timinal de- 
pendance upon each other. The phi- 
lofophcT borrows many experiments 
from the mechanic, which affifl: him 
in his fcarchcs into nature ; the me- 
chanic avails himfclfof the difcove- 
ries of the philofophcr, and appHes 
them to the iifcs of mankind. Thus 
men, very different in genius and 
purfuits, become mutually fublcrvi- 

a 3 ent 


ent to each other ; and a very ufe- 
ful kind of commerce is eftabHfhedj 
by which the old arts are improved, 
and new ones daily invented, and 
the knowledge of nature is continu- 
ally advanced, and brought nearer 
to perfection. Thofe trades there- 
fore and occupations of life, which 
formerly brought honour to their in- 
ventors, ought not now to be treated 
with contempt, becaufe grown vul- 
crarand common : but rather, for their 
general ufefulnefs^ fhould be held in 
the greater cfteem ; and in a parti- 
cular manner they demand the re- 
gard of philofophers, who have been 
taught by the noble Verulam, that 
the * hijlory of mechanic arts is a ne- 
ce(fary part of that knowledge^ upon 

* Verukm Be augment, fcicnt. Lib. ii. c. 2. 



ivhtch alone ^ as oh a firm hafis^ can he 
bmlt that true fae nee of nature^ vjhich 
is not taken tip in vain and fruitlefs 
f peculations^ hat eff'eihially labours to 
relieve the necejjittes of human life. 

Amongst thcfc vulgar arts, that 
of making fait, or of preparing and 
fitting it for the ufes of mankind^ hath 
been thought worthy the notice of 
many great and learned men, as well 
amongft the antient as moderns. Thus, 
many things relating to this art are 
recorded by Cato^ and Pliny the Na- 
turalift. And, if we fearch the wri- 
tings of the moderns, we fhall find 
the improvements in this art care- 
fully colleded by George Agriccla, 
Frederick Hoffman^ and many other 
excellent phyjiaans ; to which body 

a 4 of 

viii PREFACE, 
of men wc arc chiefly indebted for 
thofe memoirs, that liave been tranf- 
mitted to us, relating to its hifl:ory. 
Had thofe great men been as diligent 
in improving this art, as they were 
in recording the improvements made 
in it by others, there would not now 
have been occafion to remark, that, 
after the pradlicc of fo many ages, an 
art fo fimplc-i and withal fo nectjfai'y^ 
hath not yt been brought to any grea& 
degree of perfeBion, 

That this art was capable of great 
improvements, efpecially as pradifed 
in Britain, was the fentiment of the 
/JcW.V'oa-f/yfoon after its inftitution; 
at which time that renowned body 
was very intent upon bringing it to 
greater perfedion ; as may be gather- 


ed from the inquiries and fuggeftions 

of Dr. Beal, and the hiftories of fe- 

veral methods of making fait, which 

then were pubHiLed by that Society, 

And although the Engliflihave, fince 

that time, confiderably improved 

their methods of boih'na fait; yet 

this di t IS fl'ill praH'ifed w'lth greater 

Jkill mid fticcefs by their allies the 

Dutch ; as the fupcrior goodncfs of 

the hill, cured with their fait, doth 

fufficiently prove. 

That auguflbody the Commons of 
Great Britain^ having therefore taken 
into confideration the great impor- 
tance of this art, judged fome im- 
provements propofcd therein worthy 
ofits regard and encouragement; well 
knowing, that could this he brought to 




the fame perfecfton m Bi itatri^ as 'ai 

fome netjijohonring county tes^ large fums 
of money might he favedm the nation^ 
which are noiv annually paid to the 
French and other foreigners \ its fifhe- 
ries might be greatly improved \ and 
its navies and commerce^ and many 
of its richejl colonies would no longer 
depend upon its enemies for one ofthofe 
necejfaries^ without which they cannot 

These confidcrations have in- 
duced me to give a brief account of 
the various methods of making fait 
which now are ufed in Great Bri- 
tain, and in other countries where 
this art is pradlifed with more fuc- 
cefs ; and alfo to attempt feveral fur- 
ther improvements in this art for the 



ufeof theBritifli dominions. How far 
I have fucceeded in thcfe attempts will 
beft appear^ if the public fliall think 
the following propofals fo far worthy 
of their attention as to merit a fair and 
impartial trial. The principal conclu- 
lions, deduced from a variety of ob- 
ferv^ations and experiments, are as fol- 
lows. Firfl-, That by the methods here 
pyopofedj an excellent bay /alt may be 
madetn Britain^ tn very large quanti- 
ties^ fo as to be afforded cheaper than 
at the prices paid for foreign fait y and 
that the Britiffj colonies in America 
may very commodioufly be fupplied 
with bay fait of their own manftfa^ure^ 
without having' re cotirfe for it to the 
French y Spam ar-ds^ and Portugueze, 
Secondly, That^ by the methods here 
propofed^ ci excellent kind of refined 



white fait may he made tn Britain^ as 
well from fea water ^ and rock falt^ 
as from natural hrine^ m any quanti- 
ty wanted^ fo as to be afforded cheaper 
than foreign bay fait ; and which wiU 
alfo he better than common bay fait 
for curing fifio^ fie flj^ and other provi- 

In forming thefc conclufions, I have 
had ail impartial regard to truth, 
and to the utiHty of the public, with- 
out attending to the private advan- 
tages of any particular fet of men. 
Some things perhaps may here be of- 
fered which have efcaped the notice 
of others. The fenfe of this, together 
with a defireof promoting the pubUc 
advantage, have induced me to com- 
municate the following; flieets. And I 


PREFACE. xiii 

rather chofe, at this time, to fubaiic 
them to the candour of the reader, 
defective as they arc, than by defer- 
ring the publication with a view of 
making them more accurate, to let 
flip the prcfent occafion ; which in- 
deed feemcd the moft favourable for 
attempts of this kind, as the nation is 
at pre fen t engaged in war with feve- 
ral potent enemies, from whom it 
hath heretolore been chiefly fupplied 
with this commodity. And more ef- 
pecially as by the late acquifltion of 
Cape Bretoyj^ an opportunity is offered 
of extending the BntiJJj Jijljenes^ to- 
wards which there feems a laudable 
zeal in the nation ,• wherein an opi- 
nion hath alfo prevailed, that ihecjla- 
bUflmig of fijhcr'ies in the North of 
Scotland would be the beft means of 



aflFording an ufeful employment to the 
more uncivilized inhabitants of that 
part of the kingdom ; for carrying 
on of which they are moft commodi- 
ouily fituatcd. 

What Mr. Lowndes hath lately 
done towards the improvement of 
brine fait, may, perliaps, by fome, be 
thought to fuperfcde the neccfTity of 
any further a ttemptsy^;'/,^^/<?zv;/(7 and 

txtemlnig our fait manufacture, 1 am 
very far from defiring to depreciate 
tlie endeavours ot that gentleman, 
which have met with parliamentary 
encourao-ement : and had his difcove- 
ries appeared to me fufficiently com- 
plete and extcnfive, Ifhould not have 
given the public and myfelf this trou- 
ble. I make no doubt but that the 



ipecimen of fait, which he exhi- 
bited before the College of Phyfi^ 
cians, was a ftrong and fure falt^ 
fince fuch it appeared to that moft 
learned body. Whether the alhtm 
Wixed wuh tt (agreeable to the anci- 
ent pradiccof the Chcfliire fait boil- 
ers) contributed any thing to its good- 
nefs, will be more properly confidered 
in another place. It is only nccef- 
iary here to obfervc, m jfijUficat'ion of 
the prefeut in:dertakmg^ that Mr. 
Lowndes's method of makinor fait 
for curing provifions, doth not ap- 
pear to be the hejl that may be put in l; 

pradice ; fince I hope to /liew, that 
by other methods a pnyer a,ul Jh onger > 

Jalt may he marle^ and at a kjl ex pence, 1 

Neither is his method fo genet al and 
extenjlve as fcems to be rerjuired 


xvi P R E F A C E. 

for the public good ; fincc Mr. 
Lowndes confines it almofl: entirely 
to boiled brine fait ; and liath given 
no direcSlions concerning the pre- 
paration of bay flit. lie indeed 
propofes to nielioratc the Biitilli 
fca fait, but fecms to dclpair ot 
i^reparing a fait either Irom fca wa- 
ter, or the Englilh rock- fait, fit for 
the ufes of the navy or fiflieries ; 
although the Dutcli fait, which is 
the Hrongeft: and pureft boiled fait 
now made, is entirely a marine 
{lilt, and even the brine, ot which 
Mr. Lowndes makes his fait, is only 
a folution of the Englifii rock- 
falt, often in very impure water, 
as is well known to naturaliils. 

I iN T R O 

( xvii ) 




F fdlt in general ; ivherein are contained 
frjcral particulars relating to the Na- 
tural Hiltory of common bait, and its va^ 
rious kinds are diftinguifi:ed^ according to 
their origin and manner oj preparation, p. i. 


The Art of preparing Bay Salt. 


Of bay fait in general. 12 


Of has fait extra^ed hy a total exhalation of 
the icater ivherein it zvas dijjohed. 1 3 


Of bay Ja It drawn from the brine of ponds and 

lakes, and firjl of fait thus prepared, in the 

Cape de Verd ijlands, ^ ^ 

b SECT. 



Of bay fait tnade at Tortugas and other places 
in America. page 24 


Qf marine bay jalt prepared in France and 
other parts of Europe, ' 3 1 


The Art of prc{>aring White Salt. 


Of li'hitefilt m gemral. 4 5 


Of fait boiled from fea ivater, 49 


MifcelLineous obferiaticns and cautions relating 
to the foregoing procefs. 63 


Memoirs for an Analyfis of fea ivater, y^ 


The method of boiling brine fait, 93 




Of the additions ^ or feafonings ufed by falt^ 
boilers. page 109 


OJ white fait prepared from fea water, and 
other fait waters , firji heightened into a 
flrong brine by the fun. 120 


Of white fait made from ajirong brine drawn 

from earths^ finds^ and f ones impregnated 

with fait. I •7'^ 


^f reffied rockjalt. 1 3 3 


Of the Dutch method cj preparing fait upon 
flit, 140 


Of the qualities of the feveral kinds of bay 
fait. i^y 

b2 CHAP. 



Of the different qualities of ivbitefalt, p. 152 


Of the ufes of fait as a feafoning to our food. 


Of the ufe of fait as a condiment or pickle, 1 6 1 


In ivbicb, frccral methods arc propofcd for 
making bay fait in England ^ a?id other parts 
of the BritiJJj dominions. 171 

L E M M A I. 

^he quantity of water which annually falls in 
rain, fnou\ and hail, is very different in 
differejjt parts oj Great Britain ; there 
commonly falling alrno/t double the quafitity 
on thewejtern coajls^ that falls on the eajlem 
coajls of that ifland, lyz 


^he quantity of rain which Jails in Lanca- 
cafiirCy during the four hottef months oj 



the year, "jiz. May, June, July, and Au- 
gufi, doth not, at a medium, amount to more 
than a third part of the quantity of water ^ 
which falls in rain, fnows^ and hail, dur- 
ing the ivhole year. page 1 76 


^he ivater, which ajcends in vapours fro fn the 
fea, very greatly exceeds that which defends 
thereon in rain and other aqueous fneteors : 
But the quantity of water, which ufually 
exhales from a given part of the ocean in 
a given time, cannot, with any cxaSinefs, be 
determined, 1 77 


72)^ quantity of water which commonly eX' 
hates in Great Britain from fiallow ponds 
during the Jour hottcji months of the year^ 
greatly exceeds the quantity of rain which 
commonly falls on the furface of thofe ponds 
during the f aid months. 18^ 

P R O P. I. 

In fe^oeral parts of England large quantities 
of bay fait may be extradfed from fea wa- 
ter during the hottejl months of the year ; 
by receiving the folt water into ponds, and 
fuffering its aqueous parts thence to exhale 



by the heat of the fun^ and the operation of 
the air a?id winds. page 189 


Jn feveral parts oj England large quantities 
oj bay fait may irry commodioufly be ex- 
tradlcd from Jca ivatir^ ^/^^r the fame man- 
ner that is praclfed in France ^ and in other 
parts of Europe. 193 


Bay fait may be extracted in England from 
J'ea ivatcr in larger quantities^ and with 
more certainty than by the foregoi?ig metLx)d^ 
if care be taken to prejer've the brine con- 
tained in the J alt pits from being diluted 
with rains, and to promote the evaporation 
f)f the water by feveral artificial ?neans^ 
which may eafily be put in pra5lice. 201 


Jn feveral parts of England large quantities of 

excellent bay fait may, with great cafe, be 

prepared from the natural brine of fait 

fprings, and alfo from rock fait diffolvcd in 

weak brine, or fea water. 206 


Bay fait may be prepared in England by the 
foregoing methods at a very moderate ex- 

I pencey 

CONTENTS. xxlli 

pence, equal in goodncfi to the bcfi foreign 
bay J'alt^ and in quantity fujicumt Jor the 
confumption of all the Britifi domimom. 

page 2IO 


In federal of the Britijh coIo?iies in America, 
bay fait might, ivith little expence and trou- 
ble^ be prepared from fea 'water ^ in quanti- 
ties fujjcient to jupply the Amcricayififieries^ 
<ind all the other occafiom of thofe colonies^ 
Jo as to become a confiderable branch of their 
trade. 2 1 6 


In mhichfome metlxids are propo/ed for prepa- 
ring lihite Jalt ft for prejerving provifions. 


L E M M A I. 

In the common proccffes for making ivhitefaltj 
the fait is deprived of a confiderable part of 
its acidfpirit by the violent boiung ufed in 
its preparation, 221 


Mofl kinds oj white fait are rendered impure 
by the mixture of various heterogeneous fub- 
fiances. 23 r 

L E M- 

XXIV C O N T E N 1' S. 


White Jalt^ h\ the i)!o!int cociion commonly 

ufed in its preparation^ is rendered lefs Jit 

for prefervitig Jlc^^ fjh^ and other provi- 

JionSy than it would be ij prepared ivith a 

more gentle heat. page 239 


The heterogeneous fuh/iances which are com- 
monly mixed ivith ivhite falt^ render it lefs 
proper for preferring provifions^ than it 
would be if Jeparated from them. 247 

P R P. I. 

Trom fea water ^ foffi^ fi^^^ ^^ natural brine ^ 
to prepare a kind of white fait proper for 
curing fill\ fep.\ and other provifons. 253 


In feveral parts oj Great Britain^ white fait 
might be refined by the Joregoing ?nethody 
at a fmall expeuce^ and in any quantity 
wanted. 268 

1 N T R O- 

( ■ ) 


Of Sa LT in general, 

TH E fait, which we ufe as a feafon- 
ing to our food, is, of all falts, the 
mofl: excellent', and alfo the mofl 
common. It hath pleafed the author of 
nature to provide mankind with ample l1:ores 
of this mofl: ufcful and necelTary commodity. 
There are few countries which do not 
afford vart: quantities of rock or foffil fait. 
* Mines of it have long been difcovered and 
wrought in England, Spain, Italy, Germany, 
Hungary, Poland, and other countries of Eu- 
rope. In feveral parts of the world, there 

' The fuperior excellency of common falc, appears 
from ks extraordinary ufes to mankind in rheir food, ks 
admirable efFc(fls upon meraLsjand many other properties. 

* Amongft the fait mines of chief note are ihofe of 
Northwich in Chcfhirc, Akomonte in Calabria, Hall in 
Tyrol, Cardona in Catalonia : alfo thole ftupendous mines 
at Wilizka in Poland, and Soowir in Upper Hungary ^ 
of which fee zccoums in Phil. Tranf. N** 6l and 413. 

B 3r« 


are huge mountains which wholly confill: of 
foflil fait. 3 Of this kind are two mountains 
in Ruffia nigh Aikacan j feveral in the king- 
doms of Tunis and Algiers in Africa j and 
feveral alfo in Afiaj and the whole ifland of 
Ormus in the Perfian gulph almofl: entirely 
confills of foflil fait +. The new world alfo 
is flored wi'h treafures of this ufeful mine- 

' The re/' ciul and learned Dr. Shaw gives us the 
following account of the fait of omc inounrains in 
Algiers. " Jibbcl Had-dcffii is an entire mountain of 
" fait, firuated near the eaftcrn extremity of the lake 
*' of Marks. The fait of it is of a quite different quality 
*' and appearance from that of the falinae, being as hard 
" and folid as ftonc, and of a reddifli or purple colour. 
" Yet what is wallicd down from thcfe precipices by 
" the dew?, attaineth another colour, becoming as white 
" as fnow, and lofing that fhare of birternefs which 
" is in the parent rock fait. The fait of the mounrains 
" near Lworaiah and Jibbel Minifs is of a grey or 
*' blueifli colour, and, without fubmitting to the like 
" accidental purification as at Had-dcfla, is very agree- 
" able to the palate^ the fiifb efpccially, being fold ac 
" Algiers for a penny the ounce." See his Travels^ 
p. 229. 

■♦ " Sunt et montes nativi falis, ut in Indis Oromenus, 
" in qua lapicidinarum modo caedi:urj renafccns : ma- 
** jufque rcgum veftigal ex co eft. quam ex auro atque 
** margaritis. EfFoditur ec e terra, ut palam eft, hu- 
" more denfato, in Cappadocia. Ibi quidem casditur 
*' fpecularium lapidum modo. Pondus m.tgnum glebis» 
** quas micas vulgus appellat. Carrhis Arabiie oppido 
** muros domofque maftis falis faciunt, aqua ferruminan- 

tes.'' Ita Plinius Nat* Hj/f, lib. x.\-Ki. c. 7. 



ral, as well as with all other kinds of fubter- 
ranean produftions 5. 

Moreover, the fea affords fuch vafl 
plenty of common fait, that all mankind 
might thence be fupplied with quantities 
fufficient for their occafions. 

There are alfo innumerable fprings, 
ponds, lakes, and rivers, impregnated with 
common fait, from which the inhabitants of 
many countries are plentifully fupplied there- 
with. % 

In fome countries, which are remote from 
the fea, and have little commerce, and 
which are not blefled with mines of fait, or 
fait waters 3 the ncceflities of the inhabitants 

* '' In thefe parts [of Peru] is alfo found greac 
" abundance of the mine or rock fair, which is mafly 
" and tranfpnrenr, looking like the pureft cryftal. Jul- 
*' loma ^ath in it plentiful veins of this kind of lalt. 
*' Many years ago the inhabitants of Curagnara de Ca- 
" rangas have enriched themfelves by digging of rock 
" fair ; and of late years they have difcovered veins of 
" it near the river of Langacollo. But the (alt mines 
" of Yocalla, which God hath created near unro the 
" rich mountain and ci y of l^otoli, that nothing mighc 
" be wanting that was neceflary for the working of its 
" ore, yield fuch abundance of fait as is incredible j 
" whereof is daily fpent in the working of metals at the 
" lead fifteen hundred quintals, and this confumption 
" hath lafted for many years." Alonfg Barba, Trgatife 
efmetaJs, ml/itSy ^V. Chap. vii. 


have forced them to invent a method of ex- 
trading their common fait from the allies of 

^ The murianc fair of vegetables was dcfcribcd by 
Dr. Grew under the title of lixiviated m irine falc. Lccw- 
cnhoeck obtained cubical cryftals of chis fait from a 
lixivium of foda or kelp, and alfo from a foUuion of 
the lixivijl Ll: of Carduus bencdidtus ; of vchich he harh 
given figures in a letter to the Royal Society, publifbcd 
in N^. 173 of ihc'ix TranfrMiins. Dr. Dagner, in Ait. 
Acad. N. C. vol. V. obf. 150. rakes notice of great 
quantities of it which he found mixed in pot-aflics. And 
the ingenious Dr. Fothergill exrraifled plenty of it <ron> 
the afhes of fern. Sec Aledical EJfuys^ vol. v. arti- 
cle xiii. 

The muriaric fait which the excellent Mr. Boyle cx- 
tracflcd from fan-^.ivcr, and fuppofed to be produced from 
the materials ufcd in making glafs, was doubtlcfs fcpa- 
ratcd from the kelp made ule of in that procefs. See 
his ll'orks abbr. by Dr. Shaw^ vol. iii. p. 376. Kunkcl 
alfo informs u^, Obf. Chem. pc/i. p. 136. that he took 
an alcaline fait, and after calcining it with a moderate 
fire, dilfolved it in pure water, and pl.^cing the lolution 
in a cocl cellar, obtained fron\ it many cryftals of a 
neutral fait. He fuppofes that tlie alcaline fait was by 
the proccfs converted into this neutral lalt. But 'tis 
more rcafonable to believe, that the alcaline fait which 
he applied was not pure, but mixed with the muriatic 
fait of vegetables, which by this prOcefs was only fepa- 
rated from it. 

'Tis doubtlcfs chiefly this muriatic fait, which, in Tome 
of the inland parts of Afia, they extract from the afhes 
of duck- weed, and of Adam's fig-tree, and ufe for their 
common fait. An obfcure defcription how this lalt is 
made in the kingdom of Afem, may be fecn in Mon- 
lieur Tavernier's Voyagciy Part II. book ii. chap. xvii. 



In Ihort, this fait is difperfed over all na- 
ture ; it is treafured up in the bowels of the 
earth ; it impregnates the ocean ; it de- 
fcends in rains ^ ; it fertilizes the foil ; it 
arifes in vegetables j and from them is con- 
That chcy arc able in thofe countries to make com- 
mon fait to profic from vecrerables, ouoh- not to be 
wondered ar, fince I have been allured by a gentle- 
man of great worrh, who had the bell opportunies of 
of informing himf-If, rhat ar Dehli and Agra, capitals 
of Indoftan, fait is fo fcarceas ufually to be fold for half 
a crown a pound. We may therefore give lome credic 
to Marco Polo, when he informs us, that in the inner 
parrs of thefsire quarter of the world, in the province 
of Caindu, lying weft of Tebcth, the natives ufed falc 
inftcad of money, it being firft made up in cakes and 
fealed wiih ihe ft.imp of rhcir prince; and that they 
made great profit of this money by exchanging it with 
the neighbouring nations for gold and uu\ik. We are 
alfo told by Lu lolfus, in his Hijloria /Eihicpiai^ that in 
the country of the Abifllncs there are mountains of 
fait, the which when dug out is fofr, but foon grows 
hard^ and that this lair ferves them inftcad of money to 
buy all things. The fame is confiimed by Ramuliu, 
See his P'oyagcs hito Mthiopia^ chap. 39 and 52. 

7 Mr. Boyle, in his treatiie on the faltnefs of the Tea, 
takes notice that not only rain water, but alfo fnow 
water is very frequently impregnated with lea fdr. — In 
a violent ftorm which happened in November 1703, 
the rain which fell in fcverjl parts of Suflcx was ftrongly 
itripregnated with common fait; and Mr. Leewenhock, 
at Delft in Holland, obferved many cryftals of that falc 
left by the rain, which dafhed againft his windows during 
:fee faid ftorm Ph. Tranf. N*. 285>. p. 1530—35. 

B ; vQxtd 


veyed into animals^. So that it may well 
be efteemed the univerfal condiment of na- 
ture 'j friendly and beneficent to all creatures 
endowed with life, whetlicr it be vegetative, 
or animal. 

Naturalists, therefore, obfcrving the 
great variety of forms under which this fait 
appears, have thought fit to rank tlie fcvc- 

^ Mr. Boyle difcovercd corrmon filt in human 
blood and urine. I have oblcived ir, nor only in human 
urine, but alfo in that otdogs, horfcs, and black catjle, 
Jt may cafily be difcovcred i;i thefe, and many other 
liquids impregnated with i"", by cenain very rcj^ular and 
beautiful ft;irry figures which appear in their furface? 
after congelation, T'lefc figures 1 firll obfcrved in the 
great frort in the year 1739, and may prtjbably have 
cccafion to give a fuller account of them elicwhcre. 

The dung of fuch nnimals as Iced upon (-r.-ij or 
grain, doih alfo coniain plen[y of common lak , .»> ap- 
pears from the method of preparing fal ammoniacum 
in Egypt. This fait, as 'tis well known, is coi7)pofed 
of a volatile alcali, faturated with fpirit of comir.on fair, 
and i-? there fublinxd from foot. Now as the dung of 
camels, alVcs, and black cattle is the common fcwcl of 
Egypt,- whilll it is burning, the fire I'cpararcs from it 
a volatile alcaline file, and alfo the acid fumes of 
common fait ; thefe uniting together in the loot form 
a fal ammoniacum, which is atterwards feparated from 
it by fublimation. 

From this procefs we alfo learn, that when vegetables 
are calcined (at leaft fuch of them as have undergone 
purrcfacflion) all their muriatic f^lt doth not remain in 
their afliesj but a confiderable portion of it is feparated 
into its principles of an acid fpirit and a fixed alcaline 



ral kinds of it under certain general clafles j 
diftingulfliing it, moft ufually, into rock or 
folTil fait, fea fait, and brine or fountain lait- 
To which clafles, others might be added of 
thofe muriatic falts which are found in vege"- 
table and animal fubftances. 

These feveral kinds of common fait often 
differ from each other in their outward form 
and appearance, or in fuch accidental pro- 
perties as they derive from tlie heterogeneous 
fubflances with which they are mixed. But 
when perfedly pure, they have all the fame 
qualities j fo that chemifls, by the exadell 
inquiries, have not been able to difcover any 
elTential difference between them^. 

9 " Uc igitLir noftrA hac de re innorcfcar f-rnrentia, 
" banc incerponimus: ficiici in tora univcrfi hujus com- 
" page, una tancum eft r.qu.i, unus perfermentationem 
*' pavacas fpiricus ardens, unus mercurius, unum vobtiie 
" ial, unum acidum nirofara ac vitriolicum {A j ita, 
" pari rarionc unum idenique fal commune eft: fed 
" quum plures alienee, rerrefc, lapidofx, fulphurex, cal- 
*' cariac minerales ac pingues particulse cum hifce cor- 
" poribus connubium ine.inr, diveifi exinde emergic 
" eorum indoles ; ct fal commune idem femper obci- 
" nerec ingenium, i\ quis pingues, terrea?, calcareafque 
*' partes ab illo arcificiose fegrcgare nofTec." HoiFman 
Defalinis Hallenf. cap. viii. 

Dr. Lifter indeed (in his treatife De font. Med. An- 

glics., L. i. c. i. §iii.) takes notice that the cryftals of 

fea fait differ f jmewhat in figure from thofe of fountain 

and foflil fait i and feems to think this a great difcovery, 



Leaving therefore thefe divifions to thofc 
whom they may concern ; it will, for our 
preftrnt piirpofc, be more proper to (iiftinguiHi 
common fait after a different manner, into 
tlic three following kinds, viz. into rock or 
native fait, bay fait, and white fait. 

Bv rock fait, or native f\lt, is undcrftood 
all fait dug out of the earth, which hath 
not undergone any artificial preparation. 

Under the title of bay fait may be ranked 
all kinds of common fait extraded from the 
water wherein it is dilTolved by means of the 
fun's h::at, and the operation of the air. Whe- 
ther the water, from which it is extraded, 
be fea water, or natural brine drawn from 
wells ami fprings, or filt water ftagnating in 
ponds and lakes. 

Under the title of white fait, or boiled 
fait, may be included all kinds of common 
fait extravSlcd by codlion from the wMter 
wherem it is dilTolved ; whether this water 
be fea vvarcr, or the fait w^ater of wells, 
fountains, lakes, or rivers j or water of any 
fort impregnated with rock fait, or other 
kinds of common fait '°. 

Bnt others aJTert that this difference is only accidental 
and not conftanr,* proceeding* from fomc particular cir- 
cumftances attending the cryltal!izat:on. 

' ' The relations excra<fted from Alonfo Bar- 



The firfl of thefe kinds of fait is in feve- 
ral countries found fo pure, that it ferves for 
moft domeftic ufes, without any previous 
preparation (triture excepted.) But the Eng- 
lifh foffil fait is unfit for the ufes of the 
kitchen, until, by folution and codion it 
is freed from feveral impurities, and re- 
duced into white fait. The Britifli white 
fait alfo is not fo proper as feveral kinds of 
bay fdt for curing fifli, and fuch flefli meats 
as are intended for fca provilions, or for ex- 
portation into hot countries. So that for 
thefe purpofes we are obliged, cither wholly 
or in part, to ufe bay fait, which we purchafe 

baTecm very particular. " In the Lines — there is a fmall 
" lake upon the top of a h'ttle hill — in the middle of 
" which lake the water boils 2nd leaps up, fometimes 
" more, fon-.erimes le s; making a frightful noife. Out 
" of curiofity I went to fee ir, and found the noife and 
" motion of it fo terrible, that with reafon there be 
" very few that dare come near the mouth of ir. The 
" water is thick to that degree, that it looks more like 
" dirt than water. There is one fmall gutter where it 
" runs over • and the water that iflucth forth becomes 
" red fait as it runs along in little channels. This 
" is a mighty ftrong Lit, and has twice the virtue of 
" common fait in the working of metals, h hath alfo 
" been found to be an excellent remedy for the dyfen- 
" tery • perchance it hath in it a mixture of the red 
" alum that gives it boih colour and fpirir. Hard by 
'' this lake runs a vein of Piedra Judaica, and the 
f country thcreabours J5 full of mines of copper.'* 



in France, Spain, and otlier foreign coun- 

IHe following flieets were wrote with a 
dcfign to remove thcfc inconveniences, by 
flicwing how the fubjedls of Great Britain 
may be fupplicd with fait of their own ma- 
nufadure, fit and fuflkiciit for all their 
occafions. But in order tliat the mctliods 
lierc propofed may be better underftood, and 
that the reafonablcncfs of them may more 
fully appear, it will be neceflary to premife 
a brief account of the feveral ways of pre- 
paring bay fait as well as white fait, fo far 

" A Icngiic end a half from Julloma, in the province 
" of Pacaj^cs, there be many filt fprings that, as they 
" gufli out of the ground, in a fhort time become pure 
*' white fair, without the help of any artj and rhcy 
" incrcafc: into heaps of l.ilc unil the- winter rains dif- 
" folvc and f.vccp them aw.iy." N. B. This lad ac- 
count is conhrmcd by Herrer.i. 

*Twould be difficult to determine to which of the 
clafTcj here mentioned thofc two kinds of fait belong. 
It being uncertain, from the dcfcriprion, whether they 
nre fofhl f.lcs, or fah"^ boiled by fubtcrranean hear, or, 
bftly, flits coagulated by the heat of the fun. The 
firfl: kind is a very icr.pure fair, foeming to contain a 
large quantity of ferruginous ear(h, and probably alfo a 
mineral alculi, as may be conjctflured from its effefts 
upon metals. Ic fcems to be emitted from a fiery fpi- 
racle, much refembling that called La Salfa in tiie terri- 
tory of Modena^ which, Ramazzini informs us, con- 
tinually boiJs with melted bitumen, 



as they are come to our knowledge. For 
from this hiftory wc may form a judgment 
how far the methods now in ufe are proper, 
in what deficient, and where erroneous, and 
how they may be improved. The fame 
hiftory will aHb contain many obfervations 
and experiments which are required in de- 
monftrating the proportions in the third and 
fourth parts of this treatife. 


( ^2 ) 


The Art of preparing 


C H A P. I. 

Of Bay S a l r /';; general. 

IN relating what 1 have been able to 
colled conccining the feveral ways of 
making Talt, which now arc, or formerly 
have been in ufe, order requires that the more 
fimple methods fliould firfl be defcribed, 
and afterwards thofe which are more artifi- 
cial and compounded. It will therefore be pro- 
per, in the firft place, to relate the feveral 
methods of preparing bay fait, fo far as they 
have come to our notice ; and where the 
fubje<fl will admit of it, I fliall draw exam- 

"The art of preparing Sec. jn 

pies from the pradtice of thofe who are em- 
ployed in preparing that commodity for the 
ufe of the Britiili dominions. 

Bay fait may be divided in general into 
two kinds. Firfl:^ bay fait drawn from fea 
water; as is pradifed in France, Spain^ 
Portugal, and many other countries. Se- 
condly, bay flit extraded from fait fprings, 
ponds, and lakes ; as at the Cape de Verd 
iflands, in Africa j and at Salt-Tortuga^ 
Turks liland, and many other parts of 

The firft kind is imported, »in large 
quantities, into Great Britain and Ireland;, 
and our American colonies, and hlherics, in 
times of peace, are chiefly fupplicd with the 
latter ; but now in time of war, they have 
large quantities of bay fait from Lifbon, and 
other parts of Portugal. 

C II A P. II. 
0/ hay fait extradled by a total exhalation 
of the water wherein it was dijfohed. 

BA Y fait is prepared in a manner the 
moft fimplc and eafy, when the water 
of ponds and lakes impregnated with fait is 
totally exhaled, by the force of the fuii 

2 and 

14 The art of p)\pari)ig 

and air, and the fait is left concreted into a 
hard crufl, at the bottom of the lake or 

Of fait thus prepared wc have many in- 
Aances in fcveral parts of the world '. Thus, 
'* In the Podelian dcfcrt near the river Bo- 
*' ryilhenes is a fait lake, whofe water, by 
** tlie heat of the fun, is wafted, and turn- 
" cd to fait, like unto ice -, fo that the 
" people ride into it with horfcs and wag- 
" gons, and cut it into pieces, and carry it 
** away '. I was alfo informed by a 
worthy friend ', who long fervcd as a phy- 
fician in the Rulfun armies, that in the 
fame part of the world, viz. on the Ruf- 
fian frontiers towards Criin Tartary, he had, 

• ** Siccarur in bcu Tarcntino a-ftivis folibus, to- 
•* tiimquc flagnum in falem abit, modicum alioquin, 
*' altitudinc genua non cxccdcns. Item in Sicilia iii 
*' lacu, qui Conanicus vocitur, ct alio juxta Gclam. 
" } lorum cxtrcmitates tautum inarc'cun: ; ficut in 
" Phrygit, Cappadocia, Alpendi, ubi largius coquifur, 
" ct ufquc ad medium lacum." Plin. Natur. HijI. 
Lib. xxxi. c. vii. 

» This account is cxrra(flcd from rhc Polirti hiftorian 
Cromcrus. Sec Phil. TruripJiicns ubr. by Lrwthtrp^ 
vol. ii. p. 525. 

» Dr. Thomas Humphrey, who was phyfician to 
the army under Field iNlarlhal Lacy, in the lall cxpedi- 
dition ot' tlic Ruflians againll Crini Tarury, where he 
died ot" a contagious diftempcr. 

Bay Sal T. i^ 

in the fummer feafon, travelled over vafl 
defert plains, where grew neither tree nor 
herb, and which, for many miles together, 
were covered over with lalt-^-. 

We are told of a fdina of this kind in 
the Weft Indies, called Garci Mendoza, forty 
leagues long, and lixteen broad 5. But the 
learned Dodlor Shaw hath given us the 
moft accurate dcfcription of feveral of thefe 
falines in the kingdom of Algiers ^, which 

* The Valley of fait mentioned in fcaed Scripture, 
where David fmocc the Syrians, and Ikw i8,oo of 
them, is fuppofcd to be that nigh Tadmor: another of 
the fame kind there is nigh Aleppo. Ph. Tr. N*. 27. 

' *' The fait piis called Garci Mcrdozi, are none of 
" the moft inconfiderablc wonders of this new world. 
*' Tho:e pits arc called Garci Mcndoz,a, for their big- 
*' nefs, becaufe they be forty leagues long, and, where 
** narrowcft, fixteen broad. And alfo bccauic thac 
" (bnictimcs in the middle of that (pace are dilco- 
" vered as it were wells that hwc no bottom, and 
" great overgrown fifhcs arc fcen in them. Ic is very 
" dangerous travelling over this (pace of ground, for 
" fear of loling one's eye-fight; becaulc the grcac 
** gliftciing of the fun beams upon that place of 
", puts out one's eyes, unlet they be defend- 
*' ed with black litfiny. There is danger of life, 
*' alfo, in that journey : it having happened, that going 
" over that place, the traveller and his hurft; have both 
" been iwallowed up, leaving no manner ot mark 
*' behind cither of them." /f/onfo Barla. 

^ '* The lalf pits of Arxew lye furrounded with 
*' ffiouniains, taking up an area of about lu miles ux 

1 6 ^he Art of preparing 

in winter arc fait lakes, but dry plains in 
fummcr j at which fcafon large quantities of 
fait arc dug out of them for laic. Salinas 
of the fame kind have been taken notice of 
by travellers, in many other parts of the 
world ; but thcfc already mentioned arc 
fufficicnt for our prefent purpofc. 

C H A P. III. 
Of hay fait draiim from the brine of ponds 
and lakes and firft of fait thus prepared -^ 
in the Cape de Ferd i /lands. 

ALthoui;h the Knglilli have, for a long 
time, prepared vaft qu;uititics of bay 
f.dt in the Ca|x; dc Vcrd illands ; yet no one 

" compaf*. Tlicy appear like a large hkc in winror, 
*' but arc dry in the lunmicr, the warer being then cx- 
*' haled, and the falts left behind crylbllizcd. In dig- 
** ^ing ihcy pafs througjh different layers of this fair, 
" whcrcoKome arcan inch, others more in thickncfs, in 
*' propor:ion, I prclumr, to the falinc particles the wa- 
** tcr was impregnated with, before their refpctflivc 
" concretions. This whole area is made up of a 
" fuccclVion of fuch fimilar ftrata heaped one upon 
** another: and in the fame manner are the falinj: 
" betwixt Carthage and the Gulctta, thofc of the Shott, 
** and ot other places, cither bordering upon, or lying 
«' within the Sahara." Dr. Shaw's Travels^ p. 229. 

" Ot the like quality and flavour is the fait of 
«« the lake of Marks, and other lefler plains of the 


Bay Salt. ly 

hath hitherto given fo exadl and clear an 
account of the method of preparing it there, 
as the nature of the fubjed doth feem to 
require. The following account was col- 
le(5ted chiefly from the relations of feveral 
perfons of credit, who themfelves affifted in 
making filt at thofe iflands. 

The Cape de Verd iiles which afford fait, 
are chiefly Mayo, Bonavifla, and Sail. 
The fubjeds of Great Britain have enjoyed 
the privilege of making fait, at certain fali- 
nn? in the two firll: mentioned iflands, ex- 
cluflve of all other nations, ever fincc the 
marriage of king Charles the Second with 
the Infanta of Portugal. They do not pay 
any acknowledgment to the king of Portu- 

" fame narure. Thefe arc ufually called Sibkah, of 
** Shibkah, /. e. fdlrifli plats of ground j being com- 
*' monly overflowed in winter (ac which rime they ap- 
'* pear like (o many extenfive Jakes) but dry all Turn- 
" mer, when they naay be taken for io many bow- 
*» ling greens, prcp.ired for the turf. Some of thefe 
" Shibkahs have a hard and folid bottom, v.'iihouc 
" the leaft mixrure of grirty rr.ould, regaining the (ale 
" that lyech cryflallizcd upon them after rain. JJut oi hers 
" are of a more oozy abforbenc nature, feldom pre- 
*' fervinr^any faline incruftations upon the furface. The 
" chief fubflratum of the Shibkjh El Low-diah is, 
" like a telVelated pavement, made up of vjrious little 
'* cubes of common 1^1:/' Id.^. 230. 

C gal 

i8 The art cf preparing 

gal for this privilege ; only, of late years, he 
hath impofed a tax, paid by the Britifli cap- 
tains for every afs which they hire of the 
inhabitants to carry the fait to their buats. 
The time of making the fait, is in the dry fea- 
fon of the year j which, in thofe iflands, is 
ufually from the latter end of November, to 
the beginning of July. Thofe, therefore, 
who would load with lalt, endeavour to be 
there in the month of December, or Janu- 
ary. On the weft fide of Mayo, or May, 
they bring their fliips to anchor in a pretty 
good road, at a hundred or two hundred 
yards diftance from the lliore. As foon as 
they are on fhore, they find themfelves up- 
on a bank of light locfe fand, fifty or fixty 
yards broad. And when tliey have pafTed 
this bank, they enter upon the falina, or fait 
marfh ; which lies between the fand bank, 
and fjme fmall hills beyond it. This fali- 
na is a plain, about half a mile broad and 
a mile long, the greateft part of which is 
hollowed out in fait pits, filled at the pro- 
per feafon of the year with a ftrong brine, or 
pickle (as the failors term it) to the depth of 
about eight inches. 

Several writers aifert, that this brine 
Is only fea water, which flows through a 


B A Y S ALT* 19 

hole in the fand bank, hke a fluice, and that^ 
only at fpring tides. Thofe that I have con- 
verfed with, who made fait there, could 
give no certain information in this particular, 
only faid they had never feen any fuch fluice, 
but had obferved more brine in the fait pits 
at fpring tides, than at other times. But, as 
it is certain that there are feveral fait ponds 
in Bonavifta and Sail, which have no com- 
munication with the fea ; and that all the 
fprings nigh the filina in the iflc of May 
have a brackifli talle, and are impregnated 
with fait J and that the brine in the pits is 
much Wronger than fea water ; and that it 
is weakeft in the pits which are farther!; from 
the ^a, growing ftronger as it falls by a 
gentl^^lt-fcent into the pits which are nigher 
the ^ore ; thefe and other reafons feem to 
prove, that this flrong brine does not pro- 
ceed • from the fea, but fprings from the 
hills adjoining to the fait marfh. And this 
may polTibly be the cafe, although it fl:iouId 
be true, that the brine (lands higher in the 
pits at fpring tides, than at other times. For 
the fea water, although it may not flow into 
the pits at fpring tides, may notwithflanding 
at fuch times rife fo high, as to prevent the 
brine from draining out of them through the 
C z fand j 

20' *77y art of preparing 

fand ; and may have the fame effecl with a 
dam, and fo caufe the brine to ftand higher 
in the pits at fj^ing tides, tlian at other 
times '. 

However this be, it is certain th;it at the 
proper feafon of the year, the failors com- 
monly find all thefe pits filled witli a very 
ftrong brine, or pickle ; but fometimcs, after 
long droughts, they find it more fcarce, and 
then dig little wells, from which they fill 

' An inrtance of ihs lame kinJ I have obfcrvcd 
in fomc wells, funk nigh the fca fhore, which com- 
monly afford plenty ot frcfh watery but in very dry 
fcafons, have only held water v.hcn the tide was '\i\^ 
and were empty when the tide was our. The (prings 
which lupply thefe wells, run through a large bed of 
gravel, out or' which the w.irer flows, berwcgi i^e full 
fca an J low- water mark. When, therefore, ^le. faid 
ftrarum of gravel is ijuitc filled with water, there is 
conft.intiy plenty cf ic in the wells; but " M^ g4-eat 
droughrs, .hen the fprings arc low, all the water in 
the (aid ftratum runs beneath the bottoms of the 
v/ells, and fprings out on the f^ rtiore, a l^tlc above 
the low-water mark ; except at fuch rimes as.tfctide is 
in ; for then, the fea water has the effe(ft of a dam, and 
retains the frefh water in the flratum of gravel, all ic 
rifes higher than the bottoms of the wells; which arc 
therefore fupplied with water; until the fea returning 
bici;, gives ic liberty again to fpring out on the Oiore. 
The colliers alfo in finking a coal pit nigh Whitehaven, 
about fifty or fixry yards from the fea fhorc, when 
they had funk to the level of the fea, obferved the 
water at the bottom of the pit, to ebb and flow con- 
ftantly with the tide. 


B AY Sal T. 21 

their fait pits to the depth of eight inches. 
The bottom of thefe pits is a kind of oozy 
mud that retains the brine. The failors make 
them of various forms and fizes, accordino- 
to their fancy. Thofe who tirfl arrive cleanfe 
out as many of thefe pits from mud and dirt, 
as they have occafion for; the next (liip's 
company do the fame, and fo fucceflively, till 
all the pits are taken up ; and if any more fhips 
arrive, they are obliged to wait until thofe 
who have polTefTion of the pits are ferved. 
As the frefh water exhales from the pits, the 
fait forms into cryftals, which fink to the 
bottom of the brine. Twice a week they 
draw the fait out of the pits with rakes into 
little heaps: and after the brine is fome- 
what drained from it, they put it in barrows, 
and wheel it to their large heap, where it 
drains further, and foon becomes hard and 
dry, and fit to be put on board their fliips. 
The inhabitants of the ifland willingly af- 
fift, for hire, in making the fait ; and alfo 
provide alTes to carry it to the fca fide ; from 
whence it is conveyed, by boats, on fliip- 
board. And thus, if the weather be favour- 
able, a large fliip may be loaden with iait 
iJi a fortnight ; and frequently fooner, when 
C 3 (as 

22 'The art of preparing 

(as it often happens) the lallors, on their 
arrival, find the pits full of concreted fait. 

But, on the contrary, it fonietimes hap- 
pens, tliat the rainy fcafon continues longer 
than ufual j and tlicn, fliips have been delay- 
ed feveral nionthi) before they could get their 
loading. At other times the rains have 
come on very foon ; or the fca hath been fo 
boirterous with tornadoes (as it ufually is 
for aconfiderablc time before the rains fct in) 
that no lalt could be fhipped on board "; or 
by reafon o( teilious paira^:;es, fliips have not 
arrived in due time. And by fuch accidents, 
many iliijts have been difap[X)intcd, and 
forced to leave thefc ifiandb without their 
loading of fait 3. 

* Thefc high winds alio frequently injure :hc fair, 
by driving the fsnH arpringft ir. 

' This trade might therefore be carried on, with 
truch f^rcatcr aHvantagc, if there was a Bn:ifh UcXory 
eftabliflicd in ihefe iflanJs, who'e bufincfs it fhojlJ be 
to make (sir durin;; the whole dry fcafon, and to fell 
it to the Hritilh fubjccfh, as cheap (which they well 
might) or even cheaper, than our failors can now make 
it thcinfelvcs j which, as I am informed, is feldoni 
at a lower price than firpcnce per bufhcl. Bv this 
means our velTels would not be dinppoim.-d of their 
loading, or detained fo long as they n 'V a'c; ind the 
mariners would have nothing to do at (hefe iQes, but 
to fhip the falc on board; which might fpeedily be 
done in large lighters, ^--^va wharfs provided lor thac 


B A Y S A L T. 23 

The fait is made exadly in the fame 
manner at Bonavifta as at the ille of May. 
The falina? at both iilands are nearly of the 
fame magnitude ; that at Bonavifla alfo Hes 
beyond a fand-bank, which is about two hun- 
dred yards broad. But the brine is there 
weaker and does not kern ^ fo fafl as at the 
ille of May. And the fea being there very 
ihallow, the fliips are obliged to ride at an- 
chor at a mile diftance from tlie Ihore j fo 
tiiat the failors have there a good deal of 
trouble in dripping the fait. For thefe rea- 
fons our veflcls fcldom load there, when 
they can be fupplied with fait at the ifle of 
May. But although thefe illcs arc only 
about eighteen leagues diftant from each 
other, yet the failors have found by experi- 
ence, that the rainy fcafons fometimes begin 
feveral weeks fooner, or continue longer at 
one of thefe illands, than the other. Some- 
times, therefore, when the weather proves 
unfavourable at the iile of May, or when 
there happens to be too great a crowd of 
fhips there 5^ the failors find it more con- 

♦ To kern, is a term which the failors ufe, fip;- 
nifying to corn, or to form iir.o grains, or cryilals 
of f;ih5. Our fak-boilers call ic graining, or falcin?, 

* Tiicre are frequencly fifVccn or fixrccn fliips loading 

C 4 venient 

24 The art cf preparing 

vcnicnt to load at Honaviila. The wcatiicr 
.at tlicTc illaiids is fcldom cxccfTively liot, the 
licat of the run being tcrnjxrc(i hv frcfli 
breezes from the fea. 

c II A r in. s V. c t. ii. 

Of bay f (lit viade at Tortugai and ether place i 
in America. 

OU R American colonico have, for near 
u century pall, been fuppHed witli 
large quantities of bay ialt from Salt Tortuga, 
one of the Leeward iflands, uninhabited, fi- 
tuated nigh the coail of Caraccos on the 
Spanilh main ' ; ah'o from Turks ifland, 
vhich lies not far from Ilifpaniola * ; and 
many vefTcls freighted from North America 

wilh (alt at the nlc i! M-i- . oc;:j)L- iu\c Kti';,M! 

i}iip5 there together. 

' The D ;:ch alf ) draw hr^c qusniitic; of fjit from 
fomc ponds in Bcnjiry, an illand belonging to ihcm, 
not tar difbnt from Sah Tortuga. 

There nrc alio conlidcrabic quantities of fal: made 
in fevcral of the Cjribbcc ifl^n'^s, particularly at An- 
guill.i, Sr. Mutin's, and Sc Chriftophcr's 

* Dampier inlbrms us, that there is a pretty good rosd 
on the fouth caft fide of this ilhnd, and that the fa- 
lina lies adjoining to ir, within two hundred paces cf 
the fea j and thar, in peaceable time?, he had fccn 
ab»ovc twenty fjil of fliips in this road at one lime, 
come CO load I'alt. 


B A y Sal t. 25 

to Barbadoes, and others of the Caribbee ifles, 
were accuftomed to go from thence to thefe 
fiilt illands, and carry back a loading of fait ; 
tor which they found a market in New- 
toundland, New-England, and other Britifh 
colonies in North America. 

The Spaniards, for a long time, gave tjie 
Britilh fubjecSs no moleftation in this trade. 
But, a few years before the prefent war be- 
tween the two nations broke out, they bcgjan 
to feize allBritiih lliips laden with fait, which 
they met with nigh their fettlcments, claim- 
ing the fole property of thefe faltiflands. The 
Britilh fubjccfts, un willing to lofefo valuable a 
branch of trade, which they had long en- 
joyed without any interruption, refolved to 
maintain themlllves in it by force j therefore 
went no more in lingle lliips, but in laree 
fleets of armed vcflcls. Thefe velTels ufual- 
ly joined fleet at Barbadoes, or fome o- 
ther of the Caribbee iflands, where fcvcnty 
or eighty fail of them would fometimes muf- 
ter. Before they let forward upon the voy- 
age, they chofe a commodore, who had the 
chief command, and entered into engage- 
ments for their mutual defence; and then 
fet fail, ufually about the beginning of 
March. They commonly went to Tortu- 

26 77 1' art cf preparing 

ga; where, as foon as they arrived, they di- 
vided the fahr.a: into fevcral portions, allot- 
ting one for each iTiip, accor».ling to its bur- 
den. Each lliip's company then ufed wJiat 
diligence they could in collc(fling the fait 
that {z\\ to their (hare, and wheeling it down 
to the fhorc, thence carried it in boats on their lliip. They commonly found 
fait enough to loa.l the whole tlcet ; but it 
fome'iimes fell fhort, either when the fleet 
was too numerous, or when tJie feafon prov- 
ed uiifavourable. As foon as they had done 
Hiinping the fait, the whole fleet fet fail to- 
gether, and remained united, until they 
thought then.felves out of dan'j;er from the 
Spanifli Guanla codas j and then each lliip 
ftecred towards its intended port . 

The method of making fait at Tortuga 
and Turks ifland is much the fame as that 
pradtifed in the Cape de Verd ifles ; only, in 
the American ifles, they do not colle<ft it out 
of fmall pits, but larger ponds. The failors, 
on their arrival, often find large quantities 
of fine clear fait lying at the bottom of thefe 
ponds, from whence they rake it out. 

Many have related, as fomething very 
extraordinary, that in thefe American iflands 
thelalt kernSj or forms into grains, only dur- 

Bay Salt. 27 

ing the wet feafon of the year. But they are 
certainly miftaken who think that any fait 
is formed in thefe iflands during the continual 
rains which fall in the wetteft feafon j or 
that the brine in the ponds will not let go 
its fait, until it is diluted and made weaker 
by rains. The truth of the matter is pro- 
bably this : During the conftant rains, fuch 
vail: quantities of water fall, that the fait lakes 
overflow, and large quantities of fait are 
wafhed quite away. After the rain ceafes, 
the ponds remain filled with a weak brine, 
fo that no fait can cryftali'/c In them till 
moft of the water is exhaled -, which does 
not happen till towards the time tliat the 
rainy feafon again fets in. But in the coun- 
tries lying between the tropics, which have 
their dry and wet feafons, the rains almofl 
conftantly come on in tornadoes, or thun- 
der fliowers, which fo'r thefirft month, or fix 
weeks, only fall once a day, and fometimes 
only once in two or three days ; efpecially 
in thefe iflands, which are not fubje(5l to fuch 
long and violent rains as many parts of the 
continent lying under the fame degrees of la- 
titude. Thefe tornadoes therefore, wafh 
much fait from the furface of the earth into 
the ponds, and alfo fupply the fprings with 


28 7hc art of preparing 

water, which being impregnated with fait 
in its palTage through the earth, continually 
replenifhes the ponds with brine. But when 
the weather continues exccffively dry, thefe 
fprings are dried up, and no more brine flows 
into the ponds. Thefe tornadoes, therefore, 
do not contribute towards cryftalizing the 
fait ; but only replenilh the ponds with brine, 
which is reduced into fait by the heat of the 
fun. So that whilft the rains are moderate, 
and the water arifes in vapours, as faft as it 
falls in dews and fhowers, large quantities 
of fait are made in the ponds. But as foon 
as the rains become exceflive, and more wa- 
ter flows into the ponds than is exhaled from 
them, the brine becomes weak, and no more 
fait is extrad:ed from it. 

This account agrees well with what cap- 
tain Dampier hath related concerning the 
method of making fait at the falins in the 
bay of Campeachy. His account is as fol- 

" 3 The Salina is a fine fmall harbour for 
*' barks, but there is not above fix or feven 

' The fame author gives the following^ account of 
the weather in the bay of Campeachy, which will fervc 
to illuftrate feveral pirticubrs h-u'c taken notice of 

" The dry {tdHov^ begins m Seprember, and holds rill 
" April, or May j then comes in the wet feafon, which 

" feet 

Bay Salt. 29 

" feet water. And clofe by the fea, a lit- 
" tie within the land, there is a large fait 
" pond belonging to Cam peachy town, 
" which yields abundance of fait. At the 
*' time when the fait kerns, which is in May 

" begins with tornadoes, firft one a day, and by degrees 
" iiicreaiing till June^ and then you have fet rains till 
" the latter end of Auguft. This fvvells the rivers Co 
" that they overilow, and the Savannahs begin to be 
*' covered with water ,• and although there may be fome 
" intermillion of dry weather, yet there are ftill plenti- 
*' ful fhowers of rain, To that as the water does not in- 
" creafe, neither does it decreafe, but continues thus 
" till the north winds are (et in ftrong, and then all the 
" Savannahs, for many miles, feem to be but part of the 
'' fea. The norths do commonly fet in about 06to- 
" ber, and continue by intervals till March. — Thefe 
" winds blowing right in on land, drive the fea, and 
" keep the tides from their conltant courfe as long as 
" they laft, which is fometimes two or three days j by 
" this means the frcflres are pent up, and overflow much 
'■^ more than before, though there be Icfs rain. They 
" blow moft fiercely in December and January j but 
" afterv/ards they decreafc in llrength, and are neither 
" fo frequent nor lading j and then the frcfhes begin 
" to drain from off the ground. By the middle of Fe- 
'^ bruary the land is all dry ,• and in the next month 
*' perhaps you will fcarce get water to drink, even in 
** thofe Savannahs that but lix weeks before were like a 
" fea. By the beginning of April, the ponds alfo in 
" the Savannahs are all dried up, and one who knows 
" not liow to get water otherwifcmiy perifli for thirft. 
*' But thofc who are acquainted here, in their neceflity 
" make to the woods, and refrefli thenjfelves with v/a- 
'^ tenhatthey End in wild pines/' Vol ii. p 2. 

" or 

20 I'he art of preparing 

" or June, the Indians of the country are 
*' ordered by the Spaniards to give their at- 
*' tendance, to rake it afliore, and gather 
** it into a great pyramidal heap, broad be- 
" low, and fharp at the top like the ridge 
** of a houfe ; then covering it all over with 
" dry grafs and reeds, they fet fire to it, and 
" this burns the out fide fait to a hard black 
** cruft. The hard crufl is afterwards a de- 
" fence againft the rains that are now fet in, 
" and prefer ves the heap dry, even in the wet- 
" teft feafon '*. The Indians, whofe bufinefs 
" I have told you, is to gather the fait thus 
" into heaps, wait here by turns all the kern- 
" ing feafon, not lefs than forty or fifty fa- 
" milies at a time. — When the kerning 
" feafon is over, they march home to their 
" fettled habitations, taking no more care 
" about the fait. But the Spaniards of Cam- 
" peachy, who are owners of the ponds, do 
" frequently fend their barks hither for fait 
" to load fhips that lie in Campeachy road; 
" and afterwards tranfport it to all the ports 
" in the bay of Mexico, efpecially to Alva- 
" rado and Tompeck, two great fifhing 

* This merhod of preferving fait from rains is alfo 
prat^ifed in the Cape de Verd illands. 

" towns. 

Bay Salt. 31 

«' towns, and I think that all the inland 
" towns thereabouts are fuppliedwith it." 


Of marine bay fait prepared in Trance and 
other parts of Europe. 

THE mofl perfect works of art are 
generally the triieft imitations of na- 
ture. Hence fome have thought, that thofe 
artificial methods which have been invented 
for preparing falts, and extracting them from 
water, were borrov/ed from thofe more fim- 
ple methods by which men obferved thofe 
falts to be feparated from their watery vehi- 
cle without the help of art '. This opi- 

' " Initio folerres homines cum viderenc aquas quo- 
" rundam lacuum, natura fucci plenas, Iblis ardoribu* 
" ficcatas conrpifTari, arque ex eis fieri fuccos concre- 
" tos- verifimile eft, eos, aquas ailimiies aliis in locis 
" ir^udifTe, vei corrivafie in areas ad aliquam akitudi- 
" n d..^prefir;s, uc ipfas etiam folis calores condenfarenr. 
" t. ; . de, quia viderenc ilia rarione luccos concreros 
" lanrummodo jeftate confici pofle, nee tamen in om- 
" nibus regionihus, fed in calidis ec temperatis folum, 
** in quibus seftivo tempore raro pluit j eas quoque in 
" vafis igne lubjedlo ccquere ad fpiflirudincm ccepifle : 
*' quo mode omnibus anni temporibuSj in omnibus 
" r'^'sionibus, etiam frisiidifiimis, ex aquis iuccolis, five 
" natura five ars eas infecerir, codtis fucci concreu 
" confici poiTanc." Agricohi De le metallica^ Lib. xii. 


3 2 I'he art of preparing 

nion feems to be countenanced by the great 
refemblance that may be obferved between 
thofe plain and fimple methods of preparing 
bay fait already related, and thofe more art- 
ful methods of preparing it from fea water, 
which hrv'e long been pradifed in Europe, 
and which it will be proper in the next place 
to d. ' 

Bay ...i is not extraded from fea water 
in the colder parts of Europe ; as on the fea 
coafls of Germany, Denmark, and Sweden , 
but in places fituated in a more fouthern cli- 
mate, where the heat of the fun is more in- 
tenfe, as on the coafts of France, Spain, 
and Italy. Some marine bay fait hath alfo 
of late years been made in England, at Le- 
mington, and other parts of Hampshire, and 
in the iile of Wight j but in thofe places, 
only in the drier fummers, and then, ra- 
ther by accident than defign j it being col- 
led:ed from certain ponds which were ori- 
ginally made for heightening fea water, or 
reducing it into a ftrong brine by the heat of 
the fun, in order to lefTen the expence of 
fewel in boiling it into white falt^*. 

* In dry fummer weather confiderable quantises of 
bay fak may alio be coUeded on the Englilh fhores in 
hollows of the rocks, where the iea- water hath been left 
by the tide. 

Z The 

Bay Salt. 53 

The ponds in which this fait is made do 
nearly refemble a rude kind of falt-marfh 
defcribed by Agricola 3, in which the fea- 
Water is received from a pool into a trench ; 
and from thence derived by lluices into fe* 
veral pits dug out of the earth 3 and when it 
hath flood fome time in thefe pits, it is let 
out into others, where it ftands a certain 
time according to the heat of the weather ; 
and then is made to flow by fluices into other 
pits; till at length, being reduced to a 
ftrong brine, it is fufFered to ftagnate in pits ; 
where the fait cryflallizing, is from thence 
at proper times drawn ouf-. 

But the French marfhes, in which im* 
menfe quantities of fait are annually prepared, 
are contrived after a much more artful man- 
ner. And as they are the moft commodious 
that have hitherto been invented, it may be 
proper here to tranfcribe an account of them, 
as given by an ingenious French phylician, 
and publiflied in the l^ranfaBions of the Royal 
Society K 

3 De re metaliica^ hih. x'li. 

* A defcripiion of the HampHiire works, fee afterwards 
in Part ii. 

5 The following is the account publifhed by Lowthorp 
in his Jhridg??ient, Vol. ii. p. 363. and is almoft the fame 
verbatim with that in the Tranfa^fions^ N° 5 1. p- 1425'' 


34 ^he art of preparing 

" Plate I . AAA. is the fea. 

" I . I . The entry by which the fea water 
pafles into B B. 

^' B B. The firfl receptable, in which the 
" water maketh three turnings as you fee, 
" and is ten inches deep^. 

" 2.2. The opening, by which the firfl 
*' and fecond receptacle have communication 
" one with another 7. 

" EEF. The third receptacle is properly 
•* called the marifh. 

" dddd. Is a channel very narrow, through 
" which the water muft pafs before it enters 
" out of the fecond receptacle into the 
** third. 

"3.3 . Is the opening,by which the water runs 
" out of the fecond into the third receptacle. 
" The pricks you fee in the water throughout 
" the whole fcheme, do mark the courfe and 
** turnings which the water is forced to make 
" before it comes to hhhhj which are the 
" places where the fait is made. 

only a few particulars are here omited which do not 
relate to the fubjed:. 

^ It is in the fecond receptacle CC that the water makes 
three turnings. 

7 This opening is more conveniently made in this place 
than at * where the fea water in the firfl: re-. 



Bay Salt. 3^ 

" hhhh. Are the bed of the marifli where 
" the fait is made, and in them the water 
" muil not be above an inch and a half deep. 
" Each of thefe beds is fifteen foot long, 
" and fourteen foot large ^. 

"9999. Are the little channels between 
** the beds. 

" 8 8 8 8. Are the apertures by which the 
" beds receive the fea water after many 
*' windings and turnings. 

" When it rains the openings 2.2. 3.3, 
'^ are flopped to hinder the water from run- 
" ning into the marifh. Unlefs it rain much, 
" the rain water doth little hurt to the 
" marifh 5 the heat of the fun fufficiently 
" exhaling it, if it be not above an inch high • 
" only if it have rained very plentifully that 
" day, no fait is drawn for the three or four 
" next days. But if it rain five or fix days, 
*' the people are then neceflitated to empty 
" all the water off the beds by a peculiar 
" channel, which cannot be opened but 
" when it is low water. But it is very fel- 
" dom that it rains fo long as to conflrain 
" men to empty thofe beds. The hottefl 

ceptacle is ftrongeft than (as in the Ph, Tr.) at ** which 
feems too nigh the entry of the fea, 
* And framed en every fide v/ith wood, 

D 2 *' years! 

36 'T'bs art of preparing 

" years make the mofl fait, and in the hot- 
*' ted part of the fu miner there is fait made 
" even during night. Lefs fait in calm than in 
*' windy weather. 

" The wefl and north weft winds are the 
*' beft for this purpofe. 

"Our country people draw the fait every 
" other day, and every time more than an 
" hundred pound weight of ialt. 

"The inftruments ufed to draw the fait 
" have many fmall holes to let the water 
" pafs, and to retain nothing but the 
" fait. 

" The reddifli earth in the marifhes 
" make the fait more gray, the blueifh 
" more white. Befides if you let run in a 
" a little more water than you ought, the 
'* faltbecomes then more white, but then it 
" yields not fo much. Generally all the 
*' mariflies require a fat earth, neither fpungy 
*^ nor fandy. 

"The fait man who draws the fait muft 
*^ be very dextrous. In this ille of Rhee, 
" men there are that draw very dark fait, 
" and others that draw it as white as fnowj 
" and fo it is at Xaintonge. Chiefly care is 
" to be taken that the earth at the bottom of 
^^ the beds mingle not with the fait. 


Bay Salt. ^7 

" The fait we ufe at our tables is per- 
" fedly white, being the cream (or that fait 
" which is formed on the top of the water) 
" drawn four or five hours before the fait is 
" to be drawn. The grains of it are fmal- 
" ler than of the other. Generally the 
" fait of Xaintonge is fomewhat whiter than 
" ours. The bigncfs of our fait is the fize 
" of a pepper grain, and of a cubical 
" iliape. 

" The marifhes are preferved from one year 
" to another, by overflowing them a foot high. 

" The timber of the mariflies, if it be of 
*^ good oak, keeps near thirty years j but 
" there is ufed but little wood, all the ditches 
" and apertures, being done with ftones." . 

The foregoing defcription being in feme 
parts obfcure, and in others imperfect, it is 
neceiTary to add to it a few remarks by way 
of explanation ; that the conllruttion of the 
French falt-marili, and the method of pre- 
paring fait therein may be better underflood. 
And this feems the more neceflary, fince, 
although the above account of the French 
method of making filt hath long been pub- 
lished, yet it hath not been brought into ufe, 
neither in Great Britain nor in the Britifh 
colonies in America, 

D 3' Thosf. 

3^ ^he art of preparing 

Those therefore, who would, make a fait 
marfh, commonly chufe a low plat of ground 
adjoining to the fea, diftant from the mouths 
of large rivers, but nigh a convenient har- 
bour for boats or larger veffels. This ground 
muft be ix^^ from fprings of frefli water, and 
no ways fubjecft to land floods j and, if pof- 
fible, fliould have a clayey bottom ; it 
lliould alfo be defended from the fea either 
by banks of rifing ground, or by an artifi- 
cial mole raifed for that purpofe. 

The ground fo chofen muft be hollowed 
out into three ponds or receptacles. The 
firft, into which the fea water is ufually ad- 
mitted, may be called the refervoir. The 
fecond receptacle (which is divided into three 
diftin(5t ponds, communicating with each 
other by narrow paftages, and containing 
brine of different degrees of ftrength) may 
be called the brine ponds. The third re- 
ceptacle is furniflied with an enterance, be- 
tween which and the brine ponds there runs 
a long, winding, narrow channel j the reft 
of it is divided into feveral ftiallow pits con- 
taining a fully faturated brine,which in them is 
converted into fait, and may therefore be 
diftinguiftied by the name of the fait pits. 


Bay Salt. 39 

The firft receptacle or refervoir muft have 
a communication with the fea by a ditch 
defended on each fide with walls of brick or 
ftone J and made of fuch a depth that by it 
all the water contained in the refervoir and 
other parts of the fait marfh may flow out 
at low water ; and by it alfo the fea water 
may be admited into the refervoir at full 
fea ; fo thatj at neap tides, the marfli may 
be filled with fea water to the depth of ten 
inches in the refervoir j and confequcntly at 
higher tides, to the depth of two feet, when 
there is occafion to overflow the marfh, 
as is done in the winter feafon when no fait 
is made ; by which means the wood work 
is longer preferved from decay, and the bot- 
tom of the marih from frofl: and other 
injuries. And in order that the marfli may 
be thus overflowed when occalion requires, 
it is necefl'ary that the feveral recepta- 
cles fhould be funk fo deep that the ground 
on all fides may be fufficiently elevated to 
keep in the fea v/ater at the depth above 
mentioned. The ditch between the fea and 
the refervoir mufi; alfo be provided v/ith a 
fluice or floodgate, by which the fea water 
may be admitted, retained, or let out, and 

D 4 tl^^ 

40 The art of preparing 

the whole fait marih drained as occafion may 

The feveral ponds or receptacles muft 
not have their bottoms all upon the fame le- 
vel, but muft be made of unequal depths ; 
fo that the firft receptacle or refervoir muft 
be eight inches and a half deeper than the 
fait pits in the third receptacle. The three 
brine ponds, fttuated between the refervoir 
and the fait pits muft alfo be of unequal 
depths, that adjoining to the refervoir being 
the deepeft, and that, which is nigheft the 
fait pits, the ftialloweft ; but all of them 
muft be fhallower than the refervoir. And 
the three receptacles being thus conftru<5led j 
the water ftanding at the fame height in 
them all, and forming with its furface one 
continued plain, will be ten inches deep 
in the refervoir, when only an inch and a 
half deep in the fait pits. 

The judicious French author hath not 
given us any account of the length and 
breadth of the refervoir and brine ponds, 
but fome judgment may be formed of their 
fize from his plan of the whole work. It 
will be better to err by making them too 
large, than too fmall. In general, they 
©ught to be large enough to furnifti the fait 


Bay Salt. 41 

pits with a conflant fupply of brine fully fa- 
turated with fait j and for that purpofe it is 
neceflary to have them of different dimen- 
iions in different countries, as will be here- 
after explained. 

It is not neceffary that the refervoir fliould 
be exadly of the form which the French 
author hath defcribed, where the ground 
will better admit of another, that mav be 
chofen. And even the brine ponds, iiid 
fait pits may be made of different forms, if 
due regard be had to the general contrivance 
of the whole work. 

For the bottoms of the refervoir and brine 
ponds any kind of tough, lean clay, or 
earth, that will hold water, may ferve very 
well. The French make the bottoms of 
their fait pits of any blue or red clay they 
meet with j but in order to have a white 
clean fait, it is neceflary that thofe pits fhould 
be carefully laid with fome flrong cement 
that will retain the brine, and cannot eafily 
be broken up. As to other particulars re- 
lating to the flrudure of the French fait 
jnarfh, they are fufhciently explained by the 
ingenious phyfician whofe account is before 

The marfh being thus conflruded ; the 


42 I'he art of preparmg 

fait men, at the proper feafon of the year, 
open the floodgate when the tide is out, and 
drain off all the flagnating water ; and, if 
there be occafion, repair the bottom of the 
marfli, and cleanfe its feveral receptacles 
from mud and dirt. Afterwards, when the 
tide rifes, they, by the fame floodgate ad- 
mit the fait water into the marfh,'till it flands 
in the refervoir at the height of ten inches. 
In a dav or two, moil of the water in the fait 
pits is exhaled, and what remains in them is 
a very flrong brine. They then let in more 
fea water ; and fo take care, every two or 
three tides (oftener or fcldomer as occafion 
requires) to admit as much water into the 
refervoir as will fupply the place of that 
w^hich hath been wafted in vapours ; con- 
flantly raiflng it to the height of ten inches 
in the refervoir ; and confequently, to an 
inch and an half in the fait pits 9. AH the 
parts of the marfh are thus fupplied with 
water out of the refervoir ; but the fea water, 
which flows into the refervoir, is not con- 
fufedly mixed with the falter v/ater contained 
in other parts of the work. For, as the fe^ 

9 When the Weather is exceeding hot, and there 
are dry winds, the pits fliould be filled higher, than 
when the weather is more temperate and the air more 


Bay Salt. 43 

veral parts communicate only by mvtovj 
palTages j it is provided, that the fait \v ■• , 
flowing out of the refervoir, never 
there again -, but gently flows along till it ar- 
rives at the fecond brine pond, and after- 
wards at the third ; being forced forward by 
the fea water, and from time to time re- 
ceived into the refervoir. During this flow 
courfe, the watery fluid continually flies off 
in exhalations, and the brine is continually 
preparing for cryfliallization as it gently 
flows along, growing fl:ronger and ftronger 
the nearer it approaches to the fait pits. So 
that when it enters thefe pits, it is fully fa- 
turated with fait. And particular care is 
taken to guard the entrance of the fait pits 
with a long winding narrow channel ; by 
which means the ftrong pickle contained in 
thefe pits is prevented from returning back, 
and mixing with the weaker brine in the 
brine ponds. Care is alio taken that the 
flrong pickle in the fait pits be fpread out 
very thin to the fun and air, with a large fur- 
face 3 by which means the watery vapours 
more quickly exhale from it, leaving the fait 
concreted into cryftals. Thefe the fait men 
carefully draw out, and oftentimes difpofe into 
large pyramidal heaps j which they thatch 


44 ^^^ ^^^ of preparing^ Sec. 

over with flraw, and fo preferve them from 
the injuries of the weather. Thus, at a 
fmall expence and trouble a fait is prepared 
which is found extremely fit for all domeftic 
ufes 5 and thus France is alfo furnifhed with 
a very profitable article for exportation into 
foreign countries. 

The French have fo many works of this 
kind, that an ingenious author of that nation 
affirms, that, in favourable feafons, as much 
fait is fometimes made in a fortnight as is 
fufficient for the whole annual confumption 
of that kingdom, and of all thofe other nations 
who purchafe much more of it than the 
French confume themfelves ; but after a 
rainy fummer there is often a fcarcity of fait, 
and the price of it increafes. 



PART ir. 

The A R T of preparing 



Of White Salt in general. 

LT HOUGH, in warm climates, 
lalt is made, with the greateft eafe, 
and at tlie leaft expence, by the heat of the 
fun, after tlie methods ah-eady defcribed; 
yet, in leveral countries, where bay fait 
might be conveniently made, they prepare 
all their fait by culinary fires. Thus in 
Auflria, Bavaria, and many other parts of 
Germany, and alfo in Hungary, and even 


'46 ^e art of preparing 

in fome parts of Italy \ they conftantly boil 
the water of their fait fprings into white fait ^ 
either becaufe the cuftom of making fait in 
that manner hath long prevailed, and lefs 
expenfive methods have not been thought of; 
or elfe, becaufe in thofe inland countries, they 
have no great occafion for very flrong fait 
to cure provifions, and efteem white fait more 
beautiful and fitter than bay fait for the ufes 
of the table 3 or laftly, becaufe, in thofe coun- 
tries, they are unwilling to wafte any of their 
brine, which could not be converted into 
fait by the heat of the fun during the winter 
feafon. But in other parts of Europe, as in 
Britain, and in the northern parts of 
France and Germany, an erroneous opinion 
long prevailed, that the heat of the fun was 
not there fufficiently intenfe, even in the 
fummer feafon, to reduce fea water, or brine 
into bay fait. And all arguments would 
probably have been infufficient to remove 
this prejudice from the Englifli, had not the 

* ^' Tales falinae extant in Volaterrano, ubi colleda 
" aqua e puteis akiffimis, et in cortinis plumbeis decodta, 
" in faletn paulatim denfatur, qui omnium albiflimus 
" ac tenuis, in lautis menfis eligitur : unicum hodie 
" illi civitati vedigal." Baccius, De Therm. L. v. 
Cap. 4. 


White Salt. 47 

contrary been fully proved by experiments. 
which were firft accidentally made in Hamp- 
fhire. However, the method of making 
fait by coftion will probably flill continue 
to be pradlifed in Britain ; as the fait fo pre- 
pared is for feveral ufes preferable to 
bay fait j and when prepared after a par- 
ticular manner, is preferable to common bay 
fait, even for curing provilions, as the 
practice of the Hollanders doth fufficiently 
teflify. So that the due and right prepara- 
tion of white fait feems very deferving of 
the notice and regard of the public. 

White fait, as it is prepared from va- 
rious faline liquors, may therefore be dif-^ 
tinguifhed into the following kinds *. viz. 

I . Marine boiled fait j which is extra6led 
from fea water by coftion. 

' Under the heads here given may be included all 
Jcinds of white fait now in ufej although other kinds 
difFering at leafi: in preparation from thofe here mentioned 
may probably be ufed hereafter ■ as the refined white 
lalt recommended in the fourth part of this v.-ork« 
Other kinds have alfo formerly been in ufe, as fait boiled 
in earthen vefiels by the heat of natural baths, of which 
George Agricola gives the preparation, Lib. xii. De re 
TTietallica, Alfo that kind of U\i l"kid to be made in Lor- 
rain, by cafting fait water upcn hot plares of iron, as 
Monfieur Pomsc relates, Hlflcirc da Drogues^ Lib. iii. 
C. 13. 

2; Brine 

48 ^he art of prepamig 

2. Brine or fountain fait, prepared by 
codion from natural brine whether of ponds 
and fountains, or of ponds, lakes, and 

3. White fait prepared from fea water, 
or any other kind of fait water, iirfl heighten- 
ed into a flrong brine by the heat of the fun, 
and the operation of the air. 

4. White fait prepared from a ftrong 
brine or lixivium drawn from earths, fands, 
or flones impregnated with common fait. 

A yet more rude method of preparing fait was pradifed 
by the ancient Gauls, Germans, and Spaniards, as Ta- 
citus and others teftify. The fait by them prepared 
might have fome pretenfions to the name of a boiled 
fair, although it was not white, but black. Pliny gives 
the following account of it. " Gallije, Germaniaeque, 
ardentibus lignis aquani falfim infundunt. — Quercus 
optima, ut qux per fe, cinere lincero, vim falis reddat : 
alibi corylus laudatur ; ita, infufo liquore, carbo etiam 
in falem vertitur. Quocunque ligno confit, fal niger 
eft." Hiji. Nat. L. x.vxi. c. 7. 

Dodlor Beal obferves, that " in Varro's days, it was 
** the reproach of our Trans Alpines (who dwelt much 
*' farther towards the fouth than we do) that on the 
" Rhine, Nee vitis, nee olea, nee poma nafcerentur^ 
*' ubi falem nee foffilem, nee maritimum haberent ; 
" fed ex quibufdam lignis combuftis, carbonibus falfis, 
*' pro CO uterentur." Varro, dc re ruji. L. i. c. 6. 
"=' — The world (remarksthat judicious phyfician) is much 
" amended fince thofe days, on this fide the A'pes. 
*^ And the Englifh may yet be minded to proceed as far 
" as they can, to remove the reproach, at leaft for 
«//«?>, w'me^ and fait:* Ph. Tr. N°. 103, p. 48. 

5. Re- 

Whit E Salt. 49 

5. Refined rock fait j which is boiled 
from a folution of foffil fait in fea water, or 
any other kind of fait water, or pure water. 

6. Lastly, fait upon fait ; which is 
bay fait diflblved in fea wsLter, or any 
other fait water, and with it boiled into 
white lalt. \; ''■ \ ' ■ - ' 

Under thefe hedds hiay b(^^ ranked the 
feveral kinds of boiled fait now in ufe: ''It 
will be proper therefore to treat the prepai'a- 
tlon of thefe feveral kinds of common fait, 
in the fame order in which they iare h^re 
enumerated. --'^ --•-•' .^yrr-ivo : ;■: r— i 

C H A P. n. SEC T. I. 

Of fait boiled from fea wafer, 

TH E method of extradling fait from 
fea water by codlion is only pra(flifed 
in places where great plenty of fuel can be 
had at a very low price j and therefore is 
ufed in few countries except on thofe parts 
of the Britifli coafts which moft abound with 
pit coal, as at North and South Sheilds, 
Blyth, and other places in Northumberland 
and Durham ' ; ' from whence this fait is ex- 

* In thefe two counues ihey have about two hundred 

E ported 

50 ^he art of frepanng 

ported in large quantities, under the name 
of Newcaftle fait, to London and other 
parts of England, and to Denmark, Nor- 
way, and other northern countries. Much 
of this fait is alfo made on the coafts of Cum- 
berland ; and at feveral works fituated on 
the Firth of Forth, and at Air and Saltcotes 
in Scotland 5 at all which places the worft 
of their coals are applied to this ufe. 

The works for making this fait are vari* 
oufly conftrudled in various places ^ thofe 
feem befl contrived which are made after the 
following manner. 

At forne convenient place near the fea 
fhore is eredled the faltern ^. This is a long, 
low building, confifling of two parts ; one 
of which is called the fore-houfe, and 
the other the pan-houfe or boiilng houfe. 
The fori -houfe ferves to receive the fuel, 
and cover the workmen ; and in the 
boiling houfe are placed the furnace, and 
pan in which the fait is made. Sometimes 
they have two pans, one at each end of th& 
faltern j and the part appropriated for the 
fuel and workmen is in the middle. 

pans at work, in which they annually prepare eleven or 
twelve thoufand tons of fak. 
* See Place II. Fig. i. 


White Sal T. 51 

The furnace 3 opens into the fore-houfe, 
by two mouths, each of which is a mouth 
to the afh pits. To the mouths of the 
furnace, doors are fitted j and over them a 
wall is carried up to the roof, which divides 
the fore-houfe from the boiling-houfe, and 
prevents the dull of the coal, and the aflies 
and fmoke of the furnace from falling into 
the fait pan. The fore-houfe communicates 
with the boiling houfe by a door placed in 
the wall which divides them. 

The body of the furnace "^ confifts of two 
chambers divided from each other by a brick 
partition called the mid-feather j which from 
a broad bafe terminates in a narrow edge nigh 
the top of the furnace ; and by means of 
fhort pillars of caft iron eredted upon it, fup- 
ports the bottom of the fait pan 5 it alio fills 
up a confiderable part of the furnace, which 
otherways would be too large, and would 
confume more coals than, by the help of 
this contrivance, are required. To each 
chamber of the furnace is fitted a grate, 
through which the alhes fall into the afh 

J See a reprefentation of the front of the furnace 
Plate III. Fig. 2. 

+ See Plate III. Fig. 2. 

E 2; pits; 

52 l^he art of preparing 

pits 5. The grates are made of long bars of 
iron, fupported underneath by ftrong crois 
bars of the fame metal. They are not con- 
tinued Jtg the fartheft part of the ftirnace, it 
being unnecefTary to throw in the fuel fo far j 
for the flame is driven from the fire on the 
grate to the farthefi part of the furnace j and 
from thence palles together with the fmoke, 
through two flues into the chimney ^j and 
thus the bottom of the fait pan is every where 
equally heated. - ,, ',' "~, 

The lalt pans 7 are made or an oblong 
form, flat at the bottom, with the fides 
erecfled at. right angles ^ the length of 
fome of thefe pans is fifteen feet, the 
breadth twelve feet, and the depth fix- 
teen inches, but at different works they are of 
different dimenfions ^. They are common- 

5 At feveral fait works, particularly at moft of thcfc 
nigh Newcaille, they have neither grates, nor afli pitsj 
but make their fires upon hearths. 

^ See Plate IV. Fig. i and 2. 

7 Wherethey make their fires on hearths, the chitnneys 
are ufually carried up at the end of the pan adjoining to 
the fore-houfe. 

* At many works they ufe pans of a much lefs fize 
than here defcribed. But thofe ufcd at Shields and 
other places nigh Newcaftle are much larger, being 
commonly twenty one feet long, twelve feet and a half 
bread, and fourteen inches deep, being the largefl fait 
pans uled any where in Great Britain. 

W H I T F Sal Ti--n 53 

!y made of plates of iron 9, joined together 
with nails, and the joints are filled with a.^ 
ilrong cement. Within the pan five or fix 
ftrong beams of iron are fixed to its oppofite 
fides, at equal diflances, parallel to each 
other and to the bottom of the pan, from, 
which they are diftant about eight inches. 
From thefe beams hang down flrong iron 
hooks, which are linked to other hooks or 
clafps of iron firmly nailed to the bottom of 
the pan -, and thus the bottom of the pan is 
fupported and prevented from bending down 
or changing its figure ^°, 

The pan, thus formed, is placed over 
the furnace, being fupported at the four cor- 

9 The Plates moft commonly ufed are of malleable 
iron, abouc four feet and a half long, a foot broad, 
and the third of an inch in thicknefs. The Scotch pre- 
fer fmallcr plates, fourteen or fifteen inches fquars. 
Several make the fides of the pan, whefe they arc not 
expofed to rhe fire, of lead j thofe parts, when made of 
iron, being found to confume fall in rufb from the fteam 
of the pan. Som.e have ufed plates of caft iron, five or 
fix feet fquare, and an inch in thicknefs ,• but they are 
very fubjefl to break, when unequally heated, and 
fliaken (as they frequently are) by the violent boiling of 
the liquor. The cement moft commonly ufed to fill 
the joints, is plaifter made of lime. 

»^ See Plate III. Fig. 2. and Plate V. Fig. 2, from 
'Agricola ; in which the bottom of the pan is fupported 
by v/ood beams fixed at a confiderable height above the 
fait pan j as isftill pra(5tifedat feveral fait works, 

^ E 3 ners 

54 ^^ ^i of preparing 

ners by brick work j but along the middle, 
and at the fides and ends, by round pillars of 
cafl iron called taplins, which are placed at 
three feet diftance from eaCh other, being 
about eight inches high, and at the top, 
where fmalleft, four inches in diameter. By 
means of thefe pillars the heat of the fire 
penetrates equally to all parts of the bottom 
of the pan, its four corners only excepted. 
Care is alfo taken to prevent the fmoke of 
the furnace from paffing into the boiling- 
houfe, by bricks and ftrong cement, which 
are clofely applied to every fide of the fait 

Between the fides of the pan and walls 
of the boiling-houfe there runs a walk '* five 

" In fome places, as at Blyth in Northumberland, 
befides the common fait pans here defcribed, they have 
a preparing pan placed between two file pans, in the 
middle part of the building, which in other works is 
the fore-houfe. The fca water being received into this 
preparing pan, is there heated and in part evaporated 
by the flame and heat conveyed under it through flues 
from the two furnaces of the fait pans. And the hot 
water, as occafion requires, is conveyed through troughs 
from the preparing pan into the fait pans. Various other 
contrivances have been invented to lefTen the expence 
of fuel ; and feveral patents have been obtained for that 
purpofe J but the fait boilers have found their old me- 
thods the moft: convenient. 

V- See Plate If I. Fig. z. 


White Salt: ^ 

or fix feet broad, where the workmen 
ftand when they draw the fait, or have any 
other bufinefs in the boiling-houfe. The 
fame walk is continued at the end of the pan 
next to the chimney > but the pan is placed 
clofe to the wall at the end adjoining to the 

The roof of the boiling-houfe is covered 
with boards faflned on with nails of wood, 
iron nails quickly mouldering into ruft. In 
the roof are feveral openings, to convey off 
the watery vapours j and on each fide of it, 
a window or two, which the workmen open 
when they look into the pan whilfl it is 

Not far diftant from the faltern, on the 
fea-fliore, between full fea and low water 
marks, they alfo make a little pond in the 
rocks, or with ftones on the fand, which 
they call their fump. From this pond they 
lay a pipe, through which, when the tide 
is in, the fea water runs into a well adjoin- 
ing to the faltern ; and from this well they 
pump it into troughs, by which it is convey- 
ed into their fhip or ciftern, where it is llored 
up until they have pccafion to ufe it. 

The ciftern is built clofe to the faltern, 
E 4 and 

J 6 ^he art of preparing 

and '3 rnay be placed moft conveniently be« 
tween the two boiling-houfes, on the back 
fide of the foreiide of the fore-houfe ; it is 
made either of wood, or brick and clay ; it 
fometimes wants a cover, but ought to be 
covered with a fhed, that the fait water 
contained therein may not be weakened by 
rains, nor mixed with foot and other impu- 
rities. It fhould be placed fo high that the 
water may conveniently run out of it, through 
a trough, into the fait pans. 

Besides the buildings already mentioned, 
feveral others are required j as ftore houfes 
for the fait, cifterns for the bittern, an 
office for his majeily's fait officers, and a 
dwelling houfe for the fait boilers. 

All things being thus prepared ; and the 
fea water having flood in the ciftern, till the 
mud and fand are fettled to the bottom, it is 
drawn off into the fait pan. And at the 
four corners of the fait pan, where the flame 
does not touch its bottom, are placed four 
fmall lead pans called fcratch pans, which, 
for a fait pan of the lize abovementioned, 
are ufually about a foot and an half long, a 

?' Where there is only one fait pan the ciftern is 
ufually placed at thp end of the boiling-houfe j as in 
Plate II. Fig. 2. " ' 


White Salt. ^j 

foot broad and three inches deep, and have 
a bow or circular handle of iron, by which 
they may be drawn out with a hook, when 
the liquor in the pan is boiling. 

The fait pan being filled with fea water, a 
ftrong fire of pit coal is lighted in the furnace ; 
and then, for a pan which contains about 
fourteen hundred gallons, the fait boiler takes 
the whites of three eggs ^*, and incorporates 
them well with two or three gallons of fea 
water, which he pours into the fait pan while 
the water contained therein is only lukewarm ; 
and immediately ftirs it about with a rake, 
that the whites of eggs may every where be 
equally mixed with the fait water. 

As the water grows hot, the whites of 
eggs feparate from it a black frothy fcum, 
which arifes to the furface of the water, and 
covers it all over. As foon as the pan begins to 
boil, this fcum is all rifen, and it is then time 
to fkim it off. 

The moft convenient inftruments for this 
purpofe are ikimmers of thin afh boards fix 
or eight inches broad, and fo long that they 

'^ Inftead of whites of eggs, at many falterns, as at 
moft of thofe nigh Newcaftle, they ufe blood from the 
butchers, either of fheep or black cattle, to clarify the 
ii:a water. And at many of the Scotch falterns they do 
pot give themfelyes the trouble of clarifying ir. 


c8 *7^^ ^^i ^f preparing 

may reach above halfway over the fait pan '^* 
Thefe fkimmers have handles fitted to 
them; and the fait boiler and his affif- 
tant^ each holding one of them on the op- 
pofite fides of the pan, apply them fo 
to each other that they overlap in the 
the middle, and beginning at one end of the 
pan, carry them gently forward together, 
along the furface of the boiling liquor to the 
other end j and thus without breaking the 
fcum, colledl it all to one end of the pan, 
from whence they eafily take it out. 

After the water is fkimmed, it appears 
perfecflly clear and tranfparent, and they con- 
tinue boiling it brifkly, till fo much of the 
frefh, or aqueous part is evaporated, that 
what remains in the pan is a flrong brine 
almoft fully faturated with fait, fo that fmall 
faline cryflals begin to form on its furface ; 
which operation, in a pan filled fifteen inches 
deep with water, is ufually performed in five 

The pan is then filled up a fecond time 
with clear fea water drawn from the ciftern, 
and about the time when it is half filled, the 

«s See Plate VI. Fig. 3. 


White Salt. ^ 

fcratch pans are taken out, and being emptied 
of the fcratch found in them, are again placed 
in the corners of the fait pan. The fcratch 
taken out of thefe pans is a fine white calca- 
rious earth found in the form of powder, 
which feparates from the fea water during its 
codtion before the fait begins to form into 
grains. This fubtile powder, is violently 
agitated by the boiling liquor, until it is 
driven to the corners of the pan, where the 
motion of the liquor being more gentle, it 
fubfides into tlie fcratch pans placed there 
to receive it, and in them it remains undi- 
flurbed, and thus the greateft part of it is 
feparated from the brine. 

After the pan hath again been filled up 
with fea water, three v/hites of eggs arc 
mixed with the liquor, by which it is cla- 
rified a fecond time, in the manner before 
defcribed j and it is afterwards boiled down 
to a ftrong brine as at firfl ; which fecond 
boiling may take up about four hours. 

The pan is then filled up a third time 
with clear fea water ; and after that a fourth 
time ; the liquor being each time clarified 
and boiled down to a ftrong brine as before 
related ; and the fcratch pans being taken 


6o T^Jje art of preparing 

out and emptied every time that the pan is 

filled up. 

Then, at the fourth boiling, as foon as the 
cryftals begin to form on the furface of the 
brine, they flacken the fire and only fufier the 
brine to fimmer or boil very gently. In this 
heat they conftantly endeavour to keep it all 
the time that the fait corns or granulates, 
which may be nine or ten hours. The fait 
is faid to granulate, when its minute cryftals 
cohere together into little mafiTes or grains, 
which fink down in the brine aijd lie at the 
bottom of the fait pan. 

When mofi: of the liquor is evaporated, 
and the fait thus lies in the pan almoft dry 
on its furface, it is then time to draw it out. 
This part of the procefs is performed by 
raking the fait to one fide of the pan into a 
long heap, where it drains a while from the 
brine, and is then filled out into barrows or 
other proper vefiels, and carried into the fi:ore 
houfe, and delivered into the cuftody of 
his majefty's officers. And in this manner 
the whole procefs is performed in twenty 
four hours J the fait being ufually drawn 
every morning '^ 

^^ From a pan fourteen feet and a half long, eleven 
feer and an half broad, and lixceen inches deep conrain- 


Wh I t e S alt. 6 1 

In the ftore-houfe the fait is put hot into 
drabs '^ which are partitions like ftalls for 
horfes, lined on three fides and at the bottom 
with boards, and having a Hiding board on 
the fore fide to put in or draw out as occalion 
requires. The bottoms are made fhelving, 
being highefl at the back fide, and gradually- 
inclining forwards i by which means the 
faline liquor, which remains mixed with the 
fait, eafily drains from it ; and the fait in 
three or four days becomes fufiiciently dry, 

ing about one thoufand three hundred and five gallons^ 
they draw from fifceen to twenty bufhels of falc every 
day, each bufliel weighing nky fix pounds. 

At the falc works at Shields and other places in Nor- 
thumberland and Durham they only draw their puns five 
times in a fortnight, filling them up feven or eight times 
in each procefs, and from each pan commonly obtain 
fifty fix bufliels of ialt at a draught. They reckon that, 
in making a ton or forry bufliels of (alt, they confumc 
three chaldrons of fmall pit coal, which cofl them fix- 
teen fhillings and fix pence j and p-iy to the falc boilers 
for their labour four lliillings 

'7 In fomc places, inftead of thcfe drabs, they ufe 
cribs, which 'are veflels like hay-racks, broad at the 
top, and tapering to a fliarp bottom, v/i:h wooden ribs 
on each fide placed fo clofe that the fait cannot 
eafily fall through them. At o:her works, as at Leming- 
ton, they ufe wcv.Mcn troughs v.'ich holes at the bottom, 
through which runs the luperfiuous 1 quor into other 
troughs placed below to receive it. In other places 
they draw the falc into barrows, or wicker bafkers, out of 
which the better liquor eafily drains, as v/iU be explained 


62 ^he art of preparing 

and is then taken out of the drabs, and laid 
up in large heaps, where it is ready for 

The faline liquor which drains from the 
fait is not a pure brine of common fait, but 
hath a fliarp and bitter tafle, and is there- 
fore called bittern ^^ j this liquor at fome 
works they fave for particular ufes, at others 
throw away. A confiderable quantity of 
this bittern is left at the bottom of the pan 
after the procefs is finifhedj which, as it con- 
tains much fait, they fufFer to remain in the 
pan, when it is filled up with fea water. But at 
each procefs this liquor becomes more fliarp 
and bitter, and alfo increafcs in quantity j fo 
that, after the third or fourth procefs is finifhed, 
they are obliged to take is out of the pan : 
otherwife it mixes in fuch quantities with the 
fait as to give it a bitter tafte, and difpofes it 
to grow foft and run in the open air, and 
renders it unfit for domeftic ufes. 

After each procefs there alfo adheres to 
the bottom and fides of the pan a white 
iloney cruft of the fame calcarious fubftance 

*^ The marine bitrern is a ponderous liquor, ex- 
ceeding clear, and almufl: as colourlefs as pure watery 
whereas the bittern drawn from fome falc If rings 1% of a 
brownifli colour, 


White Salt. 6% 

with that before coUeded from the boil- 
ing liquor. This the operators call flone 
fcratch, diftinguifhing the other found in 
the lead pans by the name of powder fcratch. 
Once in eight or ten days they feparate the 
ftone fcratch from their pans with iron picks, 
and in feveral places find it a quarter of an 
inch in thicknefs'^. If this ftony cruft is 
fuffered to adhere to the pan much longer, 
it grows fo thick that the pan is burnt by 
the fire, and quickly wears away. 


Mifcellanious obfervations and cautions relating 
to the foregoing procefs. 

I , X N the foregoing procefs the fait be- 
jL gins to grain, or /orm into cryflals 
immediately after the brine is brought to 
fuch a flrength as to be fully fatiated with 
fait J for if the evaporation be continued any 
further, the water remaining is not fufficient 

»9 At Hall in Saxony they cleanfe their falc pans from 
the ftone fcratch thrice a week, by removing them from 
off the furnaces, and fecting them upon one fide, then 
blaming flra win them, by which the fcratch is loofened, 
and falls off by beating the bortonj and fides oi the pan 
v/ith a mallet, 


64 '^he art of preparing 

to keep all the fait dilTolved, which there-* 
fore begins to feparate from it, and to con- 
crete into cryflals. 

2. Water is fully fatiated with com- 
mon fait, wlien each pound of it ayerdupois 
contains about fix ounces of fait. For it 
hath been found by experiments-, that fo 
much fait and no iriOre can be dilTolved in 
pure water'. 

3. For the better underftanding of the 
foregoing procels it ought be confidered 
that common fait, as well as the lixi- 
vial fait of vegetables, and feveral others 
of the more foluble kinds of falts, are dif- 
folved in nearly equal quantities In cold wa- 
ter, and water of a boiling heat. Whereas 
tartar, nitre, feveral kinds of vitriol, and 
other falts, which are lefs foluble, or require 
a large proportion of cold water to diffolve 

^ Count Marfilli in his Hijioire phyf. de la mer^ Par- 
tic ii. pag. 29. aflares us diac a pound of fca water can 
only diffolve an ounce, two drachms, and ten grains of 
faltj but in this and in feveral inftances his ^xperimenrs 
have not been made with fufficient accuracy. His error 
in this experiment feems to have aroie from ufing the 
reliduum of Tea water evaporated tea drynefs, which he 
miftook for pure marine laic j and obferving feme of ic 
to fubfide and remain undiffolved, he concluded than 
the fea water was fully faturated. More exacftncf^ 


WhiteSalt. 6j 

them, may be dilTolved in much greater 
quantities by hot than by cold water 3. 

4. The marine fait is therefore only fe* 
parated (at leaft in any confiderable quanti- 
ties) from the water in which it is dilTolved, 
during the time that the water exhales from 
it in vapours. Moil of the fait being retain* 
ed in cold water, which was diffolved in it 

might be expcded from the illudrious Mr. Boyle, al- 
though he only allows that one part of filt may be dif- 
folved in five parts of pure water. Boerhaave comes 
nearer to the truth, when he affirms that pure water is 
fully fatiated, when the proportion of fair is to that of 
the water as one to three and a quarter. But Dr. Fred. 
Hoffman afll-rts, upon the authority of exaifler experi- 
ments, that a pound averdupois of pure water will dif- 
folve fix ounces of fait ; which is in the proportion of 
one part of fait to two and two thirds of water. See PIofF- 
man Defalinis Hallenf. C. ii. & Obf. phvf. chem. Lib ii. 
Obf 17. 

5 Dr. Petit, in his moft ingenious difcourfe on the pre- 
cipitation of common fait in refining of falr-petre, ob- 
ferves, that twenty four drachms of the water of the 
Seine made fcalding hot (tres chaude) diffolved abouc 
eight drachms and an half, or at moft nine drachms of 
marine falt^ and that none of this fait was precipitated 
from the water when cold, no not in the coldeft winter 
during the time of the hardeft froft • and that the fame 
quantity of boiling water did not diiToIve more thatt 
nine drachms and an half of fea fait. 

But on the contrary, water of different degrees of 
heat according to the temperature of the air, at different 
feafons of the year, retained very different quantities of 
falc-petre diffolved therein. For he obferved, thar, during 

F whilft 

^^ The art of preparing 

wWld hot^. So that in the foregoing prc- 
cels it is necelTary to continue the evapora- 
tion, until the water which keeps the fait dif- 
iolved is in a great manner exhaled. 

5. But in the cryftalization of vitriols, 
nitre, and other lefs foluble falts, they pro- 
ceed in another way, and boil the folutions 
of thefe falts to a pellicle, or until the hot 
water is faturated with them. Thefe folu- 
tions are then drawn out into proper veffels, 
and when cool are greatly overcharged with 
fait, moil of which therefore Ihoots into 

the winter feafon, in ahard froft, twenty four drachms of 
the water of the Scint; only retained dilVulved three 
drachms of niircj but in ilmiiner the faine quantity of 
water of the ianie tcn)pcrature with the external air dil- 
folved ten drachms of niticj and above feventy drachms 
of nitre niight be diirdved in the fame quantity of wa- 
ter made boiUng hot. 

In all thefe experiments the quantity of falts difiblved 
was fomevvha: different according as the water of the 
Seine contained more or lefs of a certain fubtile earth, 
which he calls Terre fine holmre. See the faid difcourfe 
in the Memoir es de l^ Acad Royal dcs Scien. pour f Ann. 

^ If nine drachms of fait may be diffolvcd in a cer- 
tain quantity of cold water, and only nine drachms and 
an half in the fame quantity of boiling water, then a 
fully faturated brine of the heat of boiling water will, 
when cold, only let fall the nineteenth part of the fait ic 
contains, if no water exhales from it while it is cooling. 

6. In 

White Salt. 67 

6. In the procefs of boiling fea-falt great 
errors are often committed by continuing the 
evaporation too long, and fo reducing a con- 
fiderable quantity of the falts of the bittern 
into a folid form, along with the marine 

7. The cryflals of fait made by the fore- 
going procefs are mofl of them broken during 
the codtion, and concreted together into ir- 
regular clufters or grains, from which it is 
difficult to determine the natural figure of 
the cryftals of common fait. 

8. But when, by a very gentle exhalation 
of water from common fait, it is fuffered 
to flioot into its true form, its cryflals are 
found of a cubical figure, of various fizes ; 
and many of thefe fmaller cryftals are united 
together into hollow pyramids with a fquare 
bafe. Thefe pyramids are truncated, being 
not finifhed at the top, but having there 
fixed a cube of ialt of a more than ordinary 
bignefs K 

5 The falr-perre boilers, who in France preferve for 
domefVic ufes the common fait, which they exrrad in 
refining of nitre, obferve, that during the time that 
the common fait precipitates from their lixivium, it 
ought to be boiled as gently as poflible in order to have 
large and beautiful grains of common fjlt. For by this 
gentle codion, fay they, the grain forms better, and is 

F 2 9. It 

68 ^he art of prepariiig 

9. It ought alfo to be remarked, that, va 
the tbregoing procefs, moil: of the faline 
cryftals are formed nigh the furface of the 
brine, from whence the water is evapo- 

10. A SLOW and gentle evaporation of 
the water gives the fait Hberty to form into 
large grains. 

1 1. But violent andhafty boiling breaks 
the tender cryftals of fait and makes the 
grain fmall. 

12. The fait is alfo made of a fmall grain 
by ftirring the brine about during the granu- 

13. If the evaporation be llowly per- 
formed, the faline cryftals concrete into larger 
clufters, the longer they remain in the pan. 

14. Those therefore, who would have 
fait of a large grain, muft evaporate the brine 
very gently, while the fait is forming j and 
muft fuffer it to lie a long while in the pan, 
and muft not draw it out until it all be 

better nouriflied. For then the grains are not bruifed 
fo violently againft each other, and againftthe fides of 
the cauldron, as when the lixivium is made to boil 
more brilkly. See the above mentioned difcourfe of 
Dr. Petit. 
^ See Ph, Tfanf, Abr, by Lowthorp, vol. II. p. 358. 

15. But 

White Salt. 69 

15. Btjt thofe who defire to have their 
fait of a fmall grain, boil it pretty haftily, 
and draw it out of the brine as foon as a con- 
liderable quantity of it is fallen to the bottom 
of the pan, often drawing the pan five or fix 
times during the time that the fait is forming; 
as will be explained hereafter in treating of 
the method of preparing bafket fait. 

16. The fait made by a gentle evapora- 
tion of the water is not only of a larger 
grain, but alfo firmer and clearer, and of 
a more fharp and pungent tafte than that 
which is made with hafty fires. 

17. Moreover, the fait boilers unani- 
moufly agree, that much of their fait is wafted, 
when violent fires are ufed towards the end 
of the procefs, whilft the fait is forming, 
which they call the time of faking ; fo that 
when they boil violently at that time, they 
do not obtain fo much fait, as when they ufe 
more flow and gentle fires ^ 

18. They alfo obferve, that, when vio- 
lent fires are ufed during the time of faking, 
the quantity of bittern is confiderably greater 
than when gentle fires are applied, 

7 This is confirmed by Dr. Plot, Dr.Hoffinan and many 

F 2 Fur* 


70 The art cf preparing 

19. Furthermore, when they ufe too 
hafly fires, large quantities of fait often ad- 
here to the bottom of the pan ; and the ope- 
rators then fay that the fait is burnt. 

20. The fait which thus adheres to the 
pan, and all lalt grained with violent fires, 
is found unfit for preferving provifions. Such 
fait will not endure to be long expofed to 
the open air, but greedily imbibes the aqueous 
moifture, and with it runs into brine ; for 
which reafon, the operators fay, that it is not 
well cleared from the freih ^. 

The inconvenience of quick fires is fully 
proved by the pradice of the Chefhire falt- 
boilers 5 who, about a hundred years ago, 
made ufe of pans which only held about 
forty eight gallons of brine, and afterwards 
pans, which held twice that quantity, being 
fomewhat more than a yard fquare and fix 
inches deep^, and fo hurried on their work 
that in the fpace of two hours they ufually 
boiled one of thefe pans of brine into falt'°. 

^ The fak found adhering to rhe bottom of the pans 
at the Droitwich fait works, and there called clod fait, 
was probably fait thus burnt by haliy fires j and was 
found unfit for preferving beef. 

9 See a reprcfenration of thefe pans with their furnaces 
and the hot houfes behind them, Plate VI. Fig. i. 

*° See Dr. William Jackfon's account of the method 


Whit e S al t. 71 

But the fait made in this hafty manner was 
extreamly weak, and of a fmall loofe grain, 
and quickly grew moift, though dried in hot 
houfes, and was therefore only made for 
prcfent fale''. I am well informed, that 
afterwards they made their fait pans gra- 
dually larger, until they held ahout eight 
hundred gallons j which is the common fize 
of the pans now ufed in Chefliire: And in 
thefe pans, within the memory of feveral 
now living, they finiOied their procefs in 
twelve hours ; and every week reduced 
twelve pans full of brine into fait. They 
found that the fait thus made was greatly 
preferable to that which they had m.ade be- 
fore with more hafty lires, but was ftill too 
weak for curing provifions for fca fervice. 
Of late years therefore they have proceded 
in a more leifurely way, and only work out 
fix pans of brine in the week, emptying 
their pan only once in twenty four hours. 
And fince they fell into this method, their 
fait is much ftronger, and more durable 
in the air than heretofore j being cfleem- 

of making fair at Nantwich in Cheflilre, Ph. Tr. abb, 
by Lowthorp, vol. ii. p. 354, 355. 

" See Dr. Thomas Raftel's charader of this fal^ 
Ph. Tr. abb. vol. ii. p. 358, 359. 

^ ed 

7^ ^e art of preparing 

ed equal in goodnefs to moft kinds of white 
fait now made ; and the demand for it is 
very greatly increafed. In making a kind 
of fait called Ihivery fait, they ufe yet more 
gentle fires, and the procefs continues a long- 
er time than ordinary, as will be hereafter 
more fully explained. And the fait, thus 
made, is of a larger and firmer grain, and 
is alfo ftronger than any other kind of fait 
prepared by them. 


Memoirs for an Analyfn of fca water ^ 

FROM the foregoing procefs it appears 
that fea water, befides common fait, 
contains feveral other ingredients ; fome of 
which in this procefs, are feparated before 
the common fait falls ; and others remain in 
the bittern, after all the fait is extrad:ed. 

I. Of the firfl kind are the fand, mud, and 
other impurities, which by the violent motion 
of the waves are flirred up and mixed with 
fea water, and again fubfide in it, while it 
refls in the ciftern ; or elfe are entangled in 
the whites of eggs and other mixtures, with 
which it is clarified, 

II, Be^^ 

White Salt. 75 

II. Resides thofe grofs fubftances, fea 
water (Contains a glutinous matter of a much 
£ner texture, which is intimately difTolved 
therein. This glutinous matter, in the fore- 
going procefs, is probably feparated from 
fea water by clarification. If we may give 
credit to Count Marfilli, it is of fo light and 
fubtile a nature, as to arife with fea water when 
deftilled in a fand heat ' ; and if fo, may be 
mixed in rain water, and may greatly pro- 
mote the growth and nourifhment of plants ^ ; 
to which ufe (as Pr. Woodward and others 
have obferved) a green llimy fubflance that 
fettles in rain water is in a peculiar manner 
adapted. This vifcous matter of fea water 
feems earthy, faline, and oleagenous. It is 
this in ftormy weather, when the waves rage 
and roar that form.s a thick froth on the fur- 
face of the fea. To this vifcous part is 
chiefly owing the putrefaction of fea water 
when fuffered to flagnate 3 • by which pu- 

* See his Hijioire phyjique de la mer, Partie ii. p. 7.6. 

* The antients theretbre might have fome reafon for 
feigning that Venus fprang from the foam of the fea. Of 
whom Lucretius fings, 

Qu3C, quoniam rerum naturam fola gubernas, 
Nee fine te quicquam dias in luminis oras 
Exoritur, neque fit laetum, neque amabile quicquam. 

5 Of the pucrefadion of fea water when kept 


74 ^he art of preparing 

trefadion this flimy matter is fo attenuated, 
that its texture is deftroyed and part of it 
flies oiF in fetid exhalations, which are pro- 
bably inflammable and permanently elaftic ; 
for it hath been obferved, that the water of 
the Thames and other rivers generate an in- 
flammable air during their putrefaction in 
long voyages. The more grofs and earthy 

in vefTelSj fee the reverend Dr. Hales's Phil, ex- 

And chat the whole mafs of Tea water is fubje(fl to cor- 
rupt, when fuftered to llagnate, Mr. Boyle hath given us 
the following inftances, " A navigator of my acquain- 
tance, having often failed in the Indian and African feas, 
told me that being once, though it was in rhe month of 
March becalmed in a place for twelve or fourteen days, 
the fea, for wane of motion, and by reafon of the heat 
began to ftink ^ fo that he thinks if the calm had con- 
tinued much longer, ihe ftench would have poifoncd 
him. They were treed from it, as foon as the wind be- 
gan to agitate the vvater, which a!fo drove away flioals 
of the fea tortoiles and a fort of fifli that before lay baf- 
king on the top of the v/ater/' 

And Sir John Hawkins takes notice ^ that " were it 
" not for the moving of the fea by the force ot winds, 
" tides, and currencs, it would corrupt all the world. The 
'• experience I fjw, fays he, in the year 1590, lying wi(ha 
*' fleet about the iflands of Azores, almolt fix months, the 
*' greateft part of the time we were becalmed^ with 
" which all ihe fea became fo replenidied with feveral 
*' forrs of geliics, and forms of ferpents, adders, and fnakes, 
" as fe'emed wonderful j fome green, f.) me black, fome 
" yellov/, fome white, fome of divers colours, and 
" many of them had life j and fome there were a yard 
'' and an half, and two yards long, which had not I 


W H I T E S A L T. 75 

parts of this vifcuous matter, after its tex- 
ture hath been thus broken by the putrid 
fermentation, fubfide in the fea water (and 
as the reverend Dr. Hales hath obferved) 
fall to the bottom of the vefTel in a dirty fe- 

III. Besides this vifcous matter, fea wa- 
ter probably holds an earthy fubftance fo 
very light and fubtile that in the foregoing 
procefs it is elevated along with the watery 
vapours j as there feems reafon to conjecture 
from a white fubtile earth, which I have 
obferved adhering to the walls of feveral boil- 
ing-houfes. And although it may feem ab- 
furd to talk of a volatile earth ; yet certain 
it is, that feveral fubftances known to che- 
mifts by the name of faline earths, are raifed 
from certain bodies by their effervefcent mo- 
tions, or by the force of fire. Such are thofe 
volatile fumes that arife from quick lime 
when water is poured upon it 3 and fuch is 

" feen, I could hardly have bclived. And hereof arc 
" wirnefles all the company of the fhips, which were 
" then prefentj fo that hardly a man could draw a 
" bucket of water clear of fome corruption. In which 
" voyage tov/ards the end thereof many of every fhipfeli 
*' fick of this difeafe, and began to die apace ^ but that 
" the fpeedy pafTage into our country was a remedy for 
** the crazed, and a prefervarive for thofe that were not 
l[ touched," See Boyle on the Saltnefs of the fea, 


76 1'he art of preparing 

the fubtile alcaline earthof lime water, which 
arifes with it in deftillation *. 

But we are more certain of the prefence 
of another kind of earth in fea water, which 
in the foregoing procefs is obtained from it 
in very confiderable quantities. This earth, 
to which the fait boilers have given the name 
of fcratch 5, feparates from the brine before 
the fait begins to form in it ; and is either 
taken out in the fcratch pans in the form of 
a white powder, or elfe adheres to the bot- 
tom, and fides of the fait pan in a hard 
ftoney incruftation. This earth may alfo 
be probably feparated from fea water by con- 
gelation. At leaft, I have found that Briftol 
water, frozen into ice and afterwards thawed, 
depolits a white calcarious fediment, very 

•* I was informed by a gentleman of great judgment 
and veracity, who fuperintends feveral large colaieries, 
that when he boiled water which fprang out of a bed 
of free ftone in the boiler of a fire engine, the cylinder, 
into which the watery vapours arofe, was often fo filled 
with a ftony powder, that thepifton of the engine could 
not move in ir, until the powder was cleanfed out j for 
which reafon he was obliged to fupply the engine with 
other water. 

s By Dr. Collins in his difcourfe on fait and Fifheries, 
it is called ftone powder: By Dr. Lifter de font. Med. 
Anglia Arena alba, and lapis albus : By Dr. Fred. Hoff- 
man, Pulvis Candidas. And by the fame, moft aptly, 
Succus maris, Salino-terreus, calciformis. 

2 much 

WhiteSalt. ^^ 

much refembling the fcratch of fea water. 
The petrifying water of Knarefborough being 
in like manner froze, doth alfo part with 
its ftony matter. Thefe earthy particles 
are not feparatcd from fea water in the fame 
ilate in which they were diffolved therein ; 
for when by codlion a large quantity of the 
water is evaporated and thereby thefe parti- 
cles are brought into clofer contad:, they 
ftrongly attract each other, and remain no 
longer fufpended in the water ; but firmly 
concrete into large clufters ; which cannot 
again be diffolved in water ^, unlefs they be 
£ril difunited by art, and reduced into fuch 
minute particles as they exifted in before their 

That thefe particles are extremely fmall 
and minute while diffolved in water, appears 
from their pafling with it through thefiltre ^ j 
fo that, during their diffolution, they feem 
fufficiently fine and fubtile to enter the 
veffels of animals and vegetables. And in- 

^ Hence appears the reafon, why, if the dry remainder 
cxtradled from fea water be again added to the water 
deftilled from it, it is not of the fame fpecific gravity- 
it was of before deftillation • each pound of it, according 
to count MarfiUi, wanting a fcruple of its former weight. 

7 See Exp. made by Dr. Plot, Nat. H'lji. of Stafford- 
Jinre^ Chap. ii. § 109, no. 


^8 'T'hs ar-f of preparing 

deed this fubtile earth appears to be a very 
neceffary ingredient in fea water, ferving for 
the nourifliment of marine plants, and alfo 
of many fifh, more particularly of the tefta- 
ceous and cruftaceous kinds ; to whofe co- 
verings, as well as to corals and feveral other 
iloney plants, it hath a great affinity. 

By a fubtile earth of this kind may be 
produced feveral ftony incruftations, and 
petrefa6tions of mofs, wood, and other ve- 
getable fubflances ; alfo ftaladites, and 
other ftony concretions^. 

This earth is capable of being difTolved 
by water in very confiderable quantities. The 
water of the fait fprings of Weflon in Staf- 
fordfliire contains about a thirty fixth part 
of its whole weight of this earth j which is 
nearly in the fame proportion, in which com- 
mon fait is ufually found diffolved in fea 
water 9. 

The great folubility of this earth in water, 
fliews that it nearly approaches to the na- 
ture of falts. It is even found to enter the 

' See an inftance of this kind in the following chapter 
from Dr.Scheuchezr's Account of the Saltivorksat Bevieux 
in Switzerland. 

9 See Dr. Plot's Nut. Hi/i. of Staffordjhire, C. ii. 


White Salt. 79 

compofition of perfedt falts. For being long 
expofed to the open air, it imbibes the aereal 
vitrioHc acid, and with it is converted into a 
neutral fait, which Dr. Lifter ranks amongft 
the fpecies of his calcarious nitre '°. This 
fait, in tafte, very nearly refembles the bit- 
ter purging fait of Epfom waters j as I ex- 
perienced in fome of it which I found ger- 
minated on ftone fcratch, that had been kept 
by me four or iive years. 

From the foregoing obfervations, this 
earth appears to have an alcaline quality ; 
which is further confirmed by other experi- 
ments. For when reduced to powder, and 
mixed with fyrup of violets diluted with 
water, it inftantly turns the mixture from 
a blue to a green colour. I have known the 
glafs makers fubftitute it for kelp in their 
compofition for making glafs. And it is 
well known that kelp, or the aflies of the 
herb kali, owes its quality of vitrifying with 
fand, chiefly to the alcaline fait which it 
contains. This earth, being mixed with 
clay, makes a ftrong cement, which the fait 
boilers ufe for repairing their furnaces. 

" In his treatife D( fontlh. medicat. JytgUiff^ L. i. 
P 3^- 



So ^he art of preparing 

It is well known that the fhells of the 
fea fifh (which feem to be nourifhed chiefly 
by this fubtile earth) partake of an alcaline 
nature, and may by calcination be reduced 
into quicklime ; to which, we may con- 
jedure from the preceeding experiments, 
that this earth bears fome affinity. And 
having purpofely made the trial, I found 
that ftone-fcratch after calcination by a vio- 
lent heat in an air furnace, fell into powder 
in the open air, and had other properties of 
quick Hme. 

The marine fcratch therefore feems to 
defervethetitleof a faline calcarious earth. But 
I am far from thinking that all earths which 
come under that general denomination, are 
exadlly of the fame nature, and agree in all 
their properties. On the conrary it is more 
reafonable to believe that there are feveral 
kinds of calcarious earth, which are more or 
lefs fubtile, more or lefs corrofive, and have 
other fpecific diflferences j one kind bearing a 
refemblance to chalk, another to limeflone, a 
third to quick lime, and a fourth to ala- 
bafter ; one kind, with the vitriolic acid 
compofing alum, another with the fame acid 
Epfom-faltj and others with the fame acid 


White Sal t. 8t 

other kinds of calcaneus falts. So that thefe 
earths ought not to be all confounded toge- 
ther, but each kind diftinguifhed by its pri^ 
vate properties. 

The magnefia alba, fo juflly celebrated 
in Germany for its mild purgative anti-acid 
virtues, is a kind of calcarious earth, very 
neary related to the fcratch of fea water 5 
being with acids converted into a bitter pur- 
ging fait, which is not the cafe with quick- 
lime, crabs eyes, and feveral other alcaline 
earths. Whether the marine fcratch will 
have the fame effedls with the magnefia upon 
the human body, muft be determined by fu- 
ture trials. It is certain that feveral mineral 
waters owe their purging qualities not to any 
perfecfl fait with which they are impregnated ; 
but to a fubtile calcarious earth, as Dr. Fred. 
Hoffman hath fully proved in the waters of 
the Caroline baths in Germany* 

In the examination of mineral waters ; 
their earthy ingredients, which are too often 
confidered as inert, and without efficacy, do 
therefore require a nicer attention. We find 
that calcined fpunge, which is a marine pro- 
dudiion and holds a calcarious earth, is a ufe- 
ful remedy in fcrophulous diforders -, and the 
falutary effects, which feveral mineral waters, 

G and 

82 T^he art of preparing 

and which fea water hath alfo been obferved 
to produce in thofediftempers, may be attri- 
buted, in part at leall, to the calcarious earth 
which they contain. There are many pur- 
ging waters, as thofe of Epfom and Scarbo- 
rough, which agree with fea water in that they 
hold a calcarious earth, together with a mu- 
riatic and a c::ilcarious fait. But how far the 
earths of thefe waters agree with the marine 
fcratch, and in what they differ from it, and 
from each other, can only be determined by 
proper experiments. 

IV. The ingredient of fea water, which, 
in the foregoing procefs, falls next under 
our confideration, is common fait. And 
the quantity of this fait contained in fea 
water, is found very different in different 
parts of the ocean, and even in the fame 
parts at different times. 

The Baltic fea, receiving more frefli wa- 
ter than exhales from it, is but weakly im- 
pregnated with fait. The water of the Bri- 
tifh and German feas, is confiderably falter 
than that of the Baltic -, and the water of the 
Mediterranean (from which more frefh wa- 
ter is thought to exhale than falls into it) 
is efteemed falter than that of the Britifli or 
German feas j and the water of other feas 
may probably contain a larger proportion of 
z fait 

White Salt/ S3 

lalt than that of the Mediterranean, as hath 
been conjectured of the water on the coaft of 

A phyfician, to whom Mr. Boyle recom- 
mended the trial, affirmed, that in failing 
from England to the Weft Indies, he found 
the water of the ocean to increafe in gravity, 
the nearer he came to the line, till he arrived 
at a certain degree of latitude (as he thought) 
about the thirtieth 3 after which, it feemed 
to retain the fame fpecific gravity 'till he 
came to Barbadoes or Jamaica ^^. But the 
authority of this gentleman does not feem of 
fuch weight as that of father Feuillee, who, 
in paffing through the ftreights of Gibraltar 
towards America, obferved the water to dimi- 
nifh in weight in proportion as he approached 
the line '3. 

This difference in the faltnefs of the Jfea 
in different places, feems to proceed from 
various caufes. As, from the quantity of va- 
pours exhaling from it, which is very diffe- 
rent in different places. Alfo from the 
quantity of frefh water received into certain 

" See Boyle on the Saltnefs of the fea, abb. by Dr. 

♦ Shaw, vol. iii. p. 224. 

'* See the fame work, p. 223, 
\' See Memoires of the Royal Acad, for the year lyiii 
G 2 parts 

^4 ^h^ ^^^ tf preparing 

parts of it, in rains, or from the mouths of 
rivers '+. Or from beds of foffil fait, which 
may be feated in feveral places at the bottom 
of the ocean '^ Or from the fait waters of 
fprings and rivers which are difcharged into 
it, in certain places'^. 

'+ Count MarfillL found the water of the Archipelago 
taken up nigh Smyrna conlidcrably heavier than that 
of the Euxine ^ and that of the channel of Conftantino- 
ple,or the Thracian Bofphorus, in fome places heavier, 
in others lighter than that of the Euxine according as it 
was taken up nearer to, or farther from the mouths of 
rivers. See his Obfervatlons made on the Bofphorus of 

Such vaft quantities of water are difcharged from the 
Riv della Plata in Brazil, that frefli water may be taken 
up in the ocean fifteen miles from the mouth of that 
river. The fame is reported of the river Qiiire in 

On the coaft of Malabar, during the rainy feafon, fo 
much water falls in rains, and is difcharged from rivers, 
that the Tea water in feveral parts nigh land becomes al- 
moft fweet and potable. Du Hamel Phil. Burgund. 
Cap. De maris Jalfcdine. 

's As nigh the ifle of Ormus. And in deep parrs of 
the ocean, where the water is not difturbed, the fait 
may diffolve very (lowly, as all the water adjoining to 
the fait rocks will be fully fatiated with it. 

"^ Moft of the rivers in the kingdoms of Algiers and 
Tunis are impregnated with fait j and doubtlefs contri- 
bute to the extraordinary faltnels of the Mediterraneaa 
waters. Herrera informs us, that the Rio de la fal in 
Chili is fo extremely fait, that the parts of horfes wee 
with it, as foon as they arc dry, appear incrufted over 


Wh I TE S A LT. 85 

The reverend Dr. Hales, by a gentle eva- 
poration of fea water taken up near the Buoy 
at the Nore at the mouth of the Thames ob- 
tained from it -'^ 2 of its v^hole weight of 
fait. And from the Mediterranean water 
taken up thirty leagues north of the iile 
of Malta ^'_3 of fait '7. Count MarfiUi 
found that water taken from the furface of 
the fea in the gulf of Lyons, yielded by at 
gentle diftillation only ^V of ifs whole weight 
of fait; whilft that which was taken up at 
the fame time and place from a great depth 
yielded ^'- of fait ; and hence concludes that 
fea water is much falter in profound parts of 
the ocean, than at the furface ^^. This in- 
deed may be the cafe in the gulf of Lyons 
nigh the mouths of the Rhone ; and alfo 
nigh the mouths of other great rivers, whence 
the frefli water flowing out, is mixed chief- 
ly with the fuperiicial fea water, v/hilfb that 
in deep parts remains undifturbed. But this 
rule does not hold univerfaliy true in all 
places ; for Mr. Boyle found the water of 
the Britiih channel equally heavy at the fur- 

with fair ; and that the fait lies concreted on i]\c borders 
of the river, 

'-' See his Pb. Experiments on di/lilkd ftd 'water. 

!« See his Hijicire Phyf. de la Mer, 

G 3 face 

S6 ^he art of preparing 

face and at the bottom. And atfome places 
(as in the Pacific ocean) where large quan- 
tities of water arife in vapours, and very little 
falls again in rains, or is received from rivers, 
the fuperficial water may probably be much 
falter than that which remains undifturbed 
at the bottom. 

It ought to be remarked, that in the fore- 
going experiments of extracting the fait from 
a certain quantity of fea water, all the dry 
remainder hath ufually been taken for com- 
mon fait J although it is not a pure marine 
fait, but hath feveral other ingredients mixed 
with it, particularly a confiderable portion 
of a calcarious earth, and alfo the falts of the 
bittern. It like wife ever contains a confide- 
rable portion of aqueous moifture, which is 
more or lefs according as the heat was con- 
tinued a longer or a jfhorter time after the im- 
pure fait or remainder appeared in a drj^form, 
Mr. Boyle having evaporated water taken 
up in the Britifh channel to a drynefs, found 
the dry remainder, which he calls fait, to 
weigh near j~ of the wl.ole water j but after 
heating and drying it well in a crucible, it 
only weighed ~j of the water ufed '^. The 

^? See his Treatife on the faltnefs of the fea. 


Wh I TE S A LT. 87 

quantity of dry remainder will alfo be con- 
fiderably lefs when the water is evaporated 
from it with a violent heat, than Vv^hen only 
a gentle heat is applied. So that from thefe 
experiments, in which a certain quantity of 
fea water is evaporated, and the impure fiilt 
remaining weighed j nothing certain can be 
determined of the true quantity of common 
fait vi^hich fea water doth contain. 

As true an ellimate may probably be 
made from the experiments of the fait boilers. 
Thofe of them who have been moft accurate 
in their trials affirm that in Solway Firth on 
the coafts of Cumberland, they commonly 
obtain a pound of pure marine fait from forty 
pounds of fea water ; and after the greatefl 
draughts, feldom more than a pound of fait 
from thirty five pounds of water j but, after 
heavy rains and great land-floods, the fea 
water is there fo weakened, that it does not 
afford above a fiftieth part of its weight of 
pure fait. The Newcaftle fait boilers afi"ert, 
that, on the coafls of Northumberland and 
Durham, from thirty tuns of fea v/ater, they 
ufually extradl a tun of fait j but in this cal- 
culation it is probable that they do not e/li- 
mate the quantity of water by v/eight, but 
by meafure. 


88 I'he art of preparing 

From all thefe obfervations, it may be 
concluded in general that fea water taken up 
on the Britifh coafts, at fome diftance from 
the mouths of rivers, feldom holds more 
than yV, or lefs than -V of common fait. 
And that the water of fome feas, as of the 
Baltic is impregnated with lefs fait, and that 
of the other feas with more fait, than the 
water taken up on the coafls of Great 

Besides common fait, fea water contains 
feveral other falts which are found in the bit- 
tern that remains in the pan after all the ma- 
rine fait is extracted. 

V. For firft it contains a bitter purging 
fait, known better to many by the name of 
Epfom fait J having firfl been extrad:ed for 
medical ufes from the waters of Epfom, 
and afterwards from thofe of Dulwich, 
Shooters-hill in Kent, and from other pur- 
ging waters in feveral parts of England. 
But all this fait now vended, is prepared in- 
tirely from the marine bittern, at the fait 
works nigh Newcastle, and at thofe at Le- 
mington and other parts of Hampfhire. To 
this fait feems chiefly owing the bitter tafte 
of fea water, although the opinion hath ge- 
nerally prevailed that this tafte proceeded 


White Salt. 89 

from bitumen ^°. From the experiments 
made on this fait, it feems compofed of a 
vitrioHc acid, united to a large quantity of a 

^° I readily grant thit there are feveral bituminous 
bodies, which in various parts are mingled with the ma- 
rine waters. Thus Mr. Boyle informs us that the Bar- 
badoes tar is carried in confiderable quantities trom rocks 
into the fca. And count Marfilli obferved Ipiral fila- 
ments to arife in the Tea Marmora nigh Confiancinople, 
which concreted into bitumen exadly of the fame 
kind v/ith that which he had obferved to flow from a 
bituminous fountain in the ifle of Zanr. On forne of 
the coafts of Italy they fkim an oil like petroHum from 
the furface of the fea. And ambergreece may proba- 
bly be a bituminous fubftance caft up from the ocean. 
Many parts of the fea are alfo frequently covered with a 
fubtile pinguous fubftance, which fhines and gives light in 
the night. Thefe undluous fubftances may impart vari- 
ous properties to fea water in places where they abound j 
but none of them are found conftantly mixed with the 
marine water ^ nor does it appear that they are capable of 
giving it its bitter tafte j fo that this tafte feems to proceed 
almoft entirely from the bitter purging fait, every where 
prefent in fea water. Count Marfilli hath indeed proved 
that a fpirit diftilled from pit coal will give water a bitter 
tafte, but he hath not proved that feawater is impregnated 
with fuch a fpirit ; on the contrary diftilled fea water hath 
no bitter tafbc, as Dr. Hales hath well remarked, and There- 
fore the marine waters are not impregnated wijh fuch a 
volatile fpirit, but owe their bitternefs to a fixed principle. 
And that pit coal can fcarce impregnate water with fuch a 
fixed principle, appears from examining the water which 
flows from large ftrata of this mineral ,• which water is 
commonly impregnated with iron, but hath never been 
obferyed to have a bitter tafte. 


go *ithe art of preparing 

ealcarious earth ; and may therefore be cal- 
led a vitriolic ealcarious fait *'. 

VI. Another fait is found in bittern, 
ivhich may be called a muriatic ealcarious 
fait ; its acid principle being fpirit of fait, 
which is loaded with a large quantity of an 
earthy fubftance moft nearly related to quick- 
lime. For this fait, being expofed to the 
iire, doth not part with its acid fpirit until 
its faline earth is reduced to a calx more 
fliarp and corrofive than quicklime itfelf. 
This fait remains in the bittern after the bit- 
ter purging fait is extracted from it ; and, 
though a neutral fait, can fcarce be brought 
into cryftals, but by the force of fire may be 
reduced to a folid form ; which yet it re- 
tains with difficulty ) for of all the coagulable 
falts, it moft greedily imbibes the aerial hu- 
midity, and with it moft readily runs per de- 
liquium-"*, This fait, though little known, 

" Of this and the following falc fee an account pub- 
liflied in the Tranf. of the Royal Society N" 377, 378. 
by Mr. Brown the Chemift. 

Aifo Dr. Hoffman's Obf. Phyf, Chem, De Lixtv'io a 
Jale reli^o. 

** The great relucflancy which this fak difcovcrs to 
be reduced to a folid form, (cems alfo to fhew the near 
affinity between iis earth and quicklime. For Sthal in- 
forms us J that thofe who purrify nitre find no better me- 


White Salt. ^i 

is now applied to fome profitable ufes -^^ and 
might be applied to other ufes medical as 
well as oeconomical j which are left to the 
difcovery of the ingenious. 

VII. Besides thefe calcarious falts, the 
marine bittern contains a confiderable por- 
tion of a fixed mineral alcali, as may be 
judged from its turning fyrup of violets of a 
green colour. Whether this fait exifts in 
fea water before its coition, feems difficult 
to determine, as will more fully appear from 
fome experiments hereafter to be related. It 
is however certain, that fea water partakes 
of an alcaline quality ; for though the co- 
lour of fyrup of violets is not readily changed 
by it, yet the blue tin(5ture of flowers of 
Cyanus (which more quickly turns red with 
acids and green with alcalies than iyrup of 
violets) being mixed with fea water, the 
mixture in about twelve hours becomes of 
a pale green, as I have frequently experienced. 

thod of freeing it from marine falc than by mixing it with 
lime water ,• which uniting to the acid of fea fair, there- 
with forms a fahne Hquor, which will not flioot into 

*J Amongftthofe ufes, I do not reckon one to which 
fome have applied it ; counterfeiting therewith the blood 
of the Popiili faint JanuariuSj which, as many believe, 
liquefies at the approach of the head of that f^int. 


92 The art of preparing 

But whether this change of colour proceeds 
from the calcarious earth or from a fmall 
portion of an alcaline fait contained in fea 
water, mufi: be determined by future expe- 
riments. It however feems ftrange that fo 
alcahne a fubflanceas fcratch, which, when 
reduced to powder, fo readily turns thefe 
mixtures green, fhould yet have fo little 
efFedt upon them when more intimately dif- 
folved in fea water. 

The ingredients of fea water already 
mentioned are the chief which fall under 
the cognifance of the marine falt-boiler. 
Although it is alfo impregated with the 
feeds, fperm, and excrements of innumerable 
kinds of plants and animals, and the tinc- 
tures which thofe plants and animals impart 
to it, while they corrupt and dilTolve there- 
in. Thefe, together with diverfe faline and 
fulphureous bodies not here mentioned, will 
neceflarily fall under the confideration of 
thofe, who fhall hereafter attempt to oblige 
the world with a natural hiflory of the ma- 
rine waters ^'^. To whom, as well as to the 

*-* It may indeed Teem ftrange, that, after the learned 
have rpenc fo much rime and fVudy in fearching in- 
to the nature of mineral waters, the water of the 
ocean, that grand fountain of fountains, which nou- 


Whit e S a lt. 95 

inquifitive falt-boiler, the imperfed me- 
moirs here given may not be wholly un- 


T'he method of boiling brine fait. 

OF fait boiled from the waters of wells 
and fprings, which we call brine fait, 
great quantities are daily made and ufed ; 
efpecially in countries remote from the fea, 
as in the inland parts of Germany, in Hun- 
gary, and Switzerland, in which and in ma- 
ny other countries, fprings of fait water are 
very common '. 

riflies and fupports fuch an infinlre variety of creatures ^ 
which hath iuch remarkable etfefts upon the human 
body, which difFufes its influence over the whole fub- 
lunary creation, and is fo wonderfully adapted to the 
various ends of the all-wife creator j fliould neverthelels 
remain almoft totally neglecffed by them. 

* Amongft the moft remarkable fait fprings, may be 
ranked thofe of Salins in Franche Comptc; arc Teem- 
ing to vie with nature, in contributing to render them 
moft furprizing, Thele fprings are lituated in deep 
caves, which in the greater work (for there are two in 
that City) are about four hundred feet in length, and fifty 
or fixty in breadth. Into thefe caves (of the greater 
work) they defcend by a ftone ftair-cafe of forty one 
fteps, and then by wood-ftairs of twenty fteps. At the 
bottom of thefe ftairs, is a cave with an arched roof. 


94 ^he art of preparing 

In feveral parts of England, as in Somer- 
fetihire, Cumberland, Weftmoreland, Dur- 

This ftift cave or vault is forty feet long, and thirty 
two and an half broad ; and in it are fix fprings of 
fait water, and two of frefh water, all which gufli out 
of the fame rock, within the fpace of fourteen it.ti. 
From this cave or vault they go into others, fupported 
in the middle by a row of thick pillars, on which 
double arches reft. They then pafs through two gates 
into a fpacious vault thirty five feet high, and fupport- 
ed nigh the enterance by four ftrong pillars placed 
fquare way?, and in the middle fpace within thefe pil- 
lars is a large bafon, into which the waters of the feveral 
fait fprings are colle<fted. In the fame vault beyond thefe 
pillars are four others, placed in a row fupporting dif- 
ferent arches of fixcy feet in length, and forty eight 
feet in breadth j beyond which there is an irregular 
fpace fixty three teet long, in which are fix or feven 
fprings of fait water, and ten or twelve of frefli. 

The fait waters of thefe fprings, and of the fix fprings 
before mentioned, are kept feparate from the frefli 
water; and arc all conveyed through gutters into the 
large bafon before mentioned. From this bafon they 
are drawn out, by an engine called the wheel and 
buckets, into four large ftone bafons or refervoirs, one 
of which holds fifteen thoufand hogfheads, and the other 
three together twenty five thoufand hogfheads. From 
thefe refervoirs they are drawn off, as occafion requires, 
into fmaller cifterns placed nigh the boiling houfes (the 
waters contained in the feveral bafons, (as they are drawn 
from the fprings at different times, and are of unequal 
ftrength) are mixed together in fuch proportions in the 
cifterns, that each pound yields about three ounces of 
fait. The water of the frefh fprings is alfo colledtcd 
together in the caves, into a bafon prepared to receive 
it, and is raifed by means of a crane to the level of a little 



Whit e Salt. g^ 

ham, and Yorkfhire, many fait fprings have 
been difcovered ; but tliey are either weak, 
or fituated where fuel is fcarcej and for 
thefe and other reafons, are not wrought for 

But in other parts of England there are 
many rich and valuable falt-fprings, from 
which great ftore of fait is daily extraded. 
Of thefe fome are fituated in Stafford- 
fliire, and feveral in Lancafliire; but the 
chief are thofe at Droitwich in Worcefter- 
ihire, and Northwich in Chefhire, about 
which laft mentioned place, there are many 
rich mines of foffil fait; above and beneath 
the beds of which, the brine is commonly 
found. And when, as it frequently hap- 

brook, into which it runs through a fubterraneous 
conduit. For a farther account ot thefe fprings and 
and faltworks, See the General Syjiem of Geography lately 
publifhed at London vol. i. p. 34(J. 

The fait fprings in England and other countries are, 
moft of them, wells or pics of different depths, in 
fome of which the brine ftagnates, and never rifes to 
the top, but flows out at the top of other wells, 
when it is not drawn out for ufe. See a Defcription 
of the fait fprings at Hall in Saxony in Hoffman's 
Treatife Des Salinis Hallens : Alfo of feveral in Eng- 
gland in the Ph. Tr. Ab. vol, ii. 

Ac fome plcaes, as at Schower in upper Hungary, 
the water which they draw from their fait mines, be- 
ing a very ftrong brine, they boil into falto 


g6 *the art of preparhig 

pens, the fait is in a good meafure exhauft- 
ed, and the brine is fo weak, that it can no 
longer be wrought to profit 3 they then fink 
pits in other Hkely places, and feldom fail 
of meeting with flrong brine. There are 
alfo many brine fprings in other parts of the 
la/l mentioned county, as at Middle wich 
and Nantwich ', at the laft of which places 
the pits are of a very ancient ilanding, and 
are laid to have been wrought in the time of 
the Roman government. 

The brine of thefe fprings is obferved 
to differ greatly in ftrengtli and purity; 
fome kind of brine affording a much larger 
quantity of fait, and fitter for moll ufes, 
than that which is extracted from other 

That brine may be efteemed the fiirong- 
eft of which a pound averdupoize yields fix 
ounces of pure fait. The brine of Barton 
in Lancafhire, and of feveral pits at North- 
wich is nearly of this flrength, being almofl 
fully faturated with fait. That of Droit- 

* Moft of which are fituared nigh the river Weewer. 
" Sink on either fide the faid river for raany miles, 
" and you will fcarce mifs of brine." Lijler's Ohf. on 
the midland fait fprings. Ph. Tr. Abb, by Lowthorp. 
vol. p. 351. 


WhiteSalt. «yj 

wlch, Upwich and Middlewich contains 
about a quarter of fait. The brine of other 
fprings at Northwich and Nantwich yields 
about a lixth, and that of Weflon in Staf- 
fordfhire only about a ninth part of fait : In 
England they feldom boil a weaker brine 
alone, than that lafl: mentioned; but in 
fome parts of Germany, where fait is very 
fcarce, they extradl it from water which is 
more weakly impregnated with it, than the 
marine waters. 

It hath been obferved at fevcralfalt fprings, 
that the brine is much flrongcr at the bottom 
of the pits than nigh the furface ; alfo in dry 
weather than in wet ; and when the pits are 
conflantly drawn, than when little brine is 
drawn out of them. But in fome fprings, 
as in thofe of Salins in Franche-Comte, the 
brine is not only found more plentiful, but 
alfo flronger after wet, than after dry wea- 

Besides common fait, the brine of moft 
fprings is impregnated with many other in- 
gredients, with the nature and properties of 
which the brine falt-boiler ought to be ac- 
quainted, as by that means he will be enabled 
to exercife his art with greater dexterity and 

H And 

'98 ^he art of preparing 

And firft, the brine of moft fait wells, 
and particularly the Englifh brine, hath 
fomething of a fulphureous principle mixed 
with it, as may be concluded from its fetid 
fulphureous fmell, which quickly goes off 
with boilings This fulphureous principle 
gives to the brine impregnated with it, an in- 
teftine putrifying motion j and makes it quick- 
ly corrupt the flefli of animals fleeped therein. 

2. The brine of many of the Englifh fait 
fprings turns atramentous with galls ^, and 
hath mixed with it an ochery fubftance, 

J " The brine of the Droicwich pits (as Dr. Lifter 
" aflures us) ftinks like rotten eggs, and will, if flefli be 
*' pickled wiih ir, make it ftink in twelve hours. And 
*' yet (adds he) the fait that is boiled of thcfe pics is ac- 
" counted the very beft inland laltof all England, and, 
*' I believe, as good as any in the world." Ph. TranJ. 
cbr. by Lowchorp, vol. ii. p. ^62. 

It hath fince been found that the Droitwich brine, after 
it is boiled and clarihed, is an excellent pickle for curing 
beef, and other domeftic ufes. 

In the level or gallery, through which the fait water 
is conveyed to the falterns at Bevieux in the Pais de Vaux, 
Dr. Scheuchzer obferved feveral veins of virgin fulphur. 
Several of the miners, in digging the faid level, were 
killed by explofions of the fulminating damp. 

+ This Dr. Lifter obferves of the brines of Nant- 
wich, Middlewich, Northwich, Wefton, and Droit- 

Dr. Leigh, in his Nat, Hijl. of LancaJJnre and Che/hire^ 
affirms, that there are feveral fait fprings in thofe counties, 
the brine of which is not altered by galls. 
^ • - ' which 

Wh ite S al t. 99 

which feparates from it, and fubfides, when 
the brine is fufFered to ftand In an open 
veiTel j or falls to the bottom of the fait pan 
as foon as the brine begins to boil. 

3. Brine hathalfo commonly mixed with 
it a large quantity of a light calcarious earth, 
or fcratch, exactly refembling that of fea 
water. It abounds in the Chefliire brine, and 
in all their falterns they coiled: it into fcratch 
pans i and once a week, or oftener, pick off 
the ftoney cruil which adheres to their fait 
pans. It is alfo found in the brine of the 
German fait fprings. And it is probably the 
peculiar excellency of the Droitwich brine to 
be intirely free from any mixture of this earth 5. 

5 Dr. Scheuchzer gives the following relation of the 
manner of depurating the brine from part of this earth aC 
the works at Roche, or Bevieux. " Antequam vero in 
" ipfis cortinas, qua; ferreie funt, admiccitur (aqua {A\iz) 
" depuratur in alveoprxlongoducenrorum forte pedum, 
*' decern circiter lato, tc<fto columnis inliftente^ 
" a pluvise mifcela munito : hie ordine fufpen- 
" duntur fafciculi ftraminum oifto circiter pedum, 
" quibus aqua falfa ex alveo afperfa affigic particulas 
" terreas, quas fenfim ad digici fere crafficiemi incruftanc 
" ftramineos culmos, atque tunc rejiciuntur, ut novis fafci* 
" culis ftraniineis fufpendendis locum cedant. Adno- 
" tari meretur, horum Sraladirarum vel Scriarum arte- 
" faclarum non externa folum cylindrica figura ita f«pe 
" concreta, ut maffa Stelechiten vel Sfala<5liten ramofuni 
*' referat, fed praeprimis ftrudura interna veluti radiata 
*' radiis undique a peripheria ad centrum convergentibus 

H 2 4. Ax 

100 ^he art of preparing 

4. At the bottom of feveral brine pits 
there is found a light black mudj which, 
when ftirred up, infedls the whole fpring, 
like the fcuttle fiili, black. Some of the 
pits in Chefliire, which abound with this 
mud, are in boggy grounds, where the foil 
is a peat earth. The briners there frequently 
empty thefe pits, in order to cleanfe them 
from this mud. At Hall in Saxony, they 
fix bundles of rods in the middle of their 
pits ', through which the brine pailing, this 
mud is intercepted, as by a flrainer. 

5. The brine of moft fprings is alfo im- 
bued with various kinds of falts. In boil- 
ing the waters of the German fait fprings 
there remains a ponderous liquor, which they 
call Mutter foole^ or mother brine, refembling 
the marine bittern, but feeming to partake 
more of the muriatic calcarlous, than bitter 
fait of fea water, as may be concluded from the 
experiments made thereon by Dr. Fred. Hoff- 
man ^. Moft of the mineral waters of Eng- 
land, which are impregnated with bitter fait, 

" infignita, cui genefi anfam dedic sequalis undique 
" partiura terrearum ad ftramen adhajfio^ materia ha- 
" rum Striarum eft coloris terrei fere vel flavefcentis, 
" fubftantix fpecularis, un ipforum Sraladlitarum.*' 
Iter Alpinum fepthnwn. 

6 Obf. Phyf. Chem, Lib. ii. Obf, xviii. 


Whi te Salt. lof 

do with it hold plenty of common lalt. And 
we are afTured by Dr. Leigh, that thofe two 
falts are alfo found together difTolved in the 
brine of Chefhire^. 

6. Hoffman informs us, that feveral of 
the fait fprings in Germany are impregnated 
with a mineral alcali ; and many of the 
Englifh brine fprings feem alfo to partake of 
the fame, as will be more fully difculTed 

The antient methods of boiling brine into 
fait in Chefhire and Worcefterfhire are ac- 
curately defcribed in the adls of the Royal 
Society ; and the method formerly ufed in 
StafFordfhire is related in Dr. Robert Plot's 
Natural hijiory of that county, to which ac- 
counts the reader is referred. The method 
now pra<flifed in thofe counties, agrees pretty 
well with that ufed in Germany ; and as it 
differs in feveral particulars from the method 
of boiling fea fait, before related, it is ne- 
cefTary here to give a fhort account of it. 

The brine being received from the well 

7 *' Befides the marine fait, thefe fprings do likewife 
" contain the nitrum calcarium." Leigh, Nat. Hiji. of 
Lancaj})ire^ Chejhire^ ^c. p, 44,. And in the following 
p3ge and elfewhere he tells us, that by Nitrum Calca- 
rium he means the bitter purging fair. 

H 3 into 

102 ^he art of preparing 

into the ciilern, is from thence drawn, as 
occafion requires, into the fait pan. Thefe 
pans are of the fame form with thofe 
ufed in boiling fea faltj but lefs, ufually 
holding about eight hundred gallons ^ ; and 
in Chefhire are made of iron, but at Droit- 
wich of lead, The fait pan being filled with 
brine, and the fcratch pans placed at its cor- 
ners, the fire is kindled, and fome blood 
from the butchers is difiblved in a little of the 
brine, and mixed with that in the pan, 
in order to clarify it 9. (An ounce of 
blood, it is faid, will clarify eight hundred 
gallons of brine.) The brine, as foon as it 
boils, is fkimmed ; and afterwards fuflTered 
to boil violently, till the fait begins to form 
in it. The fcratch is then all feparated, and 
the fire being flackened, it is fuffered to fub- 
fide , and, when it hath all fallen into the 
fcratch pans, they are then taken out of the 

* At Tnn'thalle in Tirol the iron pans, in which they boil 
their fal:, are forty eight feet long, thirty four feet broad, 
and three feet deep. 

At Salinsthey ufe iron pans of a round form, twenty 
eight feet in diameter, and fifteen inches deep. The 
praiflice of thefe foreigners is highly worthy the imita- 
tion of the jEnglifh, as will be explained in another 

9 At Droitwich, and fome other places, they clarify 
their brine with whites of eggs. 


White Salt. loj 

fait pan. But when they boil brine of fo 
great ftrength as to be almoft fully faturated 
with fait, they cannot conveniently clarify 
it, becaufe the fait begins to granulate before 
the brine boils j in that cafe, therefore, they 
mix no blood with it, but boil it briikly for 
a little time, till all the calcarious earth and 
ocher are feparated ; thefe mix with the fait 
then formed, and render it very impure; 
which is therefore raked out, and thrown 
away as ufelefs. And this they call the 
firft clearing of the pan »°. 

In either cafe, as foon as they have cleared 
the pan of fcratch, and other impurities, and 
have brought the brine to fuch a ftate, that 
the fait begins to cryflallize in it j they then 
ufually mix with it ale, butter, and other 
additions, or feafonings, which they add, 
with a defign either to corre<5t fome fup- 
pofed faults of the brine, or to make the 
fait of a fmaller grain, or for other purpofes, 
of which it will be neceffary to treat here- 

^° When the brine was weak, they formerly filled up 
the pan two or three times with new brine, as in pre- 
paring fea fait ; but now they commonly heighten fuch 
weak brine with rock fait. 

H 4 These 

104 ^f^^ '^^^ of preparing 

These feafonings being well mixed with 
the brine, they boil it very gently during the 
reft of the procefs, and when as much fait 
is formed as will fill two or three of their 
large wicker bafkets, they then rake it to 
the fide of the pan, and fill it out into the 
balkets ' ^ ; placing them over the leach- 
trough, that the leach-brine may drain into 
it from the fait. The fait taken out, they 
call a draught of fait, and the operation a 
clearing of the pan. And in this manner 
they draw the fait, and clear the pan five or 
fix times in each procefs ^ leaving at laft, 
only a few quarts of brine at the bottom of 
the pan, to keep it from burning. The 
whole procefs ufually lafts about twenty four 

" Thefe bafkets, which are alfo called barrows, and 
uiaally conrain about a buftiel of fait, are of a conical 
figure, open at the bafe j fee them rudely reprefented, 
together with the leach-troughs, hot-houies, &c. 
Plate VI. Fig. i. and 2. 

" And here it may be proper to take notice of Mr. 
Lowndes's laudable attempts for improving the Englifli 
brine fair. And as he hath lately been induced by par- 
Jiamentary encouragement to reveal his fecrer, I fhall 
therefore here give his procefsin his own words,- fomeof 
the advantages, as well asdefedls whereof, will be pointed 
cut in the following fheets. 

" Let a Chefhire fait pan (which commonly contains 
f sbout eight hundred gallons) be filled with brine, to 


White Salt. toj 

The (alt, after it hath drained for an hour 
or two in the bafkets over the leach-trough ; 
is removed into the hot houfe, behind their 
furnace, where it remains four or five hours, 
till thoroughly dried and is then taken out of 

*' within about an inch of the top jthen make and light 
*' the fire^ and when the brine is jufl lukewarm, put in 
" about an ounce of blood from the butcher's, or the 
*' whites of two eggs : let the pan boil with all poffible 
" violence. As the Icum rifes, take it off: when the frefli 
*' or watery part is pretty well decreafed, throw into the 
'^ pan the third pare of a pint of new ale, or that quantity 
" of bottoms of malt drink. Upon the brine's beginning 
" to grain, throw into it the quantity of a fmall nutmeg 
" of frefh butter • and when the liquor has faked for about 
" half an hour, that is, has produced a good deal of fair, 
** draw the pan, in other words, take out the lalt. 

" By this time the fire will be greatly abated, and fo 
" will the heat of the liquor. Let no more fewel be thrown 
" on the fire ; but let the brine gently cool, till one can 
" juft bear to put one's hand into it : keep the brine of 
" that heat as near as poffible ; and when it has worked 
" for fome time, and is beginning to grain, throw in the 
*' quantity of a fmall nutmeg of frefh butter, and, about 
*' two minutes after that, fcatter throughout the pan, as 
" equally as may be, an ounce and three quarters of clean 
" common allum, pulverized very fine- and then inftantly, 
" with the common iron fcrape-pan, ftir the brine very 
" brilkly, in every part of the pan for about a minute. 
" Then let the pan fettle and conftantly feed the fire, fo 
" that the brine may never be quite fcalding hot, nor 
*'- near fo cold as lukewarm : let the pan ftand working 
*' thus for about three days and nights, and then draw it. 

*' The brine remaining will by this time be fo cold, 
" that it will not work at all j therefore frefli coals muft 
** be thrown upon the fire, and the brine muft boil 
f* for about half an hour, but not near fo violently as 


io6 ^he art of preparing 

bafkets, and laid up in the ftore houfe for fale ''. 
In all the Englifh brine fait works, the 
liquor called leach brine, which drains from 
the fait in the bafkets, or remains in the 
fait pan after the procefs is finiflied, is not 
thrown away as at the German fait works, 
and in the procefs of boiling fea fait j but is 

*•= before the firft drawing. Then, with the ufual inftru- 
<' ment, take out fuch fait as is beginning to fall (as 
<' they term it) and put it apart • now let the pan fettle 
*' and cool. When the brine becomes no hotter than 
*' one can jufl: bear to pur one's hand into it, proceed 
*' in all refpedls as before ,• only let the quantity of 
" allom not exceed an ounce and a quarter. And in 
'^ about eight and forty hours after draw the pan." 

This is Mr. Lowndes's proccfj j only he afterwards 
direifls cinders to be chiefly ufed in repairing the fires, 
the better to prefcrvean equal heat; and by that means 
alfo propofes to fave a conliderable part of the expence 
of fcwel ; afferting that " at prefent cinders are fo little 
" valued in Chefhire, as generally to be thrown into 
'' the highways." Mr. Lowndes informs us, that in a 
pan of the fize directed by him to be ufed, there may be 
prepared at each procefs fixteen hundred pound of his fait, 
from the beft brine in Chefhire; and 1066 pounds from 
the ordinary brine of that county. Which, as the procefs 
continues above five dayp, is little more than five 
bufhels and a half of fait every day, from the beft 
brine, and a little above four bufhels a day from the ordi- 
nary brine. 

'J At Droitwich they make no ufe of hot houfes for 
their large grained fait, but only let it drain in the bar- 
rows four or five hours, and then lay it up in their 
ftorehoufes, which are Imed on every fide with boards, 
and have an inclining floor like drabs ; and with this 
treatment it becomes fufficienrly dry, 


White Salt. 107 

conflantly mixed with the next pan full of 
brine, and with it boiled into fait. 

Besides the common fait prepared, asbe- 
fore related, at moft of the Englifli brine 
works, they make a fait which they call 
fliivery fait, being of a firmer and larger 
grain than that prepared by the foregoing 
procefs, and alfo flronger and more proper 
for prefer ving provifions. In preparing this 
fait, they begin to work on Saturday night, 
proceeding exadly as in the foregoing pro- 
cefs, 'till the fait begins to form. But as 
they draw no fait on Sunday, they therefore 
only keep a very gentle fire under the pan all 
that day, and fo grain the fait with a much 
milder heat than at other times 5 taknig out 
the fliivery fait all at one draught early 
on Monday morning. 

They have alfo another kind of fait, made 
up like fugar loaves, in fmall wicker bafkets, 
and therefore called loaves of fait, or bafket- 
falt ; which is greatly efleemed for table ufe, 
being the whiteft fait, and perfedlly dry, and 
of the fmalleft grain '+. In preparing this 

'* At Salins they put the wet fait, which they draw 
from the bottoms of their pans, into wooden moulds, in 
which they dry it in ftoves, and thus form it into cakes or 
Joaves weighing three or four pounds. 


io8 ^he art of preparing^ &c. 

fait, fome ufe rofin '^ and other additions to 
break the grain, and make it fmall ; and for 
the fame purpofe others boil the brine very 
brifkly, or keep conftantly ftirring it, whilft 
the fait is forming. But the method moft 
approved of in Chefliire, is to proceed ex- 
actly as related in the procefs for preparing 
common brine fait ; and for bafket fait to 
take the fecond and third draughts, which 
are efteemed the pureil fait. Thefe draughts 
they do not fuifer to lie fo long in the pan, 
as when they make fait of a larger grain, 
but take them out before the fait can concrete 
into large cryflals j and by this means ob- 
tain a fait of a fine fmall grain. This fait they 
prefs down hard into fmall wicker bafkets, 
and when it is fufficiently drained over the 
leach trough, remove it with the bafkets into 
the hot houfe j and after it hath been there 
well dried, carry it into the flore-houfe, and 
keep it in the bafkets for fale. 

's As at the works at Droitwich. 


( 109 ) 


Of the additiojis, or feafonings iifed by fait- 

THE fait boilers, and particularly thofe 
who prepare brine fait, have long been 
accuflomed to makeufe of various fubftances 
which they call additions or feafonings, and 
mix with the brine while it is boiling, either 
when they firfl obferve the fait begin to form, 
or eife afterwards during the time of granu- 

These additions they ufe for various pur- 
pofes. As firfl to make the fait grain better, 
or more quickly form into cryflals. Se- 
condly, to make it of a fmall fine grain. 
Thirdly, to make it of a large firm 
and hard grain, and lefs apt to imbibe 
the moifture of the air. Fourthly, to 
to render it more pure. And laflly, to 
make it ftronger and fitter for preferving pro- 

These ends may fome of them be an- 
fwered by the additions made ufe of; but 
others, not ; or at leaft, might be better an- 


. I 

no T^Je art of preparing 

fwered by other means. So that feveral of 
thefe additions feem no way ufeful, but ra- 
ther prejudicial. Neither is this to be won- 
dered at ; lince this bufinefs is too often left 
to unflcilful operators, who will not eafily 
be beat out of their old road j or if they 
make any new trials, are wholly ignorant 
of the nature of the fubftances they ufe, and 
apply them at a venture, without being able 
to form any conjecfture of the effe(fts which 
may be expelled from them ; and if per- 
chance they prepare better fait than ufual, 
they immediately boaft themfelves poiTeiled 
of an extraordinary fecret, attributing the al- 
teration to the mixtures made ufe of, although 
it m.ight often, with more reafon, be afcribed 
to the flownefs or intenfenefs of the fires, or to 
other circumflances in the procefs, to which 
they do not give a fufficient attention. 

The additions moft commonly ufed to 
anfwer the above-mentioned purpofes, are 
the foliov^^ing, viz. wheat flower, rofin, 
butter, tallow, new ale, ftale ale, bottoms 
or lees of ale and beer, wine lees, and al- 

Wheat flower hath been ufed at fome 
fait works to make the fait of a fmall 

I grain; 

Whi t e S a lt. Ill 

grain ^ j which effedt it may have, either 
by being interpofed between the minute fa- 
line cryftals, and fo preventing their cohe- 
fion J or elle by rendering the brine more 
ghitinous, and fo preventing the faline par- 
ticles from moving towards each other, and 
uniting together fo eafily in that tenacious 
liquor as in a more fluid brine. 

Rosin hath long been held in great 
efteem at the Droitwich fait- works, for its 
property of making their fait of a fmall 
grain. And they are of opinion, that by 
means of this addition they obtain a whiter 
and finer fait, that meafures farther, and is 
fitter for table ufe, than any that they could 
prepare without it. And in preparing bafket 
fait, they add a larger quantity of rofin than 
ufual ^. The particles of rofin may pro- 
bably interpofe between the little cryflals of 
fait, and prevent their cohefion. But all 

' *^ If they would have it finer than it ufually corns 
*^ ofitfelf, they eirher draw it with a quick fire, which 
*' will break the corns fmall, or fprinkle the furface of 
'^ the brine with fine wheat flower, which will make 
*' the fait almoft as fine as the find which comes from 
'* it." Plot Nat. Hijl. of Staff'ordfhircy cap. li. § 105'. 

* See Dr. Raftel's account of the Droitwich falc 
works. Ph. Tr.ahr. vol. ii. p. 358, 359. 

They ftill continue to ule rofin at thole works. 


1 1 2 'The art of preparing 

additions applied for that purpofe feem un- 
necefTary j fince the fame end may be better 
anfwered by drawing the fait before it hath 
lain long enough in the pan to form into 
large grains ; efpecially if the brine be flirred 
about, while the fait is forming ; and the 
before-mentioned additions, as they render 
the fait impure, ought therefore to be re- 

Butter, tallow, and other unduous bo- 
dies are very commonly applied as addi- 
tions ; for the ufe of which many falt-boilers 
have little to plead belides immemorial cu- 
ftom. The reafon which feme of them 
give for ufing thefe undluous fubflances, is, 
that they make the brine cryilallize more 
readily i or, to ufe their terms, make it work 
or fait more kindly. And for this purpofe, 
at fome very large works, they think no fat 
fo proper as that of dogs, if I was not much 
deceived by a falt-officer, who is efteemed a 
man of integrity. Whether thefe fubflances 
have really the effects afcribed to them, can 
only be determined by proper experiments. 
'Tis however certain, that they have con- 
trary eifeds upon fome kinds of brine, both 
in England and Germany, and prevent it 


White Salt. 113 

from forming fo readily into cryftals3. And 
they were formerly ufed by feveral boilers of 
fea fait, who now find that they can make 
as good fait without them''-. 'Tis there- 
fore moft probable that thefe grofs unduous 
bodies have much the fame eflfedts with ro- 
fin, by uniting to the faline particles, and 
with them forming a kind of foapy mix- 
ture, and fo preventing, in fome meafure, 
their cohefion. When the brine is mixed 
with alcaline or calcarious falts, thefe un(5hi- 
ous fubftances may unite more readily to 
thofe falts than to the common fait, and 
with them may form a kind of foap, and 
fo may prevent them from being reduced 
into a folid form along with the common 
fait ; and thus may preferve it free from any 
mixture of falts of a different nature. But 
the Chelliire falt-boilers, who make great 
ufe of butter, do not attend to thefe its ef- 
feds, nor do they endeavour to preferve 

^ " In codione [fills] nihil acccdere debeat quod 
" pinguedinem haber, alias ad Iblidam formam non po- 
" reft facile reduci :" is a general rule of Hoffman'!), 
Ohf. Phyf. Chem. Lib. ii. Obf xvi. 

+ Thefe adduions are now every where laid afide a-t 
the marine fiUerns, excepc at thofe at Lemington and 
other parts of the weft of England, where they are ftill 
in great repure. 

I their 

114 ^^^ ^^^ ^J py^pdrhig 

their common fait pure from alcaline or cat- 
carious falts, but harden all their leach brine 
into fait, as was before related. In which 
method thefe unduous fubftances may, how- 
ever, be of fome ufe, by enveloping the al- 
caline and calcarious falts, and preventing 
them from diffolving by the moiflure of 
the air j although the common fait would 
be much better, if entirely freed from this 
faponaceous mixture. 

Several kinds of fermented liquors are 

alfo ufed as additions or feafonings ; the 

chief of which are, wine lees, new ale, flalc 

ale, barrel bottoms, or lees of ale and beer. 

Thefe additions are now generally rejedled 

by the marine falt-boilers, except in the 

weft of England. The briners, who ufe 

them, affirm that they raife a large grain, 

and make their fait more hard and iirm j, 

and fome alfo fay that they make it cryftal- 

lize or grain more readily. The Chefliire 

briners ufe feveral of thefe liquors promif- 

euGufly, as new ale and bottoms of ale 5, 

although they have very different qualities, 

and will probably have different effed:s upon 

tlie brine. Hoffman prefers the ffrongeft 

s See Mr. Lowndes* s procefs. 


WhiteSalt, 115 

and flaleft ale^ j and Plot alTures us, that it 
makes the fait of a larger or fmaller grain 
according to the degree of its fl:alenefs7. 
And indeed, the Only good effecfls that fer- 
mented liquors can have as an addition, are 
probably owing to their acid fpirit, which 
may correal the alcaline falts of the brine, 
and fo render the common fait more dry 
and hard, and lefs apt to diffolve in a moift 
air. And to the conflid; between this acid, 
and the alcaline falts of the brine, is proba- 
bly owing the ebullition obferved in the 
pan, when thofe liquors are added. As to 
the effed; which thofe liquors can have of 

^ '' Coagulationem quoque promovec fi non cerevi- 
*' fia kd zythus, auc Lobeiunfis cerevilla, quas llibacida 
" eft, auc quod melius adhuc eft vinum, fub co(fi:ione 
^' admifcerur. Quinitno pcriculum feci, & inftillavi 
*' redtificari vini fpiritus unciam loco cerevifise, quo 
" inlignem & norabilem immutanoncm ac coagulario- 
" nem animadverti, fale candidiffimo &c admodum 
" granofo evadente. Spirirus enim vini egregie facit ad 
*' omnium falium cryftallifationem., eo quod unguino- 
" fam &c unionem falinarum fpicularum impedienrem 
" fubftanciam abibrber, & fallas e liquore in fundum de- 
** jicic particulas." Hoffman De Salinis Hallenf, 
chap. vii. 

The ilhiftrious Mr. Boyle, from a fiturated brine, 
precipitated a confiderable portion of finely figured fair, 
by mixing it with dephlegmaced Ipirit of wine. See Dr« 
Shaw's Ahh. vol. i. p. 524. 

" Nat. H'lji. ofStaffordJhire^ch^^. ii. § 105. 

I 2 promo- 


Il6 ^he art of preparing 

promoting the granulation, it can only be 
very inconfiderable ; and the beft method 
of making fait of a large grain, is by means 
of a gentle heat, as will be more fully 
fliewn hereafter. If therefore it fliould be 
thought necefTary to ufe any of thefe addi- 
tions, in order to corred: the alcaline qua- 
lity of the brine, ftale ale, or Rhenifli wine, 
ought to be chofen, for new ale contains 
but little acid j and the lees of malt drink 
will probably give the fait a difagreeable 
tafle, and other bad qualities; efpecially 
when thefe dregs are evaporated to a dry- 
nefs, and hardened up with the fait, as is 
the pracftice in the common procefs of 
making the Chefliire brine-falt. And to 
thefe impurities, together with the fapona- 
ceous mixture of butter and alcaline falts, 
is probably owing the great abundance of 
thick froth or fcum, which arifes upon the 
folutions of feveral kinds of Chefliire brine 
and refined rock falts j and which I did not 
obferve upon the folutions of fome kinds 
of boiled fea fait, in the preparation of 
which none of thefe additions were ufed. 

Allum is an addition which was long 
ago known in Chefhire, and there ufed, to- 
gether with butter, to make tlie fait preci- 

Wh ite Salt, 117 

pitate from fome forts of brine, as we are 
aiTured by Dr. Leigh^, who firft taught the 
Cheshire falt-boilers the art of refining their 
rock fait. 'Tis indeed probable, that they 
formerly tried many methods in order to 
corred: the bad qualities of their fait, and to 
render it ftrong, and of a large grain, and 
fufficiently firm to endure the air. But as 
the bad properties of their fait proceeded 
from hard boiling, they found every method 
ineffedual, until they had recourfe to a 
more mild and gentle heat. And as allum 
hath long been difufed amongft them, it is 
not likely that they found any extraordinary 
benefit from it ; otherwife they would fcarce 
have negledted it, and continued the ufe of 
butter. However, a Chefliire gentleman 
hath lately endeavoured to revive its ufe, 
alTerting, that " brine-falt hath evermore 
** two main defedts, flakeynefs and foft- 
" nefs J and that to remedy thefe imper- 
" fed:ions he tried allum, which fully an- 
" fwered every thing he propofed j for it 

* '' It is obfervable the fait of fome of thefc fprings 
'^ will not eafily precipitate, but a little allum and frcfli 
^' butter will effedl it j and then it makes a larger grain 
*' and ftronger fait than any of the reft." Dr. Leigh's 
Nat. H'lji. of LancaJInre^ Chejlnre^ is'c. (publiflicd at 
Oxford in the Year 1700) p. 44. 

I 3 " reflored 

Il8 I'he art of preparing 

" reftored the fait to its natural cubical 
*' fhoot, and gave it a proper hardnefs, nor 
" had it any bad efFed whatever^." But 
whoever confiders the nature of allum will 
fcarce expedt fuch extraordinary efFeds from 
it. Neither does it here feem wanted j for 
the grains of common fait will always be 
fufficiently firm and hard, and of their na- 
tural figure, and of a large fize, and no ways 
difpofed to run by the moifture of the air, 
if formed by a gentle heat, and perfectly 
free from heterogeneous mixtures, as will 
be more fully explained hereafter. So that 
the goodnefs of the fait made by that gen- 
tleman, does not feem to be owing to the 
allum, with which it is mixed j but may be 
attributed, chiefly to the gentle heat ufed 
in its preparation. 

The Dutch, who have long fliewn the 
greateft fkill and dexterity in the art of 
boiling fait, make ufe of another addition, 
which they efleem the greatefi: fecret of their 
art. This is whey, kept feveral years, 'till 
it is extremely acid j now firft revealed to 
the Britifh fait boilers ; but long held in 
great efteem by the Dutch, for the good 

9 See Mr. Lowndes's treatife intituled, Brim fait 


WhiteSalt. 119 

effects it hath upon their fait ; which it 
renders ftronger and more durable, and fit- 
ter for preferving herrings, and other pro- 
vjfions'°. *Tis certain, that this acid liquor 
may temper the mineral alcaline falts mixed 
with their brine ; and may alfo reduce into 
a mild neutral fait the alcaline principle of 
common fait, deprived of its acid fpirit by 
the violent codtion ufed in the firft part of 
the Dutch procefs, as will be related here- 
after. The unduous particles of this whey 
may alfo entangle the calcarlous falts of the 
brine, and contribute to retain them the 
better in the bittern, and fo prevent any of 
them from forming into cryllals along with 
the common fait. And this whey, being 
itfelf a mild acid condiment, can be no 
ways prejudicial to the common fait, if 
mixed with the brine in fuch quantities, as 
to be predominant over the alcaline falts 
contained therein. 

'" The manner in which the Dutch ufe this additionj 
fee related in chap, vii, of this part. 

I 4 C H A Pp 

I2cf T'he art of preparing 


Of white fait prepared from fea water ^ and 
other fait water s^ firf heightened into a 
firong brine by the fun, 

IN feveral inland parts of Germany, where 
they have only weak fprings of fait wa- 
ter, and alfo at many places on the fea coafls 
of England where fuel is fcarce, various ar- 
tifices have been invented for converting 
thofe fait waters into a ilrong brine,, which 
they afterwards boil with culinary fires into 
white fait. 

Some have expofed thofe fait waters in 
open vefTels to be congealed in part into 
ice J and as the water freezes, the fait is in 
a great meafure expelled out of it into the 
uncongealed liquor ; which thus, during 
hard frofls, is converted into a ftrong brincf. 

But the fame effedt is with greater con- 
venience and certainty performed by the 

* *' NonnulJi falfilaginem frigori exponunt, atque 
*' gelari finunr, & apciflima efthuic fcopo ilia, quae duas 
" aur unam cum dimidia falis uncias comprehendit (fcii, 
^^ in falfjlaginis lib. i.) qu£e enim tres, quatuor, j;ut quin- 
*' que uncias cuftodir, nunqu:-!!! frigore denfatur: di- 
^'•' fnidia vero, aut una unciafoera, tota in glaciera abit/* 
Hoffman De Salln, Hall. chap. vii. 


Wh it e Salt. 121 

heat of the fun, and the operation of the 
air. For this purpofe, in feveral parts of 
Germany they ere6t fumptuous edifices of 
wood. One of which works at Soda, near 
Frankfort on the Main, with the method of 
preparing brine therein, is defcribed by an 
ingenious traveller, in the following words* : 
" It belongs to Mr. Malapert, and has 
been wrought above fixty years. — There 
rifes at the foot of fome little hills which 
produce very good wine, a fpring of wa- 
ter that is fo very little brackifh to the 
tafte, that one will hardly think it poffi- 
ble to fetch much fait out of it, yet it has 
fuch a taflie of fait, that there was room 
for induftry to prepare this water fo, that 
without fuch an expence of fire as would 
eat out the profit, it might turn to a good 
account. — The meadow that lies in the 
level with this fpring is impregnate with 
fait, iron, nitre, and fulphur, but fait is 
that which prevails. Firfl then, a pump 

* See Supple7ncnt to Bljhop Burnefs Letters. Let- 
ter iii. 

Thefe the Germans call Leck-oder Gradier-wercke, 
and have many of them ; but they are not all conftruded 
alike j for where the water is falter, they have fewer 
cifterns; in fome works only one, as at Bcvieux or 
Roche, as hath before been related. 


122 'The art of preparing 

" is put upon this fpring, which is managed 
*' by a water-mill, and throws up the wa- 
" ter about fifteen feet high ; and then it 
" goes by a pipe into vail machines, that 
" are made to receive it. 

" There is a great piece of ground in- 
" clofed, in which there are 24 vaft chefts 
*' or cifterns for the water, in two ftories, 
** twelve in a flory, the one juft over the 
*' other ; they are about feventy foot long, 
" twelve broad, and two deep ; over every 
" one of thefe there is a roof of boards fup- 
" ported by wooden pillars twelve foot high, 
" which covers them from rain-water, but 
** yet the water within them is in a full 
" expofition to the fun j thofe roofs are 
" hung with ftraw, upon which fome that 
" manage the work are often throwing up 
" the water, fo that a great deal of the 
" phlegm is imbibed by the flraw, and the 
** more fixed parts fall down. According 
" to the heat of the feafon, this evapora- 
" tion of the watery parts goes quicker or 
** flower. There is a gage, by which they 
" weigh the water, and fo they know how 
" the evaporation advances ; it is of filver, 
" and is fo made, that according to the 
^' weight of the water it finks into it to 

" fuch 

Whit e Salt. 125 

" fuch a depth, and fo by the degrees 
*' marked upon it they know how heavy 
" the water is. According then to the heat 
" of the feafon, and the progrefs of the e- 
** vaporation, they let the water out of one 
'' cillern into another, by a pipe ; and 
*' when it hath pafl through the twelve 
" that are in the upper flory, then it is 
" conveyed down by pipes into the twelve 
*' that are below y and in them all they con- 
" tinue ftill to throw up the water upon 
" the withs of ftraw that are over head. 

" In a word, this evaporation difcharges 
" the water of fo much of its phlegm, 
" that the fame quantity of water that 
" weighed one ounce, when it was drawn 
" from the fpring, weighs fix ounces in 
" the lafl cheft^. And all this rolling about 
** of the water from cheft to cheft lafls 
" fometimes not above twenty days ; but, if 
" the (tafon is only moderately hot, it will 
*^ be longer a-doing : fometimes it will not 
" be done in a month's time ^ After that 

' This is certainly an error ^ he probably means that 
only one fixth pare of the vv'atcr remains, the rell be- 
ing evaporated from the lalt. 

^ Hoffman, (peaking of this method, fays, '' T^otum 
*-« negotium m;nus exortaro fucccditj nifi ficciras per 

'' the 

124 ^^ ^^^ of preparing 

'* the water is brought to a very confide- 
" rable degree of faltnefs, it is conveyed 
*' into two great caldrons that are thirteen 
*' foot long, ten broad, and three and an 
" half deep, under which there are vaft 
" furnaces, where, in a mofl: violent fire of 
*- eleven or twelve hours, the water receives 
*' its lafl evaporation j and when that is 
*' done, the fait, which is become thick, 
*' but is ftill moift, is taken up in bafkets 
*' of willows, and placed about the wall of 
" the furnace, fo that the humidity that 
" remains in it drops out, and it is brought 
" to its lafi: degree of perfection. — There 
" are vafi: quantities made of it in hot and 
" dry fummers, for the chefls are kept al- 
" ways full ; and thus all Franconia is fur- 
" niflied with fait of its own production, at 
" very moderate rates." 

But the Englifli elaborate fea water into 
brine by a much eafier and lefs expenfive 
method than that before defcribed. This 
is called raifing or heightening fea water by 
the fun 3 and there are many large works at 
Lemington in Hampfliire, and in the ifles 

" annum regner, & commodiffime tantum adornarur 
** vento boreali &: oricnrali fpirante, vernaii atque oeili- 
'* vo, non autem hiemali tempore. 


White Salt. J25 

of Wight and Portfea, alfo about Pool in 
Dorfetfhire, and nigh Toplliam in Devon- 
fhire, where this method hath long been 
pradifed, to the great advantage of the pro- 
prietors of thofe works ; who though they 
boil their fait with Newcaftle coal, yet can 
afford to fell it cheaper at London than 
that which is boiled from fea water in the 
neighbourhood of Newcaftle; where the 
coal does not coft above a quarter part of the 
price paid for it by the owners of thofe fait 
works in the weft of England. 

The works in which the fea water, is 
heightened into brine, are called fun-works, 
or the out- works ; and are conftrudled near- 
ly after the following manner 5. 

A PROPER lituation, on a flat downs, or 
ouzy beach is chofen, from which, if there, 

5 The account here given is the beft that I have been 
able to obtain, having been compofed from the re- 
lations of feveral fak-officers, compared with a few 
hints, which Mr. Brown, Harris, Chambers and others 
have given us relating to thefe works. I am very far 
from offering this as a perfedt and eyact defcription • 
but as one from which an idea may be formed of the 
general contrivance of thefe works. It is to be wiflied 
that fome perfon of publick fpirit would favour us with 
a more perfedl: account of them ^ which was much 
defired by the Royal Society lixty or feventy years 


126 The art of preparing 

be occafion, the fea is barred out by a mole* 
Within this mole, there is a large refervoir 
or feeding pond, which has a communica- 
tion with the Tea by a fluice j and adjoining 
to the refervoir, a long trench 5 and parallel 
to the trench feveral fquare ponds, nine or 
fometimes twelve in number, all placed in 
a row, the whole length of the trench j and 
parallel to this row, two other rows of 
fquare ponds, equal to thofe in the iirft row 
in number and dimenfions. Thefe ponds 
they call brine pits. Beyond the third row, 
is a row of larger ponds three in num- 
ber, with each of which, three or four 
of the brine pits in the third row communi- 
cate by narrow openings. Thefe they call 
fun pans ; and thefe three fun pans often 
communicate with another larger pond, 
which they call the common fun pan, from 
which the brine flows into large covered cif- 
terns (made very tight of brick and clay) 
adjoining to the boiling houfe. All thefe ponds^ 
with the partitions betv^een them, ufually 
cover about two acres of ground. 

The bottoms of the ponds, are in feve- 
iral places, as at Lemington, made of an 
ouzey mud ; to make which hold water, 
they tread it down very hard with boots 


Wh ite Salt. 127 

that have flat foles, and afterwards lay it 
very fmooth, and in the brine pits and fun 
pans, cover it with fea fand ; which pre- 
vents the ouzey bottoms from cracking when 
dry, and makes them better retain the fun's 
heat, and more readily exhale the watery 
vapours. The bottoms of all the pits form 
an inclined plane, which is higheft at the 
refervoir, and loweft at the common fun 
pan i but where the ground will not admit 
of fuch a declenfion, the water is raifed up 
by a fcoop and trough, which turn upon an 
axis J and the fcoop receiving the brine from 
the lower pond, when it is raifed up, it falls 
into the trough, through which it runs into 
the higher pond adjoining. The partitions 
between the ponds are all of mud and earth, 
a foot and an half or two feet broad, and 
have little openings by which the pits commu- 
nicate one with another ; and thefe openings 
are clofed with mud, when occafion requires. 

The fea water being received into the re- 
fervoir at full fea, is from thence let out, as 
occafion requires, into the trench ; and from 
the trench, into the firfl row of brine pits j 
and when they are filled to a certain height, 
the openings between them and the trench 
are dammed up with mud. When the wa- 
ter hath flood a due time in this firii row of 
I pits. 

128 ^he art of preparing 

pits, it is let out into the fecond row, whicli 
before were empty, and the bottoms of them 
expofed to the heat of the fun. After a cer-^ 
tain time, which is longer or fliorter in pro- 
portion as the evaporation advances, the 
brine is let out of the fecond into the third 
row of pits ; and about the fame time the 
firfl: row of pits are again filled 3 the feveral 
rows being thus emptied and filled alternate- 
ly. When the brine is fufficiently evapo- 
rated in the third row of brine pits, it is fuf- 
fered to flow into the fun pans > and after- 
wards into the common fun pan j where 
they examine its weight by means of glafs 
hydrometers ; and when they find it of a due 
ftrength, they draw it from thence into the 
cifterns ; where it is ftored up till they have 
an opportunity of boiling it. 

The lea water, which was received into a 
row of the brine pits, and carried forward 
together through the whole work, is called a 
courfe of brine. And fometimes when the 
weather is excefUve hot, it is brought to its 
full ilrength, and performs its whole courfe 
from the trench to the ciflern in twenty four 
hours. But when the weather is lefs favour- 
able, it requires a much longer time for its 
paiTage. And fometimeSj when they obferve 


Whi T E Salt. 129 

{howers approaching, they draw it off into 
the ciftern before it is brought to its 
full ftrength. In this courfe the fait water 
ftands deeped in its firfl row of brine pits, 
and gradually fhallower in the feveral pits, 
till it arrive at the fun pans, where it flands 
Ihalloweft j in the common fun pan it is fix 
or feven inches deep, being there deeper than 
in the fmaller fun pans. 

And after this manner, if the feafon prove 
favourable, they make as much brine as 
keeps them boiling till nigh Chriftmas j after 
which they repair their pans and furnaces, 
and prepare their Epfom fait from the bittern, 
and begin again to make brine about April. 

The pans in which they boil the fait at 
Lemington are of lead, of a fquare form, and 
fmaller than thofe before defcribed for boiling 
fea water* into fait. They ufually have four 
of thefe pans in a faltern, all placed in a row, 
with a diftind; furnace to each of them. 
The chimnies are carried up by the fide of 
the wall, which divides the boiling houfe 
from the forehoufe j and the fmoke is con- 
veyed from each furnace into thefe chim- 
nies by two flues, one on either fide of the 
mouth of the furnace. To each of thefe 
flues is fitted a regifter, or plate of iron, 

K placed 

i^o T^he art of preparing 

placed horizontally, which, by means of 
a handle, may be drawn out, or thrufl in 
over the flue, fo as to clofe it and prevent the 
fmoke from afcending through it. And 
by means of thefe regifters, and vent-holes, 
and doors to the mouths of the furnaces and 
aili pits, they can regulate the fires in the 
exadtell: manner, and can damp them while 
the fait is graining, or fmother them quite 
out, if they fee occafion. 

In the boiling houfe they have a chimney 
to convey off the vapours from each pan j it 
is a fquare funnel of boards, which is not 
carried down fo low as the pan j but room is 
left below it for the falt-boilers to draw the 
fait, or to do any other bufinefs about the 
fait pan. There is only one long walk in 
the boiling houfe, on the fide of the pans 
oppofite to the mouths of the furnaces ; and 
between this walk and the wall, are placed 
large wooden troughs, with many little holes 
in their bottoms ; into which troughs the 
fait, when drawn out of the pans, is put to 
be drained from the bittern. Below thefe 
troughs others are placed to receive the bit- 
tern ; and in them feveral fiiicks are fixed 
ere(^, to which the cat fait adheres in large 


Wh I te S a lt. 131 

cryftals^. This (as I am informed) is the 
general conftrudlion of the Lemington falt- 
erns, which feems very artful and commo- 

The procefs for boiling fait is much the 
fame here as at the brine works. Only it 
may be proper to mention a few particulars 
in which there is a difference. And firfl, at 
the Lemington works they ufe no clarifying 
mixtures, which are there unneceflary, as 
the brine commonly ferments in the cifterns, 
and by that means the texture of its vifcuous 
matter is broken, the more grofs parts 
whereof, together with the light mud, fub- 
fide to the bottom of the ciftern. They 
boil the brine violently till a thin fkin of fait 
appears on its furface '' ; and then damp the 
fire, and carefully fkim off this H^in, and alfo 
take out the calcarious earth and call it away* 
This earth they do not colledl into fcratch 
pans, as at moil other works, but fuffer it 
to fettle to the bottom of the pan, and rake 

'^ The cat-filt is common fair, which concretes round 
thefe fticks in large clear lumps j it holds fome of the 
bitter purging fait j it is very fharp and pungent \ and, 
when powdered, white j and is ufed by forre for 
the table j but the greatell confumption of it is among 
the cake foap-boilcrs. 

^ They fay then that the brine begins to yew. 

K 2 it 

J 3- 2 ^^'^^ ^^^ of preparing 

it to the fide, and thence draw it out. The 
brine being cleared from the fcratch, they 
then add to it butter, and other feafonings ; 
and afterwards proceed to grain the fait with 
moderate fires, although they grain it more 
haftily here than at moft works, commonly 
reducing three pans full of brine into fait in 
twenty four hours. When the fait hath re- 
mained in the troughs fix or feven hours, it 
is taken out j and, without any other pre- 
paration, laid up in the flore houfes for 

' A falt-boiler with an afliftant attends four pans, and 
alfo prepares the brine in the outworks. The fair-boiler 
for wages receives is. 6d. per quarter, or fix fhillings 
per tun for nil the fak made j out of which he pays the 
alTiftant. Of this they reckon lo^. per quarter for 
boiling the fait, and 8 d. for preparing the brine. They 
can afford to fell the fait at thefe works, free of excife, 
from I /. to 1 /. 6 s. per run, according as the feafon 
has been more or Ids favourable for making it, or ac- 
cording as there is a demand for it. Whereas at Nevv- 
caftle the profit is very fmall, when they fell their falc 
for 30 J. per tunj although it is fometimes fold there 
for 27 J. 


White Salt. 133 


Of white fait made from afli'ong brijie drawn 
from earths^ fands^ and Jloms impregnated 
iiDitb fait. 

TH E ftrong brine or lee which is drawn 
from faHne earths, fands, and flones ', 
and afterwards boiled into fait, is prepared 
after different ways. 

In feveral parts of Germany, as at Inn'- 
thall ^ nigh Infpruck in the county of Tyrol, 
and at Halleim in the archbiflioprick of 
Saltsburgh, alfo at feveral places in the Up- 
per Auftria, there are deep mines, in which 
they dig fait mixed with much mud and 
earth. This impure fait, or faline earth, 
they do not draw out of the mines, but break 
into pieces, and caft it into pits at the bot- 
tom of the mines ; thefe pits they fill up 
with water, and when the water has ll:ood 

* Brine prepared in this manner is called Dilurum by 

* The mines are faid to be four miles diftant from 
the city, and the brine is conveyed all rhat way through 
troughs, to the falterns. At thefe works, when Mr. 
Addifon was there, they made at the rate of eight hun- 
dred loaves of fak a week \ esch loaf being four hun- 
dred weight, 


134 ^f^^ ^^^^ ^f pycparlng 

in them fome weeks, it becomes a fully fa- 
turated brine, each pound of it having ab- 
forbed fix ounces of fait. This ftrong brine 
is then drawn out of the mines, and conveyed 
through wooden channels to the falterns, and 
boiled in iron pans into white fait, for which 
they find a fale in Bavaria, Stiria, Carinthia, 
and in fome of the Swifs cantons, and 
amongfl: the Griffons ^. 

In other places they do not dig out thefaline 
earths and ftones, but introduce frefli water into 
the places where they are lodged, and the water 
being impregnatedwith thefalt is thence drawn 
out, and evaporated in proper velTels ^, 

3 Vide Hoffman Dc falinis Hallenf. Cap. ii. ec iv. 
Et Ohf. phyf. cbem. Lib. ii. Obf. xvi. 

" On voir aulTi dans I'Auftriche f-iperieure, au lieu 
*' appelle Mund, (ou il y a des monragnes', qui ont des 
" veines remplies de fel) de fomptueux edifices dc bois, 
" pour conduire les eaux infipides dans les endroits ou 
'' eft ce (el, afin que la diflblvanr, elles en prcnncnt Ic 
" gour." Comce Marfiili, Hiji. de la Met; p. 22. 

+ A French traveller cakes notice that the waters at 
Roche are infipid before they pafs over veins of fait, 
v/hereof they inlhntly take the acrimonious favour. The 
galliery cut through a rocky mountain for the pafTage 
of this fait water to the lalcern, he fays, is five hundred 
tathoms in length. 

Saxa ipfa (in putei cuniculis, magno labore excifis) 
falinis particulis referta ^ qux indicio funt mani-tfto efTe 
f-il hoc Ba(fliacum foffilc, ab aqua fontana folutum, 
rurfumve arte concretum. Scheuchzeri Iter Alpin. 
lepti?nu?n, on the fame fait works. 


White Sal t. 135 

In other places a llrong brine is extraded 
from fea fand j which brine is afterwards 
boiled into white fait. There are very con- 
fiderable works of this kind at Mount St. 
Michael, and other places upon the coafls 
of Normandy ; where this fait is made fo 
cheap, that it is often exported to London ; 
although loaded at that market with a hea- 
vier duty than Britifh fait. There were 
formerly feveral works of the fame kind at 
Wire- water, and Medop in Lancafhire, and 
at Milthorp in Weftmoreland ; at which 
places, pit-coals being fcarce, they boiled 
the fait with turf fires ; but fince brine fait, 
and refined rock fait have been made in fuch 
plenty in Lancafhire and Chefliire, all thofe 
fand works have gone to decay ; and that 
method is, in thofe parts, intirely laid afide; 
except at one or two very inconfiderable 
works nigh Ulverflone in Lancartiire. 

The fand from which they prepare the 
brine at the works nigh Ulverflone, is col- 
lected on flat fandy fhores, on thofe parts 
of them which are only covered with fea 
water in the high tides 'which flow two or 
three days before, and three or four days 
after the full and new moon ; for thofe parts 
of the fands which are overflown by the 
K 4 neap 

136 I'he art of preparing 

neap tides, are feldom fufficiently dried, and 
are at too great a diflance from the falterns. 

This fand they coUedt in flats and wafli- 
es, or in parts of the fands which are per- 
fectly plain, and in little hollows where the 
fea water is left, and either finks Into the 
fand, or is dried up by the heat of the fun, 
leaving the fait behind. The fand is only 
colleded in dry weather, when the ffca wa- 
ter hath been exhaled from it by the fun, 
and the rains have not waflied the fait out 
of it. At fuch times, and in fuch places 
they rake up the fand into heaps, to the 
depth of two or three inches, and convey 
it to their works in carts 3 laying it up in a 
large heap, where it is expofed to the wea- 
ther, and fubje(5t to be much injured by 
rains. They therefore work it up with all 
diligence, and rarely boil any fait in the 
winter feafon. 

In order to extrad the fait from the fand j 
adjoining to the faltcrn, they dig a pit eigh- 
teen feet long, three feet broad, and one 
foot deep. The bottom of this pit they co- 
ver with rufhes, of flraw, and then fill it 
up with the fait fand from their heap j up- 
on the fand they pour fea water, which they 
take into a pond or fump at fpring tides ; 


Whit e Salt. 137 

the water fmbibing the fait from the fand, 
filtrates through the ru flies or ftraw, and 
runs through a pipe from the bottom of the 
pit, into a ciflern placed in the boiling 
houfe. They continue pouring fea water 
upon the fand, fo long as the brine in the 
ciilern will bear a hen's egg to a certain 
height. And thus having extrafted mofl of 
the fait from the fand, they remove it, and 
fill up the pit with frefh fand from their 

The brine being thus prepared, they boil 
it with turf fires in fmall leaden pans j in 
which they only make about two gallons of 
fait at each procefs, which is ufually per- 
formed in four hours. They ufe no clari- 
fying mixtures, but take off a fcum, which 
arifes in great plenty when the brine begins 
to boil 5. They drain their fait in wicker 
bafkets, which they hang up in the hottefl 
part of the faltern. After each procefs, 
they throw out the bittern that remains in 
the pan 3 and about once a day, while the 
pan is hot, remove it from the fire, and 
beat it with a wooden mallet, and thus free 

5 We are told that in Normandy, while the fair is 
graining, they ftir it continually with wooden ladles. 



i;^^ T'/je art of preparing 

it from the calcarious cruft which adheres 
to its bottom and fides ^. 


Of refined rock fait. 

TH E pradice of refining rock fait, 
and converting it into white fait, hath 
long prevailed in feveral countries, parti- 
cularly in Great Britain, Hungary, and Po- 

The Cheiliire foifil fait is efteemed un- 
fit for domeftic ufes, untill it hath under- 
gone this preparation'. Vaft quantities of 
it are now refined in that county, being firft 

^ This fliews that Dr. Lifter was miftaken in fup- 
pofing, that the fcratch was formed by boiling the brine 
in iron pans ,• becaufe he obferved none in the Droic- 
wich brine, which was boiled in lead pans. 

* We are informed in the Philofophical Tranfa£lions^ 
that the mines out of which this fait is dug, were firft 
difcovered in the year 1670, in boring for coals in the 
liberties of William Marbury of Marbury, Efq; where 
it lay thirty-three or thirty-four yards from the furface, 
and that from it there iflued a vigorous fharp brine, 
ftronger than any then ufed in Chefliire. 

At prefent many mines of this fait are wrought nigh 
Northwich, by feveral proprierors, moft of whom are 
united in one compjny for ihe more convcincnt carry- 
ing on of their works. 


Wh it e Salt. 139 

diflblved in weak brine ^. Large quantities 
of it are alfo carried in boats down the rivers 
Weever and Merfey ; and either refined at 
Dungeon and Leverpool, where they take 
up fait water out of the river Merfey at full 
fea, to diffolve it in ; or elfe fhipped at Le- 
verpool, and tranfported by fea along the 
Britifh coafls, and into Ireland, to places 
where it is boiled into white fait with fea 

The works where they boil rock fait are 
called refineries j at thofe works at Dungeon 
and Leverpool, the rock fait is broken 
fmall, and thrown into leaden cifterns, and 
there difiblved cold in fea water. In thefe 

* The refined rock and brine falcs arc exporred from 
Leverpool in very large quantities to many parts of 
Great Britain and Ireland ; and alfo to the AmcricaH 
colonies, more efpecially fince the commencement of 
the prefent war, whereby the inhabitants of thofe colo- 
nies have been prevented from fupplying themfclves 
with fufficient quantities of bay filt. 

White (alt is ufually fold at Leverpool for about one 
Pound per tun, exclufive of the duty. 

3 It was provided by a<fl of parliament, that no rock 
fait fhould be refined at any works in Great Britain, di- 
flanc above ten miles from the mines v^^here it is got, 
ex'cept at fuch works where it v/as refined before the 
faid acfl took place. By another adf, a large duty was 
laid upon rock fait exported to Ireland ; but the time 
for which that duty was impofed being expired, and the 
adt not renewed, many refineries have lately been ereflcd 
in that kingdom, 


140 TZv art of preparing 

cifterns the flrong folution remains twenty- 
four hours to fettle, and is then craned off 
from the fediment into the lalt pan, and 
there boiled into fait, as is praclifed with 
natural brine, it being clarified in the fame 
manner, and mixed with the fame addi- 
tions. During the procefs, large quantities 
of fcratch fall from it, as from natural 

The leach brine is not thrown away as at 
the marine fait works, but is preferved and 
mixed in the pan with the folution of rock 
fait, and with it boiled up, as at the Che- 
fhire brine works. 


Of the "Dutch method cf preparing fait upon 

IN Holland and Zealand, the Dutch for 
ages paft have pra6lifed the art of refin- 
ing fait with the greateft fuccefs j and to 
their extraordinary fkill in this art, are in a 
great meafure owing the advantages which 
they have over other nations in the herring 
fifhery ; lince fifh preferved with their re- 
fined fait, look much cleaner and fairer than 
thofe that are cured with bay fait, and keep 


Whi te Salt. 141 

much better than thofe preferved with any 
other kind of white fait. And although 
inquiries into this art feem of great impor- 
tance to a trading maritime nation, yet they 
feem to have been almofl wholly neglected 
by my countrymen ; or if any of them have 
got a knowledge of this art, they have con- 
cealed it out of views of felf-intereft, or 
other private motives. 

But as I am perfuaded, that a more 
general knowledge of this art may be of 
public ufe, and being under no tie of fecre- 
cy J I fliall therefore acft in this as I have 
done in all other cafes, and faithfully re- 
veal fuch particulars relating to this art, as 
I found means of obtaining during my refi- 
dence in Holland, from feveral perfons of 
credit, who had the beft opportunities of in- 
forming themfelves about it. 

The Dutch prepare two kinds of refined 
fait ; the one of a fmall grain for table ufe, 
which they call butter fait, and export in 
large quantities up the Rhine, and into 
other parts of Germany. .The other fort is 
a very ilrong pure fait, of the largeft grain 
of any boiled fait now made i and this they 
call Saint Ubes or Lilbon fait j from its re- 


142 I'he art of preparing 

femblance to the pure bay fait brought from 
thofe places: 

The fait which they refine is altogether 
marine bay fait ; which they have chiefly 
from France and Spain. As from Rochelle, 
Soufton nigh Bayonne, and Cadiz \ They 
find by experience, that any one kind of 
bay fait does not anfwer their purpofe fo 
well as feveral kinds mixed. They there- 
fore frequently mix three parts of Spanifh 
fait with one of that of Soufton ; which laft 
is much efteemed for its great flrength, but 
is very dirty, and of a bad green colour, 
and does not cofl above half the price of the 
Spanifli fait j however, they efleem a certain 
proportion of it neceffary, but are obliged to 
ufe it fparingly ; for the operators affirm that 
more than a quarter part of it would render 
the refined fait, black and unfit for fale. 

For diifolving the bay fait they ufe fea 
water, which they bring to Dort and Rot- 
terdam in large lighters from below the 
Briel or Helvoet. Out of thefe lighters it 
is craned into cellars, where it is impreg- 

• For fome time indeed they ufed confiderable quan- 
tities of the Englifh rock fak • but I am informed that 
the ufe of it was prohibited by the States • who found 
that the fait which they prepared with it was not fo good 
as the refined bay fait. 

^ nated 

White Salt. 143 

nated with the bay fait to a certain degree 
of ftrength, of which they judge by hydro- 
meters made for that purpofe. 

After the heavy drofs of the fait hath 
fettled to the bottom of the cellar, the clear 
brine is pumped up into the fait pan through 
a mat, which retains the light fcum, ftraws, 
or other impurities which ftill may float 

Their fait pans are made of iron, com- 
monly of a round form, and of an extra- 
ordinary magnitude ; being ufually forty 
feet in diameter, and eighteen inches deep > 
and are bound round very flrongly with 
large bars of iron =. 

These pans are placed over a hearth fur- 
nace. The fuel which they burn in thefe 
furnaces is altogether turf, which they en- 
deavour to procure as dry as poflible ; wet 
turf being found to corrode their pans, and 
to make them confume more quickly than 
that which is dry^ 

* I have been rold, thar, when thefe pans are new, 
they wafl\ them over with Hme and water, which pre- 
ferves the pan from ruft, and never wears off. But it 
feems more probable, that they only fill up the joints 
with lime, as we do in England. 

3 It hath been reported, that the Dutch ufe pit-coal. 
at their ll^lt works. lu is true indeed, that for all works 
where pit-coul is necelTiry, as for light- houfe?, ?hCs- 



144 I'be art of preparing 

The pan being filled with brine, and the 
fire kindled, the brine is made to boil vio- 
lently, and if any fcum arifes they take it 
off, but do not ufe any clarifying mixtures* . 

A LITTLE before the fait begins to form, 
they flacken the fire, and add to the brine 
the bignefs of a walnut of the frefheft but- 
ter 5, and half a pint of their four whey be- 
fore defcribed, taking care to ftir it well 
about, that thefe feafonings may be every 
where equally mixed with it. They then 
fhut up the doors and windows of the fal- 

houfes, fmiths forges, the States wifely encourage the 
importation of pit-coal, and fufFer it to be ufed duty 
free. By which means the Dutch manufadurers have 
thofe coals cheaper at fuch works than the Englifli, 
when only carried from one of our ports to another. 
But the cafe is different when pit-coals are ufed in Hol- 
land for common fires, or in works where they are not 
ablolutely wanted ; for then they are loaden with a 
heavy duty, \\\ order to prevent the confumption of a 
foreign commodity. And, as in refining fait, the Dutch 
chiefly apply (low and regular fires, turf feems as proper 
for that ufe as pit-coal. It is therefore moft likely, that 
agreeably to the wife policy of their government, and 
the informations which I have received, the Dutch, in 
refining fait, ufe fires of turf, which is the product of 
their own country. 

♦ One gentleman informed me, that they clarified 
with whites of eggs, but two of the Dutch fait boilers 
aflerted the contrary. 

5 I have reafon to fufped that the butter is added only 
when they make their table fait, which they call butter 


White Salt; 145 

tern, (o that no frefh air can blow into the 
pan ; and the houfe becomes very hot 5 and 
is thus kept clofe all the time that the fait 
is graining^. 

If they make table fait, the brine is fuf- 
fered to fimmer gently during the granula- 
tion, and the whole procefs is finifhed in 
twenty-four hours. 

But when they make their flrong fait 
for curing provifions, they only ufe an ex- 
tremely mild and gentle heat, fo that three 
days are ufually fpent in the procefs, before 
the brine is fufficiently evaporated. 

In both cafes, they fuffer the fait to re-* 
main in the pan 'till the procefs is finiflied, 
and then rake it to the fides with wooden 
rakes, the handles of which are twenty feet 
long. It is then taken out, and, after the 
brine h^.th drained from 't in wooden drabsg 
it is fit for ufe 7. 

^ At mai.-y of the German fait works, where they boii 
brine ialr, they alfo exclude the cold air from the pan, 
while the fait is graining, by boards placed on every fide 
of it, after the manner direifled by Agricola. 

" The table fait is ufually fold at the works for about 
twenty-four fty vers, and the ftror.g fait for about thirty 
ftyvers the bulliel; and their bufhel is faid to contain 
about fifty pounds of the table fait, and eighty pounds of 
the ftrong refined fait. There is probably a greater du- 
ty upon the table fait than upon the ftrong refined fait, 
which makes the latter cheaper than the former. 

L The 

146 ^he art of preparing &c. 

The mother brine, of which there re-' 
mains a large quantity in the pan after the 
ilrong fait is made, as alfo that which drains 
from the fait in the drabs, is referved to be 
boiled up for table fait, being never ufed in. 
preparing the flrong fait. 

But the mother brine of table fait, after 
each procefs becomes more fharp and bit- 
ter ; and is therefore, at certain times, 
thrown out as ufelefs j great care being ta- 
ken to wafh it well out of the pan before 
they propofe to make their ftrong refined 


( H7 ) 


To the foregoing 



Of the qualities of the fever al kinds of bay fait, 

HAV I N G, in a brief manner, related 
the various methods of preparing 
fait, as now moft commonly prac- 
tifed ; it will in the next place be neceffary 
to fubjoin a lliort account of thofe qualities, 
which fait acquires chiefly from the diffe- 
rent ways of preparing it ; that fo, thofe 
methods may be chofen by which a fait is 
made moft proper for the ufe of the table, 
Or for preferving provifionsj and thofe me- 
thods may either be amended or rejected, 
L 2 by 

14B Of the qualities of the 

by which a fait is prepared lefs fit for the 

abovementioned purpofes. 

And firft j the feveral kinds of bay fait 
differ from each other, chiefly in the follow- 
ing particulars, viz. 

1 . In the fize of their cryjlah. For bay 
fait, in proportion as it lies a longer or a 
fhorter time in the pits, or as the folar 
heat, or force of the air is more or lefs pow- 
erful, will be formed into greater or fmaller 
cryflals. Upon thefe accounts the French 
cream of fait, and the blown fait of the Ifle 
of May, which are fkimmed off" the furface 
of the brine, are of the leaft grain. The 
Portugal fait is commonly of a larger flioot 
than that of France ; and that of Tortuga, 
much larger than that of Portugal. 

2. hi purity. For there is fcarce any bay 
fait which is not mixed with feveral hete- 
rogeneous fubftances ; as flime, mud, fand, 
and clay, which are raked up with it from 
the bottom of the pits where it is made, or 
mixed with it whilfl: it lies on the ground 
in heaps. There are fome kinds of bay 
fait which are mixed with bitter purging 
fait, and probably with other falts. From 
all which mixtures it acquires peculiar qua- 

3. For 

Jeveral kinds o/'BaySalt. 149 

3. For from the mixture of clays and 
earths it acquires various colours. The French 
bay fait is commonly grey j where the bot- 
toms of the pits are of blue clay, it is more 
white ; where of a red clay, it hath a red- 
difh cafl J and that of Soufton, nigh Bayonne, 
is of a greenifh colour. The Portugal and 
Spaniih falts are whiter and purer than the 
French, but yet retain a confiderable mix- 
ture of mud and dirt. In general, all fait 
when dry, is more white j when moift, 
more pellucid. 

4. Some kinds of bay fait are more apt to 
contrast a' moiftiire from the air than other 
kinds. And this either becaufe the fait is 
of a fmaller grain, and comes into contad: 
with the air in a greater number of points ; 
or elfe, becaufe of fome mixture of calcari- 
ous, or alcaline falts, which greedily imbibe 
the aqueous moifture. 

5. Some kinds of bay fait are diftin- 
guifhed by their Jmell-, as the Hamplliire 
and Portugal bay falts, which have a fine 
violet flavour when ftored up in large heaps ; 
probably from the oleaginous or fulphureous 
particles mixed with fea water, or imbibed 
by it in the ponds, and there altered and 
fubtilized by fermentation. 

L 3 6. Bav, 

t^o Of the qualities of the 

6. Bay fait, from the variety of fub- 
ftances mixed with it, differs greatly in tajie, 
as well as in other qualities. Thus, accord- 
ing to Galen, the fait of the Lake Afphal- 
tites, or Dead Sea, is extremely naufeous 
and bitter -, probably from bitter purging 
fait, and other mixtures ^ The fait made 
at the fprings of Peccais in Languedoc hath 
alfo a bitter tafte ''. Whereas the fait made 

' As from bituminous fubftances, which abound in 
other fait waters, as well as in thofe of the Dead Sea. 
The reader may give what credit he thinks fit to the 
following inftance from Pliny. *' Fit [fcil. fal com- 
*' munis] et e puteis in falinas ingeftis. Prima dcnfatio 
*' Babylone in bitumen liquidum cogitur, oleo fimile, 
'* quo & in lucernis utuntur : hoc dctracto fubell fal." 
!'^at. Hijl. lib. xxxi. cap. vii. 

* Comte MarfiUi fays, that this fait is made of falt- 
water drawn from deep wells, and gives the following 
account of it. 

" Le gout du fel, que Ton fabrique a Peccais, eft fale, 
*' amer, 6c fi dcfagreable, qu'il n'eft pas poflible de 
*' s'en fervir, la premiere annee. On a peine dc s'y ac- 
^' coutumer la feconde,' mais on dit, qu'ii la troifieme 
*' il fe rend fupportable ; & qu'a la quatrieme fon amer- 
*5 tume eft fort peu fenfibie j & va toijjours ainfi, en 
*' diminuant a proportion du progres des annecs. On 
** a coiitume dans ces falines d'y difpofer la recolte de 
*^ I'annee, en mafTes, auxquelles on donne le nom de 
^* I'an, qu'elles ont ete faites, Elles reftent de la forte 
"^ abandonnees a I'injure du tcms, qui purge le fel de 
*' cette amertume pendant trois ans tout au moins, avant 
f^ (jue Ton commence a le diftribuer. 

fi'veral kinds of Bay S alt . 151 
ill the Cape de Verd iflands. Salt Tortuga, 
and in many other places from the water of 
fprings and lakes hath a very agreeable tafte. 
Although bay fait made from the fame kind 
of water in different pits, or from other dif- 
ferent circumftances attending its prepara- 
tion, may differ greatly in tafle as well as 
in other qualities. Thus the marine bay 
fait, although commonly palateable, may 
fometimes acquire a bitter tafle, from cal- 
carious falts mixed with it ; as may happen 
after long droughts, when the pits from 
which it is drawn have not been freed from 

7. Bay fait oft-times alters in tajle, as well 
as in other qualities , by long keeping. The 
fait of Peccais for example, which, when 
firfl made, is fo naufeous and bitter as 
to be unfit for domeflic ufes j by keeping, 
acquires a tafle that is more agreeable. For 
the bitter purging falts being very foluble in 
water, eafily diffolve by the moiflure of the 
air, and fink through the common fait in a 
liquid form, leaving it more pure, and free 

" Jufques a la derniere inondation du Rhone, qui fit 
" fondre dans ce lieu-la une fi grande quanrite de fel, il 
" y en avoic toujours eu de dix annees." Hijloire Phy- 
fique de la Met; Partie ii. pag. 35, 3 6. 

L 4 fro"i 

152 Of the different qualities of 
from its bitter tafte. Thefe calcarious falts' 
may alfo be frequently wafhed by rains 
from amongft bay fait, as it lies in heaps 
expofed to the weather. Alcaline falts may, 
after the fame manner, be difcharged from 
amongft common fait ; or when long ex- 
pofed to the air, may imbibe its volatile acid 
fpirit, and with it be converted into a neu- 
tral fait. And for thefe reafons, not only 
bay fait, but moft other kinds of common 
fait, become better and fitter for domeftic 
ufes, by being kept a confiderable time ex* 
pofed to the air in a dry place. 

CHAP. ir. 

Of the different qualities of white fait. 

WHITE fait, as well as bay fait, is 
commonly mixed with various im- 
purities, which it receives from the waters 
from which it is extracted ; and from thefe 
impurities, and the different methods ufed 
in its preparation, it is found to acquire very 
different properties. 

I. The grain oi white fait differs greatly^ 
according to the manner of its preparation, 
as hath before been related. The loaves of 
faltj or bafket fait, is of the fineft grain, be- 

Wh ite Salt. 153 

ing rather powder then cryftals of fait. Of 
the Britifli fea fait, that made at Lemington, 
and of the Britifli fountain fait, the fliivery 
fait, are of the largefl grain. But the cry- 
ftals of -the fait v/hich the Dutch make for 
curing proviiions, are much larger than thofe 
of any other kind of boiled fait. 

2. White fait alfo differs greatly in the 
hardnefs and Jirmncfi of its grain j fome 
kinds of it being of a foft, loofe, open grain, 
which readily crumbles between the fingers ; 
whilft other kinds are of a firm, hard, regu- 
lar grain, which is not fo eafily broken. 

3. It hath before been obferved, that 
the heterogeneous Juhjlances moil commonly 
mixed with bay fait, are clay, mud, and 
dirt 5 but thofe from which white fait is fel~ 
dom perfedtly free, are the calcarious earth 
called fcratch, and the falts of bittern j it is 
alfo frequently contaminated with the addi- 
tions before fpoken of, and with dirt, aflies, 
coal, foot, and other impurities : from all 
which it receives peculiar qualities, as will be 
more fully explained hereafter. 

4. Boiled falts diifer greatly as they are 
more or lefs durable i?i the open air. For 
violent boiling of the brine not only makes 
the fait of afmall irregular grain, as was be- 

1 54 Q/' t^^ different qualities of 

fore obferved, but alfo difpofes it more 
ilrongly to attradt the moifture of the air, 
and to run with it per deliquiiim. And the 
operators fay of fuch fait, that it is not well 
cleared from the frefli. Alcaline falts, and 
the other falts of bittern, as they greedily 
imbibe the aqueous moifture, difpofe the 
common fait, wherewith they arc mixed, to 
grow foft and relent in the open air, as hath 
before been obferved. It is a general obfer- 
vation, that the larger the grain of fait, (<:^- 
terls paribus) the more durable it is in the 
open air. And fait made up into loaves will 
remain drier than fait of the fame kind which 
hath its grains diftinited. 

5. The feveral kinds of boiled fait alfo 
differ ifi colour. That which is of the fmalleft 
grain, the pureft, and drieft, is commonly 
the whiteft. Moft of the fait made in Scot- 
land, is of a dirty grey colour, not being 
cleared from mud by clarifying the brine. 

6. White fait hath commonly no fmell-, 
but fometimes the corrupted blood ufed in 
clarifying it, or the unduous fubftances added 
to it give it one which is very difagreable. 

7. The feveral kinds of white fait are alfo 
found to differ greatly i?i tajie -, for fome 
kinds have a much more ll:iarp and pungent 


Whit e Salt. i55 

tafle than others. In general, that which is 
of a large grain, and made with a gentle 
heat, hath a iliarp, biting tafte ; whilfl: that 
which is made with hafly fires, and of a 
fmall grain, tailes commonly more flat, and 
foft. There are fome kinds of white fait in 
which a bitter tafte may plainly be difcovered ; 
as in fea fait boiled with hafty fires, and not 
drawn from the bittern at a proper time. 
The cat fait, which cryflalizes in marine 
bittern, hath alfo a bitter tafte, but is fliarp, 
and ftrong. Moreover, fait hath fometimes 
a very naufeous tafte from corrupted blood \ 
and other impurities mixed with it by igno- 
rant operators. 

8. White fait often undergoes confidera- 
hle alterations by keeping. The alcaline falts 
intermixed with it being converted into neu- 
trals by the aerial acid ; or elfe melted out 
of it together with the bitter and calcarious 
falts by the moifture of the air. The fcratch 
contained in it may alfo germinate with cal- 
carious falts. It is found by experience, 
that fea-falt prepared after the procefs before 

* Dr. Plot afTerts, that the blood ufed in clarifying 

. fait gives it an ill colour, as well as a bad favour. H'lji- 

cf Staffordjlnre^ Chap. ii. § 107. This is confirmed by 

Dr. Raftel, in his account of the method of preparing 

(alt at Droitwich, 


1^6 Of the different qualities of 
related % grows dryer for two or three days 
whilft it remains in the crebs ; during which 
time the leach brine drains out of it, and 
the moiilure alfo exhales from it by its heat. 
For fome time after it gains in weight j but 
afterwards grows dry, and, if not often ftirred, 
becomes rocky, adhering together in one 
folid mafs. 

9. White fait is alfo found to differ 
greatly in Jirength. That fait may be 
efteemed the ftrongefl which hath the moft 
brifk and pungent muriatic tafte, and which 
is found the fittefl for curing fifh, flefh, and 
other provifions, and will preferve them 
longefl in hot countries ; and will keep them 
fweet and good when applied in a fmaller 
quantity than is necelTary of other kinds of 
fait. Of the falts abovementioned, bay fait, 
and the Dutch refined fait, are the ftrongeft ; 
the fhivery fait made in Chefhire is next 
in ilrength j and after it, fome kinds of brine 
fait ; although a fait equally ftrong may be ' 
made of the Englifh rock fait or fea water. 
The EngUili icfined rock, and fea falts are 
of different degrees of ftrength, according to 
the art ufed in preparing them 3 fo that fome 
kinds of them are good ftrong fait, whilft 

f In Part ii. Chap. ii. 


White Salt. 157 

others are wholly unfit for preferving pro- 

CHAP. in. 

Of the ufes of fait as a feafoning to our food. 

SALT hath been ufed by mankind as a 
feafoning to their food, in all ages, and 
by all nations, except fome of the mofl bar- 
barous, who are deflitute of the neceffaries 
as well as the conveniencies of life. It pro- 
vokes the appetite, ftrengthens the ftomach, 
promotes the digeftion and concodlion of the 
aliment, refifts putrefadion, prevents unna- 
tural concretions of the humours, and is mofl 
friendly and agreeable to the human body, 
entering its compofitlon as a necelfary ingre- 
dient. No wonder therefore that the Laplan- 
ders % amongft whom the ufe of fait is un- 

' " Bread and fait are unknown ro moft of them (ti^e 
" Laplanders) they uiing for bread, dried fifh beaten to 
" powder : and for fair, the inner bark of pine trees 
" prepared after this manner, viz. They unbark the tal- 
" left of thofe trees, clpeci.illy that part which is next to 
" the ground, and take of it the inner bark, whofe fever.:! 
*' coats they pare afunder, and expofc them v-'eil 
" cleaned to the fun to dry: then they tear them into 
'' fmall parts, and put them into pretty big boxes, made 
*' of the outer b:?rk of tree?. Thcfe boxes they dig un- 
*' der ground, and cover them v^'iih fand, and fo lee thera 


15^ Of the iifes of Salt 

known, feem to difcover the want of it, iDy 
the exility of their bodies, and the weak- 
nefs of their conflitutions ; being much lefs 
robufl and ftrong than other northern nations, 
who enjoy this excellent gift of God. More- 
over its ufes extend to many other animals 
belides the human race ; black cattle and 
iheep take a pleafure in licking it, and by it 
arc preferved^from many difeafes "^ j they alfo 
thrive to admiration, and quickly grow 
fat in marfliy grounds that are frequently 
overflowed by the fea. And if we defcend 
tb the vegetable tribe, we lliall find that 
fait contributes greatly to frudify the earth ; 
and when properly ufed as a manure, affords 

" be macerated for a whole by their own heat. Then 
" they make upon thofe boxes a great fire of blocks 
" of trees, by which thofe inner rinds acquire under 
" ground, a red colour and a grateful fweetifli tafte, 
"^ ferving them for a conoimcnr, and fupplying the 
" place of fair." Ph. Tranf. N^ 102. p. 35. Ex- 
trad:ed from Johannis ShefFeri Lapponla. 

* " In Hungaria, Polonia, Ruflia, Tranfylvania, Bo- 
" ruffia, necnon Gr^ecia falis foffilis frufta animantibus 
" objiciantur, ut ejus ufus internam corruptionem 6c 
**^ morbos arceat." Fi&d.Yh&nm De fontib.falfis Ha- 
ienfibus^ iffc. cap. vii. 

'' Quin & pecudes armentaque & jumenta fale max- 
" ime foHcitantur ad paftum, rnulto larf lort ladle, mul- 
" toque gratiore eriam in cafeo ( ^oic. Lr, ; ■■ horculc vita 
'* humanior fine fale nequic degere," ^cc. P'in. ^/at, 
Hijl. Lib. xxxi. cap. vii. 

as a feajoning to our food, 159 

ample nourifhment to com and other vege- 
tables ; and renders kingdoms rich and fer- 
tile where it happens to abound in the 

As fait poflefTes thefe and many other ex- 
cellent qualities, it therefore defervedly ob- 
tains a conftant place at our tables, as a fea- 
fonlng to our food. 

In different countries, different kinds of 
fait are applied to this ufe, as beft fuits with 
the conveniency or inclinations of the inha- 
bitants. Many nations are wholly fupplied 
with fofiil fait ; fome for table ufe prefer 
bay fait, which indeed hath the advantage 
in the fharpnefs of its tafle ; but the mud 

* The Rev. Dr. Shaw obferves, that the foil in Bar- 
bary is generally impregnated wich common falc and ni- 
tre, and that the v/arers of moft of the rivers and lakes 
have there a falc tafte. And to this grand and inexhau- 
ftible fund of falts, he very judicioufly attributes the 
great fertility for which that country hath always been 
remarkable ; and ftiil continues to be fo without any 
other manuring, but the burning, in fome few places, of 
the ftubble. 

On the contrary, where this fait too much abounds, 
it kills all vegetables, and renders the earth unfruitful, as 
may be obferved in grounds that hive been too long 
overflowed with falc water. Many arguments n:)!gh[ be 
ufed to fhew that the barrennefs of leveral African and 
Arabian deferts, proceeds in a great meafur>.^, from coo 
great abundance of fait. 


i 60 Of the i/fes of Salt 

^nd dirt commonly mixed with it, and 
more efpecially with the French bay fait, 
render it lefs pleafmg to the fight. Several, 
therefore, who are curious in the choice of 
table fait, ufe the French cream of fait, or 
the blown lalt of the ifle of May. * 

Others, who would have a cleaner and 
whiter fait than the common bay fait, choofe 
the purcfl and largeft lumps of it, and re- 
duce them to powder. Others walh them, 
and dry them before the fire, or in the fun, 
before they powder them ; and are thus 
furniflied with an excellent fait for the table, 
which they call powder fait. 

But in mod countries, where boiled fait 
can eafily be had, the prefererxe is given to 
it for table ufe. And for this purpofe, that 
is mofl efleemed which is the cleaneft, and 
drieft, and whiteft, and of the finefl grain. 
Such is the Englilli bafket-falt ; although 
much of it is very weak, and of a fiat talle, 
being boiled with hafty fires. Other kinds 
of white fait, although commonly mixed 
with fcratch, and alcaline and calcarious falts, 
yet need not be rejedied for table ufe -, fince 
thofe impurities are taken in fuch fmall 
quantities that they can have very little effedt 
upon the human body j and their effefts will 
I in 

m a condiment or pickle. i6t 

m moft conftitutions, be falutary rather than 


Of the ufe of fait as a condiment or fickle, 

BESIDES the ufe of fait as a feafon- 
ing to our meat, it is alfo defervedly 
efteemed the moil; proper condiment or pickle 
for moll kinds of food which it is found 
neceiTary to preferve. 

In the choice of fait for a feafoning, re- 
gard may be had to the palate, or to conve- 
niency j but much greater care is necelTary 
in the choice of fait defigned for curing pro- 
vifions. Forfeveral kinds of fait are wholly 
improper for that purpofe j and feveral kinds 
of food require a ftronger or weaker fait, to 
be ufed in larger or fmaller quantities, either, 
firft, according to the different manner of 
preferving them ; or fecondly, according to 
the different nature and qualities of the fub- 
ftances preferved j or thirdly, according to 
the climate, place, or feafon of the year in 
which they are cured; or laflly, according to 
the ufes to which it is propofed to apply them. 
For iirft, thofe kinds of animal food 
which are falted, and afterwards dried either 
in the fun, or by kitchen fires, are often as 

M well 

562 Of the ufe of Salt 

well preferved with a weaker, as with a 
ftronger kind of fait j and fometimes even 
better, very ftrong fait being apt to make 
them too hard, and too fait, and not fo 
agreeable and wholefome. Thus fome of 
the beft kinds of hams are cured with com- 
mon white fait, to which a little faltpetre is 
added ^; and thus preferved they are found 
more foft and juicy, and not of fo fiery a tafle 
as thofe preferved with flrong bay fait. 
Dried meats may alfo be more eafily cured 
with a weak fait, than pickled meats. For 
the juices of animal fubflances being infpif- 
fated by the heat ufedin drying, cannot run 
into thofe inteRine motions which are the 
eaufe of putrefaction. The acid of wood 
or turf fmoke, to which thofe fubflances are 
expofed, may alfo contribute to preferve 
them. In the Wefl Indies they can fcarce 
cure beef with pickle ; but eafily preferve it 
by cutting it into thin flices and dipping 
them into fea water, and then drying them 
quickly in the funj to which they give the 
name of Jerked beef. Several kinds of white 
fifh are alfo eafily cured by drying them in 

* In Virginia they cure their hams with bay falc j and 
it is there a common practice to rub them with thearhcs 
of hickery wood, inftead of falc-petre, in order to give 
them a red colour. 

I the 

m a condiment y or pickle, 163 

the fun, either without fait, or with only ufing 
a very little. 

2. Some kinds of animal food are cured 
with much greater eafe than other kinds ; 
and thofe require the ftrongefl fait and the 
greateft quantity of it which are cured witli 
the greatefl difficulty. In Virginia, and other 
parts of North America, they can pickle 
beef with Leverpoole fait, fo as that it will 
bear exportation to Barbadoes, and others of 
the Caribbee iflands^ but cannot rightly 
cure pork, for exportation to the fame illands, 
without bay fait. Herrings and other kinds 
of lifli, which abound in a thin fubtile oil, 
are more difpofed to putrefa<5lion, and re- 
quire a ftronger fait to cure them, than cod 
and other white fifli, which are lefs juicy 
and undnous. The livers of mofi: animals, 
efpecially of fifh, are fo apt to corrupt that 
they can fcarce be preferved v/ith any fiilt. 
Such parts of animals as are compa6t and 
iirm are alfo more eafily preferved than fuch 
as are loofe and porous, which readily ad- 
mit the air, the grand caufe of putrefaction. 
And for this reafon veal and other fleili meats 
corrupt moft quickly, when their cellular 
membrane hath been blown up by the but- 
chers, which practice is therefore forbidden. 
M 2 Beef 

164 of the life of Salt 

Beef alio and other pickled meats are ob- 
ferved to taint fooneft nigh the large vefTelSc 
And the heads of moft animals (efpecially of 
cod and other fidies) being very porous, are 
with great difficulty cured with fait. In 
curing of animal food, regard ought alfo to 
be had to the cop>ditioii it was in, when 
flaughtered j for it can fcarce be well cured 
if tlie animal was heated by driving, or much 
bruifed before it was killed. 

3. It is found more difficult to cure ani- 
mal food in hot climates, or in very hot 
weather, than in places and feafons wherein 
the weather is more temperate j and the 
ftrongeft fait is required where provifions 
are preferved with the greatefl difficulty. In 
thofe countries which lie between the tro- 
picks, they feldom preferve the flefli of ani- 
mals except by faking and drying it in the 
manner before related ; becaufe when they 
attempt to pickle it, it commonly putriiies 
before the fait can have a due effe(fl: upon it. 
For the fame caufe, in temperate climates, 
the hot feafon of the year is not efleemed a 
proper time for faking proviHons, except 
only fuch kinds as cannot be had at other 
feafon?. It is therefore necelTary to ufe the 


as a condiment or fickle. 165 

ftrongeft fait in curing thofe fifh which are 
taken in fummer, or early in autumn -, altho' 
a weaker kind of fait might ferve particularly 
for white ii/h, if caught at a more tempe- 
rate feafon. The places in which thofe 
fifli are cured often make a flronger fait ne- 
cefTary j for it is much more difficult to cure 
them on fliip-board, efpecially in the hold 
(where there is a moift flagnating air^) than 
at land, where there are cool cellars and other 
proper conveniences. And not only great 
heat and moillure, but alfo intenfe cold 
makes the feafon unfavorable for lalting pro^ 
viiions ; for in hard frofty weather, the 
houfewives obferve that animal food will not 
take fait, it being fo hardened and its juices 
fo congealed by the cold that the fait cannot 
penetrate it, and is not dilTolved by it. 

Lastly, provifions muft be cured in a 
different manner, and with different kinds 
of fait, according to the ufes for which they 
are deligned. For example, beef, herrings, 
and many other kinds of flefh and fiili may 
be pickled very well for home confumption 

* On the banks of Newfoundland they fait vaft 
quantities of cod in the holds of fliips, without putting 
Jhern into cafks j and thele they call Mud fifh. 

M 3 with 

266 Of the life of Salt 

with any good kind of common white fait ^ 5 
and, if carefully falted with it only once about 
the month of Odlober, will keep good and 
fweet for the whole year in a cool cellar. 
But fiefh and fifh fo falted are not fit for fea 
provifions, and would not endure exporta- 
tion into very hot climates. Thofe there- 
fore, who are mofl exa6t in pickling beef 
for exportation, after the animals have been 
carefully flaughtered, between Michaelmas 
and Chriflmas, take their carcaifes as foon 

3 It hath been much difputed amongft the proprie- 
tors of the feveral kinds of Britifli fak-works, whirh 
kind of white fait was ficteft for preferving provifions. 
The proprietors of the Newcaftle filr- works aflcrr, that 
their fair is the bed for this ufe, as being moft approved of 
at the Vidtualling- office. Theownersof the Lemn}ingron 
works affirm, that their fait is the ftrongeft and of the 
largeft grain. Many again afTure us, that for ftrength 
and purity no kind of white fait comes up to the brine 
fait, cfpecially to that which is made at Droitwich. It 
may perhaps be more difficult than many imagine, to 
determine which of thefe opinions is bcft fupported by 
fads, fince all thefe kinds of fait differ greatly accorxiing 
as more or lefs care and fldll is ufed in their preparation. 
However, I fnall prefume to remark, that, in general, 
the Britifh white fait is weak and impure ; and though it 
may ferve to cure prcviiions after the manner and for 
the ufes here mentioned j yet, if ufed alone, will fcarce 
preferve them for long voyages into hot countries j and 
further, that either through the bad management or the 
ignorance of the operators, fait hath often been made 
as Vv'ell from brine as fea water, which hath been found 
vholly unfit for preferving provifions. 

as a cojidimenf^ or pickle, 167 

as cold, and cut them into proper pieces ; 
and after rubbing each piece carefully with 
good white falt+, lay them on heaps in a 

'^ The method here defcribed agrees pretty well with 
that which is pradtifed in Ireland in curing beef for na- 
val provifions, and for exportation into the American 
colonies. The v/hite fak there ufed is chiefly brine fair, 
or refined rock fait which they have from Leverpool. 
Bay fait they have chiefly from St. Ubes and other parts 
of Portugal ; many of their falters will not ufe French 
fair, (though much cheaper) becaufe of its dirtinefs • 
and in faking commonly ufe about equal quantities of 
white and bay fak. 

The white fait ufed at the Vidlualling- office in Lon- 
don, is altogether Newcaflle marine fait j with which 
they require certificates upon the oath of the vender, 
that the fak fold to them was made at Shields or other 
places nigh Newcaflle, and is, at leaft, three months old. 
The method there pradifed of faking flefli for the Bri- 
tifli navy, is related in the following manner, by the 
Rev. Dr. Hales Philof. exper. pag. 89, 

*' They firft; rub it with white fak only ; then put it 
'^' into brine for five days to drain the bloody part out, 
*' for it is the blood that is mofl: apt to putrify : then 
" they pack it in caflcs, flirewing white and bay fak be- 
** tween each laying : then fill the caflc up with pickle 
*' made of water and fak, boiled fo ftrong as to bear an 
*' egg : they put three pounds and an half of fak to a 
*' gallon of water. The proportion of fak, pickle in- 
" eluded, is, to an hundred weight of flefli, four gallons 
'* and a half of white, and one and a quarter of bay 
«' fait." 

The fame gentleman tried how far flefli might be 

cured by injedling a flirong brine into whole carcafles of 

animals by the Aorta. An ox being thus treated, " two 

^[ cafks of the flefli which was not faked with diy fak, 

M 4 cool 

1 68 ^f the ufe of Salt 

cool cellar, in a drab with a flielving bot- 
tom, where they remain for four or five 
days, 'till the blood hath drained out of the 
larger vefiels. They then take the pieces, 
and dry them with a cloth, and rub them 
for the fecond time with powdered bay fait. 
They are then fit to be put up in cafks, and 
much care is ufed in packing them clofe, 
and In ftrewing between them large lumps 
of bay fait, as they are put up. When the 
cafks are filled with beef, their heads are 
fitted in ; and all the vacuities are afterwards 
filled up with the ftrongeil brine that can 
be made, which is poured in by a hole in 
the head of the caflc. This hole is after- 
wards clofed up, and the calk is made fo 
tight, that none of the brine can leak out, 

" foon flunk ro a very great degree. — The flefli of two 
'' other cafks of the fame ox, which was faked with dry 
" Jak before it was packed in the cask, being examined 
" eighteen months after, and a piece of it boiled, it 
" was judged not fit for men to eat, as its juices were 
*' entirely eat up by the (alt, and it fell in pieces hke rot- 
" ten wood. The mutton of a flieep that was hunted im- 
*^' mediately before it was killed, being injedled in the 
** fame manner, and afterwards falted with dry fait, and 
*' kept full fix months, proved good and fweet, and not 
*' too fik when firft frefliened in water." The fame 
gentleman is of opinion, that;this method might be of 
great ufe in hot climates, where flefli cannot be pre- 
served by the common methods. 


as a condiment or pickle, 169 

and no air can gain admittance. It is found 
by experience, that beef cured in this man- 
ner will keep good and fvveet for years in 
the hotteft chmates. 

The Dutch, as hath before been ob- 
fervedj ufe no fait for curing provifions, be- 
iides their own refined falti\ With it they 
can preferve flefli and fifli of all kinds as 
well as with the ftrongefl: bay fait 5 and 
chufe to be at the expence of refining bay 
fait, rather than to defile their provifions 
with the dirt and other impurities, with 
which it commonly abounds. 

From the foregoing accounts it appears, 
that various kinds of fait are ufed for curing 
provifions > but the fait which may in gene- 
ral be efi:eemed the beft for that purpofe, 
as preferving animal food mofl effedlually, 
and for the longeft time, is that which is the 
(irongefi and pureji j and may be known by 
the following characters, viz. 

It is ufually concreted into large grains 
or cryftals, whifch are firm and hard, and 
•in refpedl to thofe of other kinds of common 
fait, the moft folid and ponderous ; it is not 
difpofed to grow foft or moifl: in a mode- 
rately dry air, to which it mufi: have been 
expofed a confiderable time ^ its colour is 


I/O Of the ufe of Salt &c. 

white, and fomewhat diaphanous ; it hath 
no fmell; its tafte is truly muriatic, and 
more fharp and pungent than that of other 
kinds of common fait -, being dilTolved in 
pure water it cafls up no fcum, and depofits 
no fediment ; being mixed with fyrup of 
violets diluted in water, it heightens its blue 
colour, and does not turn it either green or 
red 5 and, by the exadtefl chemical trials, 
difcovers no fcratch, no alcaline, bitter, or 
calcarious falts, nor any other impurities 
whatfoever intermixed with it. 
' The falts which approach nighefl to this 
degree of perfection are the beft kinds of bay 
fait, and the ftrong Dutch refined fait ; but 
moil of the fait now made for fale is very 
far from anfwering to thefe characfteriftics, 
as will more fully appear in the following 
parts of this performance. 


( 171 ) 


Art of making Bay Salt. 


In which ^ federal methods are propofed for 
making bay fait in England, and other 
parts of the Britijh dominions, 

IN the foregoing parts of this work, I 
have briefly related the various methods 
of preparing fait that now are in ufe, 
fo far as they are come to my knowledge ; 
and alfo treated of the qualities and ufes of 
the feveral kinds of common fait as a con- 
diment, and feafoning to our food. From 
which fhort narrative it appears, that the 
art of preparing fait is not brought to fuch 
perfedlion in the Britifh dominions, as in 
feveral other countries, the fait there pre- 
pared being unfit for preferving many kinds 
of provifions. It remains now to Ihew, that 
this want of ftrong fait of Britifh manufac- 
ture, proceeds not from any defed; of na- 

1 72 Tl)e art of making 

ture, but of art j and that if proper fkill 
and induftry be ufed in the Britifh domini- 
ons, and due encouragements be there given 
by the legiflature, fuch improvements may 
be made in this art, that not only Great Bri- 
tain, but Ireland alfo, and the Britifli colo- 
nies in America, may be fupplied with fait 
of their own manufad:ure, proper for curing 
all kinds of provifions, in quantity fufficient 
for all their occafions, in quality equal, if 
not fuperior, to any foreign fait now made, 
and at a moderate price. Thefe are truths 
which I hope will appear evident from the 
fadls and reafonings contained under the fol- 
lowing proportions. 


^he quantity cfivater which annually falls in 
rain^ Jmw^ and hail, is very different in 
different parts of Great Britain j there 
commonly falling ahnoft double the quantity 
on the wefer?! coafsy that falls on the ea/lern 
ccafts of that if and. 

According to the obfervations hitherto 
made, the depth of water which annually 
falls on the ground, fuppofing it all to Mag- 
nate thereon, would, at a medium, amount 


Bay Salt. 173 

at Townly in Lancafliire to forty-two in- 
ches and a half' : at Plymouth to thirty-one 
inches*: at Upminfler in EfTex to nineteen 
inches and a quarter ^ : at Widrington in 
Northumberland to twenty-one inches and 
a quarter "^ : at Edinburgh to twenty-two in- 
ches and a half 5. 

This great difference in the quantity of 
water which falls in different parts of this 
ifland is not (as the Rev. Mr. Derham ^ and 
others fuppofe) owing chiefly to the plain- 
nefs or hiilinefs of the different parts of the 
country, but to feveral other concurrent 
caufes, and more efpecially to the different 
qualities of winds in different places, and 
to the fituation which thofe feveral places 
have, with refpedt to feas, or tradts of dry- 

The winds, which blow mofl frequently 
in Great Britain, are the fouth, fouth-weft, 

' See Mr. Townlsy's Ohf. in the /Ms of the Royal 

' See Dr. Huxham in his treatife De aere ^ morb. 
epidem. Plym. and Medicul EJliys^ vol. v. arc. iii. 

5 See Mr. Derham's Mnuorokg. Ohf. in the Fh, 

•♦ Ph. Tranf Gray's Jb. vol. ii. pag. 4.5. 

* Medical Efpiys^ vol. v arc. iii. 

^ See his Fh-fico-Thcol. Book iii. chap. v. nore L. 
Alfo Fh. Tr.tst 2Uuid29j. 


1 74 T'he art of making 

and weft winds. Thefe are alfo the warmefl 
winds, raifing vaft quantities of clouds and 
vapours, which they drive before them from 
the great weftern ocean and Irifh fea. The 
greatefl part of thefe clouds and vapours 
falls upon the coafts from Land's-end to the 
north of Scotland. And hence Wales, Lan- 
cafhire, Cumberland, and other places fitu- 
ated on the weftern coaft, are watered with 
heavier fhowers than any other parts of the 
iiland. For (as Mr. Townly ^ formerly ob- 
ferved) the clouds and vapours driven from 
the fea feldom pafs to the oppofite fides of 
the ifle, but generally defcend in rains and 
other, watery meteors, before they have 
pafied thofe ridges of mountains which run 
along the middle of it. So that the fouth 
and fouth-weft winds are rainy winds in 
Lancaihire, and all other places on the wef- 
tern coafts, but dry winds on the eaftern 
coafts : whereas, on the contrary, the eaft- 
erly winds bring rain and fnow with them 
to the eaftern coafts, but are dry parching 
winds on the weftern coafts of the ille. And 
this rule takes place even in the narroweft 
parts of Great Britain, as in the counties of 
Lancafliire, and Cumberland on one lide, 

7 p,A. Tranf, N^ 2o8. pag. 53. 


Bay Salt. 175 

and Northumberland, Durham, and York- 
fliire on the other, where the land winds 
are the dryeft winds, and the fea winds the 
moft wet and n;oift ; which alfo holds true 
in moft other parts of the world. 

Now as the eafterly winds blow more 
feldom in Great Britain, than the fouth and 
fouth-wefl winds, and are alfo colder, and 
bring lefs moifture along with them j there- 
fore the quantity of rain falling on the call 
coafts is only about half as much as falls 
upon the wcfl coafls of the iiland, and the 
quantity of rain which falls in Kent, EfTex, 
Middlefex, Suffolk, and Norfolk, is proba- 
bly lefs than in any other parts of the king- 
dom. For thefe counties are the farthell 
diftant from the weflern ocean 5 and the 
eafterly winds are not in them very rainy, 
as they only blow over a fmall trad: of the 
German ocean. As to Plymouth, and the 
fouth coaft from the Land's-end to Dover, 
the fouth and fouth-weit Vvinds^ bring thi- 
ther the largeft quantity of vapours and 
rain ; and for reafons very obvious, the 
quantity of water which falls there, is lefs 
than on the weft coafts, and greater than 
on the eaft coafts of the kingdom. 

* Medical E{fays^ vol. v. arc, iii, 


176 I'he art of making 


'the quantity of rain li^hich falls in Lane a- 
Jhire, durijig the four hottefi tnonths of the 
yeary 'viz. May, June, July, and Augufl, 
doth not at a medium amount to more than 
a third part of the quantity of water, 
'which falls in rain, ficivs, and hail, dur- 
ing the whole year. 

Having purpofely made the calculation 
from Mr. Townly's obfervations ' ^ I find 
that the quantity of water which fell in 
Lancashire for fifteen years fuccefiively, in 
the months of May, June, July, and Auguft, 
was to the quantity falling in the other eight 
months of the year during that time, in pro- 
portion as 20525 : 41595. So that during 
thofe fifteen years there fell above twice the 
quantity of water in rain, fnow, and hail, 
in the eight colder months than there fell in 
the four hotteft months of thofe years. The 
fame will probably hold true in other parts 
of the kingdom ^. 

» See Ph. Tranf. N" 208, or Lowthorp'5 Jb. vol n. 
pag. 44.. 

* Ac Padua the rain which fell for fix years in the 
fummer quarter*, v^SiZ to the rain which tell in the other 

L E M» 

Bay Salt. 177 


^he water ^ which afcends in njapours from the 
fea, very greatly exceeds that which defcenda 
thereon in rain and other aqueous meteors : 
But the quantity of water y which ufually 
exhales from a giveti part of the ocean in 
a giveji time^ cannot with any exacinefs be 

From the foregoing obfervations it ap- 
pears, that the exhalations which fupply 
this iiland with rain, are brought chiefly 
from the fea, the winds which blow over 
land being generally dry winds, and the fea 
winds commonly bringing rain and vaoours. 

three quarters of thcfe years as 5825 to 16% . 828. So char, 
during thofe fix years, there fell in the fummer quarter.^ 
fomcwhat more thnn a quarter part of the rain which 
fell there in all thofe years. For 5.825 ; 17.475 : ; 
1:3. See Ph. rr. N° 421. 

' The firft part of this propofition holds true of the 
Tea in general j though ic n:iight prove f.ilfe, if applied to 
particular parts of ir. For as at dry !ar:d, fo alio at Tea, 
there are fome places where it rains almoft confianrly, 
and others where it rains feidom or never. For exam- 
ple; in that part of the Achntic ocean called the Rains, 
and in the Andes of Peru, ic rains aIn:ioil continually : 
whereas in Egypt, and in the plain country along the 
coafls of Peru, and in feveral parts of the Pacific ocean 
it rains very kldum^ and in fome of thefe places fcarce 

:Di Which 

J 78 7 be art of makhig 

Which rule, if extended to other countries, 
is found more generally true on large conti- 
nents than in iilands. The evaporations 
therefore ariiing from the fea mufl very 
much exceed the aqueous meteors which 
fall upon its furface (as Dr. Halley and 
others have demonfiratcd ;) for othervvife 
there v^ould not be a fufficient quantity of 
vapours raifed from the fea, not only to fup- 
plv it, but the dry land alfo, with rain and 
other watery meteors. 

But the experiments made by Dr. Hal- 
ley and others, with a view to determine 
the exadl quantity of vapours arifing from 
the fea, are very infufficient for that purpofe, 
being only calculated to fhew the great power 
of the fun's heat in raifing exhalations j al- 
though this power does not extend to any 
great depth of the ocean, but is exerted 
chiefly on the fuperficial waters, and, in 
thefe northern climates, only at certain fea- 
fons of the year. 

But there is another heat, whofe power 
hath been little confidercd, by means of 
which vaft quantities of vapours are conti- 
nually raifed, in winter, as well as in fum- 
mer, by night as well as by day, from the 
profoundefl parts of the ocean. And with- 

Bay Salt. 179 

out due regard had to the efFeds of this 
heat, it will not be eafy to account for thofe 
vapours, which fall in rain and fnow in the 
coldell: months of tJie year. Befides the 
fun's heat, the fubterraneous heat therefore 
very greatly promotes the exhalation of wa- 
tery vapours, efpecially from the deeper 
parts of the ocean, where this heat is very 

For all obferving failors agree, that on 
the main ocean, and particularly on the 
great weflern ocean, the air is always mild 
and temperate, and the furface of the wa- 
ter feels conflantly warm in the coldeft fea- 
fons of the year 3 fo that the failors are 
able to judge of their approach to land by 
obferving the water to grow colder^. And 
this great warmth of the ocean at its furface, 
which tempers the winter's cold, doubtlefs 
proceeds from hot fleams and vapours, which 
find a quick and free afcent from the pro- 
founder parts of the fea. For in thofe parts 
of it which are fliallow, as on the banks of 

* To the greater cold of the land than of the maia 
ocean in thefe northern climates in winter, may be ar« 
tributed thofe colds and catarihous fevers, which con* 
ftantly afFed failors after having palTed the weflern 
ocean, as foon as they arrive at land cither in Great Bri- 
tain or in North America during the winter fcafun. 

N 2 New- 

l8o T'he art of ?naking 

Newfoundland, the air is found colder, for 
want of thofe warm fleams and vapours, 
which cannot fo eafily and quickly afcend 
through the folid earth, as through water. 
And hence thofe banks are conftantly covered 
with thick foggs ; the warm vapours which 
are brought from the deeper parts of the 
ocean being continually condenfed by the 
colder air upon thofe Hiallow parts ; in the 
fame manner that the watery vapours aie 
continually condenfed into mifts and foggs 
upon the icy mountains of Greenland during 
the fiimmer feafon^. The fame coutry alfo 

5 " The temperamenr ot the air is not unhealrhfal ; 
" for, if you except the fcurvy and diftempers of the 
" breaft, they know noihing here of the many other dii- 
" eafes, with which other countries are plagued ; and 
" thefe pectoral infirmities are not fo much the effecT:s of 
*' the excefTive cold, asof tiie nafty foggifli weather,\vhich 
" this country is very mucli fubjecl toj which i 
*' impute to the vafl: quantities of ice that covers the 
" land, and drives in the lea. ';^. From the beginning of 
" April to the end of July is the fogigifh fealon, and 
" from that time the fogg d.iiiy decreafes. But as in 
" the fummer time they are troubled with the fogg, fb 
" in the winter feafon they arc likewifc plagued wich the 
" vapour called froft-fmoke j which when the cold is 
" exceffive, rifes out of the Ica^ as the fmoke out of a 
" " chimney, and is as thick as the thickeft milf, efpe- 
" cially in the bays where there is an opening in the 
*' ice. Tt is very remarkable that this froft, damp, or 
" fmoke, if you come riear it, will finge the very (kin 

I furniflies 

Bay Salt. i^x 

furnlfheth us with a notable inftance of the 
great power of the fubterraneal heat in railing 
vapours even in the coldeft feafons of the 
year. For on the coafls of Greenland, when 
the furface of the fea is all frozen into ice, if 
there chances to be an opening therein, the 
warm vapours, which before were pent up 
beneath it, arife fo copioufly, that being fud- 
denly condenfed by the cold they appear 
like fmoke arifing out of a chimney. This 
inward heat of the fea hath therefore no de- 
pendance upon the fun's heat, but is equal 
in winter and fummer ; or even greater in 
winter, efpecially where the furface of the 
fea is then covered v/ith ice ; and is fo con- 
/iderable, that in the coldeft feafons of the 
year it continually agitates the aqueous par- 
ticles, feparates them from each other, and 
converts them into an elaflic fluid. In this 
manner vafl; quantities of watery vapours 
are continually raifed from the profoundefl 

" of your face, and hands • but when you are in it 
" you find no fuch piercing or fmgeing fliarpne's, buc 
" warm and fofr, only ic leaves a whire froft upon 
*' your hair and cloaths." Mr, Egede, Nat. Hi/I. 
of G^'cenland. 

N. B. The fkin is probably (inged, as obferved by 
the author, by firft being relaxed by the warm watery- 
vapour, and then immediately frozen by the cold. 

N 3 . parts 


'itz ^f^ art of making 

parts of the ocean. So that in eftimating the 
evaporations from the fea, regard fhould be 
had to its inward heat, to its depth, and to 
the bulk of water which it contains, as well 
as to its furface and the caufes which a(5l 

' As to the fubterraneous heat hath there- 
fore a very remarkable efted: in railing va- 
pours from the fea, it may, together with 
the force of the air and wind?, be eileemed 
fuflicient to elevate the greattft part of thofe 
vapours, which in this climate fall in watery 
meteors during the winter feafon. That the 
air and winds lick up vafl qu-jntities of va- 
pours hath long been obferved, but this their 
cffeift may probably be hereafter more fully 
explained by ekdrical experiments 4. It is 
however certain, that the particles of dry 
compreffcd air very ftrongly attrad: the 
aqueous particles, and continually unite with 
them at the furface of the water, and from 
thence are continually driven away with 
them by the force of the winds. The 
winds alfo conliderably promote this opera- 
tion of the air by agitating the water into 
waves, and encreafing its furface (often to 
double what it is when fuffered to fubiide into 
* See Dr. Defngulier's Trcaufe on Ehnrichy. 

a plain) 

i J^ 

Bay Salt. 1B3 

a plain) thus making the contad: between 
the air and water more vigorous and brifk, 
and in a much greater number of points. 
And from thefe reafons, and fuch experi- 
ments as have been made, the beft judges 
have concluded, that at ieaft as much water 
is exhaled by the air and winds, as by 
the fun even in the hotteft feafons of the 
year 5. 

Now the afcent of vapours is retarded 
by the abfence of the heat of the fun, and 
of the fubterraneal heat, alfo by a moifl and 
light air faturated with vapours, not agitated 
by winds, but hanging without motion over 
the furface of the water ; by rain filling the 

s As Dr. Halley and Dr. Borehaave. From the latter of 
whom the follovving pailagc is exiratfled. " Tandem, 
*• non eft alia caufa, quie tantam copiam aqux de 
" terra in serem evehir, quam ventus ^ quod idem 
" eximius Halleius pulchre docuit, quod variis experi- 
^* mentis ad ftuporem ulque didici. Dum enim cylin- 
*' drum cupreum aqua plenum tempeftati procellofic 
*^ exponebam, mirabar quam incredibilis aquse copia 
*' parvo tempore difflarctur: quum ftatim poftquam 
*' ventus fiiebat, parum modo in eodem coeli calore 
«' exhalaret." Chemia Part. Jit. cap. De a'ere. 

" The furface of water is liked up fomewhat fafter by 
<' winds than it exhales by the heat of the fun, as is 
<' well know to thofe who have confidered thofe dry- 
« ing winds which blow fomecimes." Dr. Halley in 
Pb' "Tr. abr. by Lowthorp, vol. ii. p. no, 

N 4 air 

1^4 ^he art of making 

air v/itli moiilure, and beating down the 
aqueous particles in their afcent from the 
earth -, by frofts congeahng the furface of the 
waters and by other caufes on which it 
would be tedious here to infifl:. 

As therefore the caufes which promote or 
retard the afcent of marine vapours are very 
numerous, and feveralof them fubjed: to con- 
tinual variations, and the true effed: of others 
can fcarce be determined, as of the fubter- 
raneal heat j neither can the quantity of water 
on which it ads be difcovered ; for thefe rea- 
fons, it feems impoffible to eftimate with 
any exadnefs the quantity of vapours which 
ufually arife from a certain portion of the fea 
in a certain time. The experiments hitherto 
made lor that purpofe were generally made 
upon water fct in clofe rooms, or at leaft in 
fhady places, where the rain could give no 
interruption j but where alfo neither the fun 
nor air could have their due effeds upon it, 
and where it could not, as in the deeper 
parts of the ocean, be much affeded by fub- 
terraneous heat. The calculations therefore 
made from fuch experiments muft needs be 
extremely inaccurate j fo that little certain can 
be determined from them concerning the 
evaporations made from the fea, although 


Bay Salt. 185 

they may be of ufe in demon llrating the fol- 
lowing propofition which more nearly re- 
lates to our prefent purpufe. 


'The quantify of water which commonly ex- 
hales in Great Britain ft^m fiallow pondi 
during the four hottejl months of the year, 
greatly exceeds the quantity of rain which 
commonly falls on the fur face of tbofc ponds 
during the faid months. 

The ponds of the French fait marfhes 
may well be efteemed fhallow ponds, fuch 
as here fuppofed j and fo may all others, 
which do not exceed the depth of two feet. 
In fuch ponds the water is not much ad:ed 
upon by fubterraneal heat; and therefore it 
is only neceffary here to conlider the effects 
of the fun and air upon water contained in 
them during the four hotteft months of the 
year. And thefe effedts will be much the 
fame, whether the water be expofed to the 
fun and air in {hallow veffels or in fuch ponds 
as are here fuppofed. 

The accurate Kruquius obferved, that at 
Delft in Holland the quantity of water fal- 

l86 ^he art of making 

ling on the furface of the ground did, one 
year with another, amount to about thirty 
inches ; and that about the fame quantity 
exhaled again from water placed there in the 
open air, but in a calm and Ihady place. 
And it is not to be doubted but that double 
the quantity, or fixty inches depth of water, 
would have annually exhaled, had it been 
placed where the fun and wnids could have 
had their due effe<fts upon it. 

' Dr. Halley found by exadt experiments 
made at London, that water placed there in 
a clofe room, where neither the winds nor 
fun could a(ft upon it, exhaled only the 
depth of eight inches during the whole year. 
He obferves, that " when once the furface 
'* of the water is inverted with a fleece of 
" vapours, the vapour rifes afterwards in 
" much Icfs quantity. And that when the 
'^ air was flill from wind, much lefs was 
*' evaporated than when there blew a ftrong 
** gale, although the experiment was made 
" in a clofe room." And makes no doubt, 
" that, had the experiment been made where 
" the wind had come freely, it would have 
'^ carried away three times as much water 

* See his Exp. in the ?h, Tr. N^. 212. or Loxvthorp 
:hr. vol. :i. p. 3. 

" without 

Bay Salt. 187 

" without the affiftance of the fun, which 
" would perhaps have doubled it." 

So that, according to his calculations, about 
the depth of forty eight inches exhales at 
London, in the open air, from the furface of 
water during the whole year. 

From the fame experiments it appears, 
that the evaporations in May, June, July, 
and Auguft, which are nearly equal, are 
about three times as great as in the months 
of November, December, January, and 
February, which are likewife nearly equal. 
And having purpofely fummed up the eva- 
porations, which he has fet down as made 
in the four months of May, June, July, and 
Auguft, I find them to the evaporations of 
•the other eight months of year in the pro- 
portion of S^Kys to 77345. So that the 
evaporations made in the four hottefl months 
of the year, were more by a tenth part than 
thofe of ail the other eight months. 

Supposing therefore that equal quanti- 
ties of vapours exhale from fliallow ponds 
in the four hottefl months, and in the eight 
colder months of the year j and that a third 
part of the water, which annually falls in 
rain and other aqueous meteors, falls in the 
four hottefl months : Then if, according 


1 88 ^he art of making 

to Kruquius's obfervations in Holland, fixty 
inches of water exhales during the year in 
vapours, and thirty inches again fall in rain, 
thirty inches will exhale in the four hotted 
months, 'and only ten inches will fall; fo 
that an excefs of twenty inches of water will 
arife, more than will fall during thofe four 

If again we make ufe of Dr. Halley's 
eflimate, and fuppofe that forty eight inches 
of water annually arife in exhalations from 
the furface of ponds at London ; and if 
(agreeable to obfervations) we allow twenty 
one inches of water to fall there in meteors 
during the whole year ; then feventeen inches 
of water will there exhale from the furface of 
ponds more than is received into them in 
rains during the four hotteft months^. But 
in the moft rainy parts of England, where 
\^ or fourteen inches of water may be fup- 
pofed to fall during the four months above 
mentioned, then, if in that time twenty 
four inches of water fhould be found to ex- 
hale, only 24 — i4:=^or ten inches of water 
will in fuch parts exhale from ponds, more 
than defcends during the faid four months^ 

* For V — V" =30 — 10= 20. 

4 For =24 — 7;=:i7. 



Bay Salt.' 189 

But all thefe calculations of the evapora- 
tions from ponds during the four hotteft 
months are probably ihort of the true 
quantity. For it has been obferved in France, 
that in exceeding hot weather water expofed 
there to the fun and air, will lofe an inch 
of its depth in twenty four hours. And 
from experiments made by Dr. Halley it 
appears, that fea water of the l^ime tempe- 
rature with the air in the hotteft weather in 
England, placed in a clofe room, loft a fifth 
part of an inch in twenty four hours ; and no 
doubt, if agitated by the wind, would have 
loft atleaft triple that quantity, or three fifths 
of an inch, in the iiime fpace of time ~, 
and fliould the faid evaporation continue 
conftant during the four fummer months, it 
would in thattime amount to7 3-t inches, which 
is more than thrice the quantity allowed in 
the above calculations. 


In feveral parts of England large quantities 
of bay fait may be extraBed frcm fea wa- 
ter during the hotteft months of the year 3 
by receiving the fait -water into po?jdSj and 
fuffering its aqueous parts thence to exhale 


190 tT/'r art of niaJdng 

by the heat of the fun^ and the operation of 
the air and iciiids. 

For if infome of the warmefl and leaft rainy 
parts of England a pond, at a moderate com- 
putation, ufually lofcs feventeen inches depth 
of water in exhalations during the four hot- 
teft months, more than it receives from the 
heavens during the fame time ; then if a 
firm and tight pond be filled with fea water 
to the depth of iixteen inches in the begin- 
ning of May, all that water, together with 
the rains that fall into the pond, will be 
ufually thence exhaled by the end of Au- 
guft, and the bottom of the pond will re- 
main covered with a cruft of fait; as in funi- 
mer may be obferved on the fea (hore in hol- 
lows of rocks, where fmall quantities of fea 
water have been left bv the tide, or, as is 
more obfervable in the falina^ before de- 
fer ibed ', from which vaft quantities of fait 
are annually collected. 

The evaporation of fixteen inches depth 
of water by the fun and air, is here fup- 
pofed to take up four months : in rainy 
fummers it may require a longer time, or 
even may not be effected during the whole 

» Part ii. Chap. W. 



Bay Salt. 191 

fiimm^r. But it alio often happens in many 
parts of England, that not an inch depth of 
water falls in a whole fummer month, and 
the weather in fuch dry feafons being ufually 
very hot, half an inch depth of water may then 
be fuppofed to evaporate every day j fo that 
the whole evaporation of fixteen inches depth 
of fea water will, in fuch a dry feafon, be 
performed in thirty- two days. 

The following calculation may give fome 
idea of the quantity of fait, which may thus 
be extracted from ponds covered Vvith fea 
water to the depth of fixteen inches. A 
cubic inch of pure water weighs about 256 
grains j and if we fuppofe that the fea water 
on the coafls of England contains ~y part of 
fait, then each cubic inch of fea water will 
contain ^-j-z •=: 8 grains of fait ; and fix- 
teen cubic inches 16x8=128 grains. There 
would therefore remain after the evaporation 
of fixteen inches depth of water 128 grains of 
fait upon every inch fquare of the pond, 
and upon every yard fquare 21 lb. 9 oz. 
288pwts. averdupoize weight; and upon 
every flatute acre of fuch ponds 1045441b. 
or 1245 bufh. 641b. of bay fait*. The price 

* Bay fait now cofts at London, evclufive of ex-cifc. 
Four fliilliogs and four penc-e per bulhtl. 



192 T'he art of 7naking 

of which, if fold for a fliilling a bufliel, 
would be 62 1. 5 s. pd. fo that ground 
rightly prepared might thus be made to 
produce annually an excellent rich crop of 
fait, which would not require more labour 
and expence than is neceffary for crops of far 
lefs value. 

But as the above method of preparing 
bay fait from fea water, is tedious and fub- 
jed: to mifcarry by ruins, and the fait fo 
made could fcarce be colle(fted without mud 3, 
and the calcarious earth, and other grofs in- 
gredients of fea water woidd remain mixed 


^ Mr. Boyle found the fpecific gravity of a hard 
lump of fea fak to that of common wacer almoit as 
2: I. But the fpecific weight of an hard ]un,p of faj 
gem. is to that of water nearly a? -/j : i. If therefore 
(as before fuppofed) each fquare inch of the bortom cf 
the pond W2s covered with a cruit of fait weighing 
128 grains then the faid crull would only be a quarter of 
an inch in thicknefs. For 250, the number of grains in 
a cubic inch of water, being divided by 2, gives 128. So 
that if a cubic inch of water be divided into two equal 
parts by a plain parallel to its bafe, each of ihofc parts 
'will weigh 128. and the altitude ot each will behalf an 
inch. But the altitude or thicknefs of a cruft of fak up- 
on the fame bale, and alfo weighing 128. will only be 
^ of an inch j feeing that the fpccific weight of fak is 
double ro that of commotj water. But lo hin a cruft 
of fak could fcarce be feparated from the bottom of the 
pond, without a large proportion of mud and other im- 
purities adhering to it. 




Bay Salt. 195 

with it, it would not therefore be advifeable 
to make a trial of this method ; efpecially 
as the following may eafily be put in prac- 
tice, which is far more commodious, expe- 
ditious, and certain. 


hi fever al parts of England large quantities 
of bay fait ?nay very cGmmodioifly be ex- 
traBedfromfea water ^ after the fame man- 
ner that is praBifed in France^ and in other 
parts of Europe. 

The parts of England mofl: proper for 
this work are thofe which are the warmefl 
and leaft rainy, as on the coafts from Dover 
to Yarmouth : although the fame work will 
fucceed very well in other places'. For if 
fuch large quantities of bay fait can be pre- 
pared in France as are fufficient for the wliols 
annual confumption of that large kingdom, 
and of all thofe nations who purchafe it from 
thence, and that in fo fl^iort a time as one 
fortnight of good weather j why may not 
large quantities be prepared in the above- 
mentioned, and feveral other parts of Eng- 
land, during the whole fummer feafon ? If 

I Particularly on the coaft from Dover to LandVend. 
O fait 

1 94 ^he art of making 

fait can be extraded in France, even in the 
night time, why may it not in England du- 
ring the day ? If bay fait can be made in 
confiderable quantities, and to profit, in the 
fun pans of Hampfhire ^, why not in larger 
quantities, and to much greater profit, in 
fait marfhes, which are much more artful 
and commodious ? 

There are feveral parts of the Englifli 
coaft, which do not lie above two or three 
degrees farther north than the coalls of Bri- 
tany, where fuch vaft quantities of bay fait 
are made ; and particularly the coafts above 
pointed out, where this fait is chiefly wanted 
for curing fifli and naval provifions ; where 
the heat of the fun is not much lefs than on 
the coafts of Britany ; where the winds and 
air will alfo have the fame eifedl as in Brita- 
ny ', and where, in all probability, there is 
confiderably lefs rain to retard the operation, 
than on the French coafts. So that it is 
not likely that this work would proceed 
much flower in England than in France. 

But, that this may more plainly appear, 
let it be granted, that the heat of the fun is 
fo much greater in Britany than on the coafts 

» See the foregoing accounts of the method of making 
bay fait in France and Hampfhire. 


Bay Salt. i^S 

of Efl*ex and Suffolk, that water will exhale 
even twice as faft in the firft, as it does in 
the laft mentioned places, during the fum- 
mer months. Allowing even this fuppoli- 
tion, it will be no difficult matter to fliew, 
that fuch an inconveniency might be over- 
come ; and that, under fuch circumftanceSs 
as much fait might be prepared in an Eng- 
lifh fait marfli as in one in Britany, and 
with no great difference of expence. 

Supposing therefore, that from a furface 
of one yard fquare, as much water exhales 
in Britany, as from a furface of two fquare 
yards in England. And if we farther fup«* 
pofe two cylindrical veffels of equal capaci- 
ties, but fo formed, that the furface of the 
fluid in one, is double to the furface of the 
fluid in the other, and that thefe vellels, 
when filled with water, are placed, that with 
the larger furface, in England, and that with 
the fmaller furface, in Britany : then^ ac- 
cording to the firft fuppofition, equal quan- 
tities of water will exhale from thofe two 
veffels in equal times, and both veffels, as 
they contain the fame quantity of water, 
will become empty in the fame fpace of 
time. And if the water in both veflels be 
of an equal faltnefs, an equal quantity of 
O 2 fait 

ig6 'fir art of making 

fait will remain in each veffel, after all the 
water is exhaled. 

It is therefore very poffible to anfwer all 
the requilites in the following problem, viz. 
By a moderate heat of the fiin, and the 
force oj the airy from a gi^ven quantity of 
water to exhale a certain quantity givertj 
in a given time ; for this may be done 
by proportioning the furface of the water to 
the force of the fun and air, and to the quan- 
tity of water required to be exhaled in the 
time given. 

Should it then be required to make the 
fame quantity of bay lalt at a fait work in 
England, as is ufually inade at a fait work 
of the fame kind on the coafl of France ; 
that this may be done, it is neceffary that 
equal quantities of fca water (fuppofed at 
both places of an equal faltnefs) fhould be 
received into both works, and that the eva- 
poration fliould be equal in both. Which 
would be the cafe, if the water in the fait 
work in England be expofed to the fun and 
air with a greater furface than in the French 
work J fo that this greater extent of furface 
may compenfate for the lefs force of the fun's 
heat : or, in other words, fo that the whole 
furface of the two fait works may be in a 


Bay Salt. "197 

reciprocal proportion with the evaporations 
from equal portions of their furfaces. For 
example j if the evaporation from a certain 
part of the French fait work, be double to 
the evaporation from an equal part of the 
Englifli work, then muft the furface of the 
EngHfh work be double the furface of the 
French work. And fmce an equal quantity 
of flit water or brine is fuppofed to be con- 
tained in both w^orks, therefore the Englifli 
pits muft in fuch cafe have only half the 
depth of water in them, that is in the 
French pits. So that in the refer voir, where 
there is ten inches depth of water in the 
French work, there muft be only five inches 
depth in the Englifli work, and in the fhal- 
lower pits in the fame proportion. 

The foregoing calculations are made up- 
on a fuppofition, that it is dry weather, du- 
ring the whole time that the water is eva- 
porating ; but as in the fait marflics this 
bufinefs is frequently difturbed by rains, it 
is neceffary, in prad'ice, alfo to make an 
allowance for the water received from the 
atmofphere into the fait marfh during the 
evaporation ; and upon that account, to en- 
large the furface of the Englifli work yet 
confiderably farther. For fuppofing only 

O 3 the 

J 9$ ^he art of making 

the fame quantity of rain to fall into the 
Engliih, as into the French fait work , as 
the evaporation is fuppofed flower upon a 
certain part of the Englifh work than upon 
an equal part of the French work, it is ne- 
cefTary, that the water falling into the iirfl 
work be fpread over a larger furface, than 
that which falls into the latter, in order that 
in both it may be exhaled in equal times. 
But as the furface of the Engliih work is 
fuppofed larger than the furface of the French 
work, more rain may probably fall into it 
than into the French work ; fo that it may 
be necefTary to extend the furface ftill far- 
ther ; and fo to evaporate the excefs of wa- 
ter, which it receives from the atmofphere. 

How far it may be really necelTary to 
extend the Englifli work farther than a 
French work of the fame capacity, in order 
to make an equal quantity of fait in each of 
them, can only be afcertained by proper ex- 
periments. But all circumftances being duly 
confidered, we may reafonably conjedlure, 
that, in feveral parts of England, if a fait 
marlli was formed, whofe furface was only 
a iifth or a lixth part larger than that of a 
French fait marfli, as much fait, at lead, 
might be prepared in the Engliih marfh, as 


Bay Salt. 199 

in that of France. And if we confider the 
iituation of the French coaft, how it mull 
be watered with heavy rains from the weft- 
ern ocean, we cannot fuppofe that iefs wa« 
ter falls there in rain and other aqueous me- 
teors, than on the coaft about Plymouth, 
which at a medium is thirty-one inches in 
the year ; whereas on feveral of the warm- 
eft parts of the Englifli coafts there does 
not annually fall above twenty inches. So 
that during the fummer feafon more water 
will probably fall into the French fait marfli 
than into one of a fifth part larger furface, 
fituated on the coafts of Effex, Norfolk, or 

If therefore it fliould prove true in facfl, 
as in all probability it will, that as much 
fait may be extradcd from an Englifli fait 
marfli, as from one in France, when the 
furface of the former is one fifth larger than 
that of the latter : then, in order that both 
works may contain an equal quantity of 
brine 3, it will be neceflary, that in the re- 

' The following theorem may be of ufe in determi- 
ning the depths of the feveral ponds, fo that the two 
falc marilies may be made to contain equal quantities of 
brine, viz. 
As the furface of the broader pond in the EngUJh marjh^ 

is tg the depth of the narrotver pond in the French marfj ; 

O 4 fervoir 

200 ^ke art of making 

fervoir where the fait water is ten inches 
deep in France, it be eight inches one third 
in England i and the fait pits where the 
brine is one inch and an half deep in France, 
it muft be one inch and a quarter deep in 
England"^. And care lliould be taken to lay 
the bottoms of the feveral pits in fuch a 
manner, that the depth of the brine in them 
may anfwer to the above-mentioned pro- 

The Englilh fait marfli muft be made 
larger or fmaller as occaiion requires j fo 
that care be taken to obferve the above, or 

fo reciprocally the fur face of the narrcvcer^ is to the 

depth of the broader. 

Thus, if the furface of the French refervoir be a hun- 
dred yards fquare, ics furface will then contain 5760000 
fquare inches. And the Englifh refervoir 5760000 x 

Z— =: 6g 12000 fquare inches. Then as the French 

refervoir is ten inches deep, according to the above the- 
orem, 6912000: 10 :: 5760000: 8*. And the pro- 
dud: of the two extremes will be found equal to that of 
the two means, which give the folid contents of the 
French refervoir in cubic inches. 

+ Suppofing the French fait pits ten inches fquare, 
their furface will contain a hundred fquare inches j and 
the furface of the Englifh fait pits (being one fifth of an 
inch larger) 120 fquare inches: then, 120: i\:\ 100: 

1 J-- I i 

The fame proportion will hold good, if the furface of 
the French fait pics be fuppofed of any other magnitude. 


B A Y S A L T. 201 

fuch Other proportion in the dhnenfions of 
its feveral parts, as by experience fliall be 
found mofl proper. In general, it is necef- 
fary that the refervoir and bnne ponds be 
of a fufficient magnitude to furnifh the fait 
pits with a conftant fupply of the flrongeft 
brine, in the place of that which is continu- 
ally reduced to fait. 


Bciyfalt may be extrcMed in 'England from 
fea water in larger quantities, and with 
more certainty, than by the foregoing methody 
if care be taken to preferve the brine con- 
tained in the fait -pits from being diluted 
with rains, and to promote the ccaporation 
of the Water by feveral artificial 7neans, 
which may eafly be put in praSlice. 

The above related method is eafy and 
prad:icable 5 and we find one much lefs 
commodious fucceed to advantage on the 
coafls of Hampfhire, where there falls one 
third more rain than in feveral other parts 
of the Englifli coaft. But thofe who are 
defirous of preparing more fait than can be 
done by the foregoing methods, and would 
have their work lefs interrupted by rains, 


202 ^he art of making 

and would chufe to have their brine lie 
deeper in the fait pits, and to have the fait 
formed into large cryflals, may for thefe 
and other purpofes have recourfe to the 
following methods. 

First, it will be proper to make all 
the falts pits of the marfli, in one long row, 
extended from eafl to weft ^ and for each 
pit to make covers of thin boards, or rather 
of coarfe canvas, or fail-cloth, ftretched on 
frames of wood, and painted white. Thefe 
.covers muft all be fixed with hinges to 
ftrong pofts and beams on the north fide of 
the pits, fo that they may be let down and 
drawn up with cords and pulleys, or by fome 
other contrivance, fomewhat like draw- 
bridges. Thefe covers thus fixed may be 
let down over the pits like a fhed or pent- 
houfe, in rainy weather; and in dry weather 
may be ereded almoft to a perpendicular, but 
inclining a little towards the fouth ; fo as to 
form a wall with a fouth afped:. And thus 
may ferve a double ufe, as coverings for the 

* It will be alfo neceffary to make the bottoms of 
the fait pits of alabafter, or fome other ftrong cement 
that will not eafily break up j by which means the fait 
may be drawn white and pure, as in Spain and Portugal, 

and nor dirty and grey, as in the French marflies. 


Bx^Y Salt. 203 

pits in wet weather, and as reflectors of the 
fun's heat upon them in dry w^eather. For 
when they are let down they will prevent 
the rain from mingling with the flrong brine 
contained in the fait pits j and when they are 
drawn up in fun fhiny weather, they will 
ftrongly refledl the rays of the fun upon the 
brine contained in the pits, and thus greatly 
promote the evaporation of its aqueous parti- 
cles. The hinges on which the reflectors 
turn may be fixed about eight or ten inches 
from the ground. By which means, when 
the reflectors ftand upright, there will be an 
opening left beneath them, through which 
the air will continually flow in a briiTc cur- 
rent, and greatly encreafe the evaporation of 
the water. 

In order alfo that no diluted brine may 
flow into the fait pits during rains, it will 
be neceflary at fuch times to flop the nar- 
row winding channel leading to the pits, by 
a little fluice. This channel alfo mufl: be made 
very narrow, and every where covered over 
with boards. And there mufl not be a pond at 
the entrance of the fait pits, as in the French 
mar{h, but only a narrow covered trench, 
running parallel to the fide of the pits which 
is oppoiite to the refledors. And the pond, 


204 '^ke art of making 

which forms the entrance of the pits in the 
French fait marfh, muft in this be detached 
from them -, and inftead thereof muft be 
formed a fourth brine pond, communi- 
cating with the third by a long narrow 

If thefe contrivances fhould be reduced 
to pracflice in England, the fait will proba- 
bly cryftalize there much fafter than in the 
French fait marfhes. And the brine may be 
kept as deep and even deeper there than in 
the French fait pits. In which cafe the 
Englilh fait marfh will require fewer pits 
than in the method propofed in the foregoing 
propolition. And if a fliower or two of 
rain chances to fall, the operation will only 
be retarded while the rain continues ; whereas 
in the French open work, fuch a quantity 
of rain falling often puts a ftop to the work 
for two or three days, as all the frefh water 
that fell muft again be exhaled, before any 
fait can be formed. 

But in order to prevent the weaker brine 
from being diluted with rains ; and in order 
alfo to provide a fufficient quantity of brine 
which may always be ready to fupply the 
place of that which cryftalizes in the fait 
pits, it may be neceflary to dig in the earth 


Bay Salt. 205 

four dfterns adjoining to the brine pits above 
propofed, which may be made tight at the 
bottom and fides with brick and clay, into 
which the brine in the fait ponds may be 
admitted when the rainy weather comes on, 
fo that the brine of different degrees of 
flrength may run into feparate cifterns, and 
may again be pumped out of them into the 
feveral ponds from which it was drawn, as 
foon as the weather grows dry, and the frefh 
water, which fell into the pits, hath by 
proper drains been firfl difcharged out of 

As to the fait water in the refervoir, if it 
fliould not be found necelTary to preferve it 
from rains in cifterns j when fo much rain 
falls, as to make it freflier than fea water, 
it may be let out, and fea water admitted 
into its place. And in order to promote 
the evaporation, and to make the fait water 
in the refervoir fitter to fupply the firft brine 
pood with brine of a due ftrength, it may 
be proper, by means of a fmall fire engine, 
continually to force up the fait water in the 
refervoir as often as occafion requires, and 
by means of a diverger fitted to the engine to 
make it defcend again into the refci voir like 
a fliower of rain j by which means the eva- 
I poration 

20 6 ^he art of making 

poration of the watery vapours will be greatly 
promoted, after much the fame manner as is 
pradifed at feveral fait works in Germany 
where the brine is very weak. 

And thus by augmenting the force of the 
fun's heat, and of the air, and by promoting 
the evaporation of the watery vapours, and 
by preventing the brine from being diluted 
with rain, it is very probable, that during 
the fummer feafon double the quantity of 
fait might be prepared at an Engliih work 
with thefe contrivances, that is now ufually 
prepared at a French fait marfli of equal 


In fevei'al parts of E?igla72d large quantities of 
excelkvit bay fait tnay, with great eafe, be 
prepared frotn the natural brine of fait 
fprings^ and alfofrom rock fait diffohed in 
weak brine y or fea water. 

In Chefliire, where they have natural brine 
almoft fully faturated with fait, if they 
fl:iould think proper to extrad: bay fait from 
this brine, it may be pumped dire(flly into fait 
pits (without any previous preparation) there 
to be wrought with refledors, as defcribed 


Bay Salt. 207 

under the foregoing propofition. Only, if 
there be any ochre or mud mixed with the 
brine, it may be proper to draw it firft into 
covered refervoirs or cifterns, there to ftand 
till thefe impurities are fubfided, and from 
thence to let it out into the fait pits as occafion 
may require. 

But if, as it commonly happens, the brine 
be not fully faturated with fait, then it may 
be expofed to the fun and air in brine 
ponds with reflecftors fitted to them until it 
be reduced to a faturated brine, after which 
it may be received into the fait pits. Or elfe 
the weak brine may be fully faturated with 
rock fait, where that can be had cheap, or 
even with white fait, if due encouragement 
be given by the legillature. Or where there 
is plenty of rock fait and no brine, frefh 
water, or fea water (if it can be convenient- 
ly had) may be faturated with it, and reduced 
to bay fait in fait pits with reflectors as before 

Thus large quantities of bay fait may be 
made from natural brine at one operation, 
as is pradlifed at the ifle of May and in feve- 
ral parts of the Weft Indies. Of the quan- 
tities which can thus be extra<5led feme 


20 8 ^hc art of making 

conjeftures may be made from the following 

Suppose a fait pit fixtecn feet fquare. A 
work confilling of eighteen pits of the fame 
iize, placed all in a row, will be ninety five 
yards long, and will be fomewhat larger than 
the flit pits of the French marfli before de- 
cribed. The area of each of thefe pits will 
be two hundred and fifty fix fquare feet, 
and if they are covered a quarter of a 
foot deep with brine, then each pit will 
contain fixty four cubic feet of brine. But 
from ' Dr. Baynard's experiments, a cubic 
foot of common water weighs exadly feven- 
ty fix pounds troy. Therefore fixty four 
cubic feet weighs 64x76^:4864 pounds 
troy. Suppoiing therefore each pound, or 
twelve ounces, of brine to contain three 
ounces and an half of fait, then 4864 pounds 
of brine will contain 17024 ounces or 1064 
pounds averdupois of fait, and eighteen pits 
of the fame dimeniions 191 52 pounds,which 
is exad:ly 228 bufliels of fait, each weighing 
eighty four pounds av^-dupois. 

But as a pound troy, or twelve ounces, of 
water, will diflblve more fait than three 
ounces and an half; if therefore the pits be 

* See his Exp. made at Oxford ; In the Ph. Tr. 


Bay Salt. 209 

filled to the depth of three inches with fully 
faturated brine, more fait will be contained 
in them than here fuppofed. If it therefore 
be granted, as many affirm, that a gallon, 
ale meafure, of the ftrongeft Chefhire brine, 
which is almoft fully faturated, holds three 
pounds averdupois of fait (which is very 
nigh a pound of fait to three pounds of 
water) the 7059 -^V gallons of fully faturated 
brine, fuppofed as before to be contained in 
the eighteen fait pits, will hold fomewhat 
more than 21 177 pounds, or two hundred 
and fifty two bulhels nine pounds of fait. 

In order to eftimate the time required to 
prepare the above quantity of fait, let it be 
fuppofed (as with great reafon it may) that 
in dry fummer weather, half an inch depth 
of water will, one day with another, exhale 
from the fait pits when wrought with re- 
flectors. Then three inches depth, the 
quantity of water contained in the brine, will 
be exhaled in fix days; fo that at the 
end of fix days all the fait, contained 
in the brine, will remain dry at the bottom 
of the pits ; which, according to the firfl 
fuppofition, is two hundred and twenty eight 
bufiiels of bay fait J and, according to the 
fecond, fomewhat more than two hundred 
Mty two bufliels. And if we divide thofs 

P quan. 

2io ^he art of making 

quantities by fi.:, the number of days inwhich 
all the water Vz exhaled, we fliall find that, 
according to the firfl fuppofition, thirty eight 
bufhels, and, according to the fecond, fome- 
what more than forty two bufliels of bay fait 
may be daily prepared in dry fummer wea- 
ther, in a work of the above dimenlions. 

The fame calculations alfo fhew the quan- 
tity of fait, which may be prepared from 
fea-water in a fait marfh, where the pits 
are of the dimenfions above fuppofed ; 
for in both cafes the fait pits mull be 
kept conftantly filled with a fully fatu- 
rated brine. But if only half the quan- 
tity here fuppofed, viz. twenty one bulhels, 
or 1764 pounds of fait, can be made every 
dry fummer day in a fait marfli of the above 
dimenfions, it is as much as is commonly 
mad^: every day from brine in a faltern whofe 
boy/icr contains eight hundred gallons. 


B^y Jcilt may be prepared in 'Eiigland by the 
foregoing methods at a very moderate ex- 
fence J equal in goodnefs to the bejl foreign 
bay fait, and in quantity fufficient for 
the confumption of all the Britifi domi-- 


Say Salt. 2h 

If in the firft place, we compare the 
French fait marfli with the Englifh faltern 
for boiling white fait, we fhall find the ex- 
pence of making the former much lefs than 
that of making the latter ; in which the ex- 
pence of boiling-houfes, hot-houfes, fur- 
naces, fait pans, &c. is very confiderable j 
and which alfo frequently require large fums 
to be laid out on them to keep them in re- 
pair; whereas the French marfli requires 
very little repairs. Befides, the expence of 
coals or other fewel is very great in the En- 
glifh faltern, which is all faved in the French 
bay fait work ; and the expence of labour 
will be more in proportion to the quantity of 
the fait made in the Englifli white fait work 
than in the French fait marfli. And for 
thefe reafons j though the French bay fait is 
better than the Englifli boiled fait, yet it 
can be made for feven or eight fhiUings a 
tun, which is little more than one third of 
the price for which white fait can be made 
in the moil commodious parts of Great 

If again we compare the French fait 
marfh with the Englifli rr»arfh, as propofed 
under Prop, the fecond, we fhall find that 
where the fituation is equally convenient, 

P 2 the 

212 ^hc art of making 

difFerence of the expence in making them 
will be very inconfiderable. For as the partiti- 
ons between the fait pits, and the trench and 
lluice which admit the fea water, and the walls 
between the ponds, are themofl expenfive parts 
of the work j if therefore the Englifh work 
be one fifth part more in furface than the 
French work, it will not require above 
one tenth part more expence to make it, 
than to make the other. And this fmall 
difference in the prime coft of the two 
works, will oceafion but a very trifling diffe- 
rence in the expence of making fait in them ; 
efpecially as the works, when finiflied, will 
require little repairs for twenty or thirty 

The expence of the Englifli fait marfh 
will indeed be confiderably increafed by the 
additional contrivances propofed under the 
third Prop. The mofl expenfive ofthefe 
will be the refledors, which I am in- 
formed by a good judge, if made of flrong 
fail cloth ftretched on frames, and painted 
white, and properly fixed to pofts, fo as to 
cover eighteen pits of fixteen feet fquare, 
might probably cofl 50 /. or at the moff 60/. 
And fliould all the other contrivances cofl 
60/. more, or even double that fum^ this 


Bay Salt. 2ij 

additional expence would be very quickly 
accounted for in the profit of the work, as 
it is probable that double the quantity of fait 
might be made with thefe contrivances, that 
could be made without them. And the ad- 
ditional labour, which thefe contrivances 
would occafion, would make very little en- 
creafe of expence, as it would all be per- 
formed when no fait is drawn, and confe- 
quently when the labourers have little elfe 
to do. 

As to the work propofed under Prop. IV. 
for making bay fait from natural brine ; 
twice as much fait might be prepared in it 
in one day (according to the foregoing cal- 
culations) as is ufually made in a Chefhire 
faltern, whofe pan contains eight hundred 
gallons. Although the faltern would re- 
quire much more money to ere<5l it, and to 
keep it in repair, befides the expence of coals ; 
which is the heavieft article, cofting of- 
times above two thirds of the value of all the 
fait prepared with them. 

All thefe things therefore confidered, it 
may with reafon be prefumed that bay fait 
may be made in feveral parts of Great 
Britain, nearly as cheap as it is now 
made in France. And as the French and 

P 3 other 

^14 ^^ ^^^ of making 

other foreign fait mufl: be charged with a 
confidcrable freight when brought to the 
Britifh market, it is very probable that bay 
fait made in great Britain might be afforded 
cheaper there than French or any other foreign 
fait; efpecially as thereis i^. i 7 f/. paid more 
in duties for every half hundred weight of 
foreign fait, than for the fame quantity of 
Britifh fait confumed in England ' ; which 
ought to be conddered as a bounty to the 
Britifh manufac^turer of bay fait. More- 
over, the law now allows three bufliels duty 
free, for every wey (or forty bufhels) of 
Britifli fait carried coaft-wifej which allow- 
ance will not only make up for the wafte in 
carriage, but will alfo pay the expence 

' By the laws as now eftablifhed, white fait and other 
fair of Britifh manufa<5lure confumed in England pays a 
duty of 3 J. \.d. per bufhe!, weighing fifty fix pound. 

But bay fait, and other foreign fait there confumed, 
pays a duty of 6 s. bV/. per bufhel, weighing eighty 
four pound. So that fifty fix pounds of foreign fait pays 
4 J. 5 J. in duty ; from which 35. ^d. being deduifled, 
there remains \ s. \^d. which is paid for fifty iix pound 
of foreign fait more than for the fame quantity of Britifh 
fait confumed in England. In both cafes an allowance 
is made for prompt payment. In Scotland the excife 
upon Rririfli fait as well as foreign fak there confumed, 
is only half of [hat paid in England, 

And all fait applied to curing fuch fifli as is exported to 
foreign markets, is in both parts of the united kingdom 
free from duty. 

^ of 

Bay Salt. 215 

of carrying the fait to market, to moft parts 
of England. The laws therefore, as they 
now fland, are extremely favourable to the 
Britlfh manufafturers of bay fait, who, to- 
gether with the public, would, in all probabi- 
lity reap great advantage by making fait 
works, fuch as before propofed. And fuch 
numbers of thefe works might be made at 
proper places along the Britifh coafts, and 
nigh brine pits where fuel is fcarce, as would 
afford bay fait enough for all the occafions of 
Great Britain 3 and might even furnifh an. 
article for exportation in thofe fhips which 
are fent from thence empty to Denmark, 
Norway, and into the Baltick, for hemp, flax, 
iron, timber, and other commodities of thofe 

It remains now to (liew, that bay fait, 
thus made in Great Britain, will, anfwer all 
the purpofes of foreign bay fait, and will be 
equally good for curing fifli and flefli, and 
for all other culinary ufes. 

As to the fea fait, no one will call this 
in queftion, lince it is made from the fame 
water as foreign marine bay fait, and the 
method propofed for making it appears to be 
at leaft as good as that which is pradtifed by 
foreigners. And it hath already been found 

P 4 by 

2i6 ^'be art of making 

by experience, that bay fait made in Hamp* 
fhire is not inferior to foreign bay fait for the 
abovementioned ufes. Aad where natural 
brine is fufficiently pure, as at Droitwich, 
there is no doubt but that an excellent bay fait 
might be made from it at one operation, as 
is pravftifed in the ifle of May, and in other 
hot countries. But if there be much calca- 
rious earth, or other earthy impurities mixed 
with the brine, as in Chefhire j fuch brine 
will afford a better fait if it is only of a mo- 
derate ftrength, fo that it may remain a con- 
fiderable time in brine ponds, there to mel- 
low, and to heighten into a fully faturated 
brine, and to depoiite its earthy impurities, 
which would be very pre;udicial to the fait 
if mixed with it, as will be more fully ex- 
plained hereafter. 


In federal of the Britifi colonies in America -^ 
bay fait mighty with little expence and trou- 
ble^ be prepared from feaivaterjn quantities 
[uficient to fiipply the American ffierieSy 
and all the other occa]ior{s of thofe colonies, 
fo as to become a confiderahle branch oj 
their trade. 


Bay Salt. 217 

Jt feems a truth deferving the confidera- 
tion of every friend to Great Britain, that its 
colonies in America might be made capable 
of furnifhing it with almofl all kinds of na- 
tural commodities, which it wants of foreign 
produdlion ; as wine, oil, fpices, tea, filk, 
hemp, iron, and other metals. Salt is alfo 
a commodity, which thofe colonies might be 
made to yield in great abundance j and is fo 
much wanted for their own confumption, 
and fo neceflary for the fupport of thtir 
iifheries, that it feems ftrange that its manu- 
fadture fhould have been there fo long neg- 
lected J efpecially as it might be made in moft 
of thofe colonies at a very fmall expence. For 
all the fea coafts of Georgia, Carolina, and 
Virginia, and the ifles of Bermudas, lie be- 
tween 3 1 and 3 8 degrees of latitude ; fo 
that their moft northern parts are eight de- 
grees nearer the line, than thofe coafts 
where the greateft part of the French fait is 
made. The grapes, which in France are not 
ripe till September, in Carolina are ripe in 
June, or the beginning of July. And in all 
thofe colonies the heats in fummer are more 
exceflive than in any part of the bay of 
Bifcay, and the draughts oftimes very 
diftreffing. So that there is no danger of 


2 1 8 '^he art of making 

wanting either fun or fair weather for making 
fait on all that vaft extent of coaft ; and even 
much farther northwards, as in New York, 
New Jerfey, and New England. In fuch 
parts therefore of thefe coafts as have a con- 
venient iituation, marine bay fait might be 
made with great eafe, and in very great abun- 
dance, and probably at as cheap a rate as in 
any other part of the world ^ fo that thofe 
colonies might be fupplied with fait of their 
own manufacture, at a much cheaper price, 
than they have it from the Cape de Verd 
ifles, and Salt-Tortuga j and would never 
more be put to the neceffity of bringing it 
from Sardinia and Portugal, as they now are 
in this time of war. For it is now found 
too hazardous an undertaking to go to the 
ifle of May, or Tortuga, to make fait, as 
fhips lying fo long in open roads are too 
much expofed to the enemy. And in times 
of peace the length of the voyage, the dan- 
ger of the feas in open roads, the expence of 
making and fhipping the fait, and the un- 
certainty of getting a loading, mufl make 
the fait from thofe iflands come much dearer 
to the Britifh colonies, than that of their own 
manufad:ure ^. 
* In times of peace bay fait is fold in bijlk in the Bri- 
1 As 

Bay Salt. 219 

As to Jamaica and the Caribbee iflands, 
which He between the tropics, the heat of 
the fun is there fo intenfe, and the weather 
fo fettled during the greateft part of the year, 
that thofe colonies might, with a very little 
trouble and expence, be fupplied with ma- 
rine bay fait of their own manufacture. 

If therefore in future times, the Britifh 
dominions, either in Europe or America 
/hould want bay fait of their own manu- 
fadure, fit and fufficient for all their occa- 
iions, and at as a cheap or even a cheaper 
rate than they now have it from foreign 
markets, it may be concluded that the fear- 
city proceeds, either from a want of induftry 
in the Britifh fubjedls, or elfe, for want of 
proper encouragements from their legifla- 

tifli colonies in North America, at a medium for about 
15^. per bulliel (and cannot well be afforded for lefs, as I 
am afiured by gentlemen of experience) and now in time 
of war above double that fum is paid for it, and it can 
fcarce be had at any price,- although it might be made 
in thofe colonies for 4 d. per bulhel in times of war, as 
well ^^ in times of peace. 


( 220 ) 

The A R T iSf preparing 



In which fome methods are propofed for pre- 
partJig white fait ft for preferving pro- 

ALTHOUGH it may be prefumed, 
that if the rules before given be re- 
duced into pra(5lice, the fubjecfls of thefe 
kingdoms may be fupplied with excellent 
bay fait of Britifli manufacture, fit and fuf- 
ficient for their occafions ; yet neverthelefs, 
I am defirous of propofing feveral improve- 
ments that may alfo be made in our methods 
of preparing white fait j which, if brought 
into ufe, may probably be of advantage not 
only to private undertakers, but alfo to the 
public. From what hath before been ob- 
ferved, it appears, that two very different 
kinds of white fait arc required 5 the one for 


'The art of prepari?ig &c, 221 
the ufe of the table, and the other as a con- 
diment for provifions. Its whitenefs, dry- 
nefs, and the fmaUnefs of its grain, are the 
properties which chiefly recommend the firft 
kind ; and its great ftrength and purity, the 
latter. It is this flrong and pure kind of 
white fait which is wanted in the Britifh 
dominions j and it is therefore my principal 
defign here to confider how this defed: may 
be fupplied ; although inftrudlions will at 
the fame time be given how to prepare table 
fait, not only better in quality, but alfo at a 
lefs expence than it is now prepared by the 
common methods. 


In the common procejjesfor making 'white fait, 
the fait is deprived of a confider able part of 
its acidfpirit by the violent boiling ufed in 
its preparation. 

The Rev. Dr. Hales, to whom the world 
is indebted for many excellent difcoveries, 
in the method which he hath publifhed of 
making fait water fweet and potable, hath 
given us the following experiments. 

' He diftilled fea water to a drinefs in 
glafs vefTels, dividing the water as it came 

/ ScehiS Pbilof. fxpcr. pag. 12, i; 14.. 


222 The art of pre parting 

over into nine different portions. He ob- 
ferved that the firfh portion, which arofe 
till the water began to boil, was pretty well 
tailed ; but the feven portions which came 
next over while the fea water in the retort 
was boiling, had all of them a flat, unfalt, 
naufeous, dry, aduft tafte. The ninth por- 
tion, which came over laft, till the fait in 
the retort was diftilled to a drinefs, was 
more harfh and difagreeable than any of the 
reft, tafting more of a kind of fpirit of fait j 
but none of them had any tafte like bitter- 
nefs or bitumen. Half a fpoonful of each 
of thefe nine portions of diftilled water be- 
ing put into feparate glafles, to each glafs 
was added two drops of a folation of pure 
filver made in aqua fortis, and diluted with 
fpring water. This folution immediately 
caufed white clouds in the clear diftilled 
water, which were leaft In the firfl portion, 
and nearly the fame in all the others, except 
in the laft, which had whiter and thicker 
clouds than any of the reft. And thefe 
white clouds plainly difcovered the diftilled 
water to be impregnated with fpirit of fait, 
by means of which the filver diflblved in 
the aqua fortis was precipitated. 


White Salt. 223 

= By other experiments, the fame learned 
gentleman found that the fpirit of fait arifes 
in greater quantities in proportion as the di- 
filiation is carried on farther 3. He alfo 
obferved, that when fea water was diftilled 
before it had corrupted, a third part of the 
water, which firft came over, had no very 
confiderable quantity of fpirit of fait mixed 
with it, but might be ufed inflead of frefh 
water. For though when firft diftilled, it 
gave white clouds with the folution of 111- 
verj yet after Handing in flafks for three 
months, it no longer gave any white clouds, 
nor other marks of acidity. But the two < 

remaining thirds of the water, which were i 

laft drawn off, after (landing three months, 
ftill continued to tafte tart and rough, and | 

gave manifeft clouds with the before-men- 
tioned folution. 

"^ He alfo difcovered that fea water after \ 

putrefadlion, might be diftilled with a boil- 

* Philof. exper. pag. 38. 

* The fame work, pag. 39, 40. 

■♦ It feems reafonable to believe, that when fea water 
is evaporated by a boiling hear, it emits the acid fumes 
of fak fooner and in larger quantities when frefh than 
after a putrefadion ; becaule while it is frelh and 
retains its vifcofuy, it requires a ftronger heat to difen- 
tangle its aqueous pares, and to reduce them into va- 
pours. And by this ftronger heat the acid fpirit is alfo 


224 5^^ ^^^ of preparing 

ing heat, till four fifths of it was come over 
before any confiderable quantity of the fpi- 
rit of fait would arife. But when the diftil- 
lation was continued until the fait in the re- 
tort remained dry ; that fifth portion of the 
water which lafl: arofc, was fo ftrongly im- 
pregnated with fpirit of fait, that it tafted 
plainly acid, and not only precipitated filver 
from the before-mentioned folution, but 
alfo gave greater marks of acidity by turning 
fyrup of violets red j which feveral other 
portions of diflilled fea water would not do, 
although they were fufficiently impregnated 
with the faline fpirit, to give white clouds 
with the folution of filver, as before related. 

5 The excellent Mr. Boyle aflures us, that 
when he diftilled fea water in a glafs head 
and body with a moderate heat, till a confi- 

feparated from the fair, and raifed when abouc a third 
part of the water is evaporated j but Vv'hcn, by putre- 
fa<flion, the water hath loft its vifcous quality, it boils, 
and this off in vapours with a lefs degree of heat i there- 
fore no acid fpirit is raifed till four fifths of the fea wa- 
ter is exhaled; (fee Dr. Hales Fh. exp. pag. 31.) but 
then, the water remaining, being greatly loaden with 
fait, and thereby made thick and ponderous, it con- 
tradts fuch an inrenfe heat in boiling, as is fufficient to 
feparate a confiderable quantity of acid fpirit from the 
fait, and to raife it along with the watery vapours. 

* See his Phil, werks abridged by Dr. Shaw, vol. iii. 
pag. 220. 


White Salt. 22^ 

derable portion of it was drawn over '3 he 
could not find that this v/ater, either by its 
tafte, or a more chemical examination con- 
tained any thing of fait in it j although it is 
well known, that he fir ft applied the above- 
mentioned folution in trials of this kind, and 
doubtlefs made ufe of it upon this occalion. 
Thefe his experiments do no ways difagree 
with thofe of the Rev. Dr. Hales before 
related ; for had Mr. Boyle applied a more 
violent heat, he would doubtlefs have found 
the diftilled water impregnated with the acid 
fumes of fait, as in Dr. Hales's experiments. 
And that fca water, when diftilled in 
large alembics, after the common method, 
with quick fires, doth part with a conliderable 
quantity of acid fpirit, was long ago known 
to Mr. I lauton ^ ; who in the method which 
he publiilied of making fait water fweet, 
very judicioufly dire(fts a certain earthy fub- 
ftance to be mixed with the diftilled water, 
and gently to fubfide therein j in order, as 
he fays, " to blunt the points of the volatile 
'' fpirits of the fait, and to fheath them, 
*' and take away the force of their maliga 
« fliarpnefs". 

^ Ph. Tranf, nb. vol. ii. pag. 277. 

Q^ .. And 

226 573^ art of preparing 

And that the volatile acid of common fait 
may be eafily feparated from its fixed alcaline 
principle, appears from an expermient of the 
illuftrious Mr. Boyle, who by along and arti- 
ficial digeftion of this fait, fo feparated thofe 
its two principles 5 that when this digefted 
fait was placed in a gentle fand heat without 
any addition, the fpirit arofe from it, pure, 
leaving the phlegm behind in the retort. 
Chemifts have alfo taken notice, that com- 
mon fait by being fufed in a crucible acquires 
an alcaline quality, a large quantity of its 
acid fpirit being difiipated in the operation ; 
and that if afterwards it be expofed to the 
air, it eafily x\\n%per dfliquiiim, much earth 
being left undiiTolved at the bottom of the 
vefi^el J and that, after it hath been feveral 
times fufed, if fome powder of charcoal be 
added to it, whilfl in fufion, a fulphureous 
mafs is produced, as if it was mixed with 
common brimftone^. 

But a much milder heat than Is required 
to fufe common fait, will feparate its acid 

7 See Hoffman's O^/. Pbyf. Chem. Lib. if. Obf. xvi. 

If credit may be given to Glauber, he could in a few 
hours fo change fea fair, that it would acquire a fiery na- 
ture, and ferve all the ufes of pot allies, and other lixi- 
vial falts. 


White Salt. S27 

fpirit from its alcaline principle, as I was 
taught by the following experiments. I 
took about half a pound of pure cryftals of 
bay fait from St. Ubes, and diflblved them 
in pure water j feveral portions of this folu- 
tion I mixed with fyrup of violets, and with 
the tindure of flowers of Cyanus, and ob- 
ferved that the blue colour of the fyrup and 
tindure was not changed either green or 
red, but rather heightened by the fait. The 
reft of the folution I boiled over the fire 
brifkly in a clean iron pan, till mofl of the 
water was evaporated, and the fait remained 
in a folid form at the bottom of the pan, 
but ftill retained fome moifture, and was 
not reduced to a perfedl drynefs. Some of 
this boiled fait being diflblved in pure wa- 
ter, and then mixed with fyrup of violets 
or the tindure of Cyanus, infl:antly turned 
the colour of thofe liquors into a grafs green. 
This experiment was often repeated ; and 
plainly Ihews, that the alcaline principle 
v/as predominant in this boiled fait, and 
that it had been deprived of a conflderable 
portion of its acid fpirit by the heat applied 
to it during its coftion. 

From, all thefe experiments we may 
therefore conclude, that the volatile acid 

Q_2 fpirit. 


228 T^he art of preparing 

fplrit, may eafily be feparated from the 
fixed alcaline principle of common fait, by 
more ways than thofe pradifed by chemifts 
in the difhillation of thofe acid fpirits ; and 
that when fait water is expofed to the fire, 
very Jittle or none of the fpirit of fait arifes 
while the heat applied is confiderably lefs 
than that which is necefiary to make rain 
water, or any other pure water boil j but if 
a greater heat be applied, fo that the water 
with the fait diflblved in it be kept continu- 
ally boiling till the evaporation be finiilied : 
then, during that part of the co6lion in 
which the water is only weakly impregna- 
ted with fait, no acid fpirit, or very little 
arifes ^ j but as foon as the water is fo far 
evaporated, that what remains contains about 
a fixth part ; or, if the water be vifcid, like 
fea water, about a twentieth part of fait, it 
then acquires fo great a heat in boiling as 
is fufiicient to feparate a confiderable quan- 
tity of acid fpirit from the fait, which fpirit 
therefore flies off along with the watery va- 
pours. And as the brine, during the eva- 

^ Thefe calculations are made upon a fuppofition, 
that the fea water ufed by Dr. Hales and Mr. Boyle in 
the above-mentioned experiments contained -*- part of 
fait. For 30 — i of 30 =;; 6. And 30 — \ of 30 ::= 

2(?. • 


White Salt. 229 

poration, continually becomes more fully 
iaturated with fait, and grows continually 
more ponderous, it therefore continually ac- 
quires a more intenfe heat in boiling, which 
greater degree of heat feparates a greater 
portion of acid fpirit from the fait j fo that 
the fpirit arifes ftill in greater quantities, in 
proportion as the evaporation is carried on 
farther ; and the fait being thus deprived of 
part of its acid fpirit, acquires an alcaline 
quality, and is alfo confiderably diminifhed 
in quantity, when the cod:ion is continued 
till all the water is evaporated. ' 

■ These obfervations hold true in the com- 
mon procefTes of preparing fait by codlion. 
For all who are acquainted with the method 
of making white fait unanimoufly agree, that 
the fait contained in brine or other fait wa- 
ters is confiderably diminifhed in quantity, 
when thofe waters are made to boil violently 
towards the end of the procefs, after the 
fait hath begun to cryflallize ; at which 
time the heat of the faturated brine, if kept 
boiling, is much more intenfe than that of 
boiling water. But the bittern which re- 
mains in the pan after the fait hath been 
extracted by fo intenfe a heat, is found more 
in quantity, than when a moderate heat is 
0^3 applied^ 

23^ ^^ ^''^ ^J pr sparing 

applied ; being increafed by the alcaline 
part oi common fait deprived of its acid fpi- 
rit, by the violent coition. The fait made 
with this intenfe heat, is of a fmall loofe 
irregular grain, and quickly grov\^s moift in 
the air -, for which reafon, the artifls fay, 
that it is not well cleared of the frefh. In 
order therefore, to obtain a larger quantity 
of fait, and of abetter kind, they conftantly 
llacken their fires, and boil very gently, as 
foon as they perceive the faline cryftals be- 
gin to form in the brine. But they do not 
thus prevent the fpirlt of fait from exhaling 
in confiderable quantities. For although the 
faturated brine only limmers or boils very 
gently, yet it then retains fuch a heat as is 
fufficient to drive off a confiderable portion 
of this fpirit j and a confiderable portion of 
it mufl alfo have exhaled before the time 
that the workmen flacken their fires, as ap- 
pears from the foregoing experiments. So 
that white fait prepared after the common 
methods, muft be deprived of a confidera-r 
ble portion of its acid fpirit, by the violent 
coction ufed in its preparation. 


W H I T E S A L T. 231 


Mojl kinds of white fait are rendered ifnptire 
by the mixture of various heterogeneous fub- 

In the common proceffes of boiling fait 
from fea water, a large quantity of calca- 
rlous earth, called fcratch, is obferved to 
feparate during the codlion. Part of this 
earth clofely adheres to the bottom and fides 
of the boiler, and there, forms a flony 
cruft. Another part of it floats loofe in the 
brine, in the form of a fubtile powder, un- 
til it is caft to the corners of the boiler, 
where, being no longer agitated by the mo- 
tion of the liquor, it fubfides into fmall flat 
pans placed there to receive it. But all of it 
cannot after this rude method be feparated 
from the brine j a conflderable quantity of 
it fl;ill floats therein, until it mixes with the 
ialt, and together with it is drawn out of 
the boiler. 

Most other kinds of fait water are greatly 
contaminated with the fame calcarious earth 5 
it abounds in the natural brines both of Eng^ 
land and Germany, fome of them contain^ 
jng as muck of it as fea water does of lait 5 
0^4 and 

232 ^'he art cf preparing 

and it is an advantage almcf!" peculiar to the 
Droitwich brine to be entirely free from any 
mixture of this terreftrial matter. Salt there- 
fore boiled from brine, as well as from fea 
water, is feldom without a mixture of this 
calcarious earth 3 fincc no greater care is 
ufed in feparating it from natural brine than 
from fea water, in boiling them into fait. 

The fame may alfo be affirmed of the 
fait refined from a folution of the Englifh 
foilil fait J in boiling of which, this earth 
is obferved to float about, and is colle(5ted 
into fcratch pans, as from other fait waters. 

Besides this calcarious fubftance, mofl 
kinds of brine hold a ferruginous earth or 
ochre, which is fometimes m.ixed with the 
fait, and renders it of a dirty colour. At 
feveral of the Chefhire fait works, where they 
ufe a very itrong brine, the firfl draught of 
fait, or clearing of the pan as they call it, 
is rendered fo impure by this, snd other he- 
terogeneous mixtures, that they throw it 
away as ufelcfs. 

The earthy fubftances mixed with fait, 
may eafily be difcovered by diflblving it in 
pure water, and fi ffcring the folution to re- 
main quiet, till all the g* ofsfubftances which 
were mixed with trie fait have fubiided to 


Whit e Salt. 233 

the bottom of the velTel. Moil kinds of 
boiled fait that I have had opportunities of 
examining, as fea fait, Chefhire brine fait, 
rock fait- refined in Chefliire and Ireland, 
when thus diflblved in pure water, conflantly 
let fall a white earthy fediment in confide- 
rable quantities ; and in moft of their folu- 
tions I have likev/ife obferved large fcales of 
fcratch which had been difunited from the 
fides of the fait pan. On moft of thefe fo- 
lutions there alfo arofe a frothy fcum, which 
was much more copious, and of a more 
dufky colour on the folutions of thofe falts 
which were mixed with butter and other 
additions, tlian of thofe which had been 
prepared without them. I have alfo ob- 
ferved coal duft, fand, and other grofs im- 
purities frequently mixed with feveral kinds 
of white fait. 

But befides the earthy and other grofs 
fubflances found mixed with white fait ; it 
is commonly rendered ftill more impure by 
a mixture of falts of a different nature. For 
in the procefs of boiling fait from fea water, 
it was obferved that a confiderable quantity 
of a poiiderous, fliarp, und:uous, bitter li- 
quor remained in the pan, after all the fait 
was extracted ; and that a confiderable quan- 

234 *^^^ ^^^ of p7'e paring 

tity of the fame bitter liquor alfo drained 
from the fait after it was drawn out of the 
pan. I^ow, although thofe who boil fea 
fait fufFer the bitter liquor to drain from it 
for feveral days; yet it cannot be imagined 
that all the bittern is, after that manner, 
feparated from the fea fait ; a confiderablc 
quantity of it doth undoubtedly ftill adhere 
to the fait in a liquid form 3 and a large 
quantity of the bitter purging fait is often 
reduced into cryftals along with the com- 
mon fait ; and fometimes may be difco- 
vered in it even by the tafte. And thofe 
who know how difficult a matter it is to 
refine nitre, and other falts, and feparate 
them one from another, and render them 
pure by cryftallization, will readily con- 
clude, that it is almoll: impoffible to fepa- 
rate the common fait entirely from the other 
falts contained in fea v/atcr, after the tumul- 
tuary manner in which the procefs of boiling 
fea fait is ufually performed. 

Moreover moft kinds of brine fait are 
probably alfo rendered impure by a mixture 
of the bitter purging fait, and other calca- 
rious falts. The bitter purging fait is ob- 
ferved greatly to abound in the bowels of 
the earth, and to impregnate, not only the 


White Salt. 235 

ocean, but Mfo feveral lakes, as the lake of 
Sodom or Dead Sea, whofe waters are 
thereby rendered extremely bitter. It is 
probably this fait that gives moft of the 
fprings in Arabia, and fome other parts of 
Ada their bitter tafte, and renders them un- 
potable. And in England, we find a vaft 
number of fprings impregnated therewith, 
and together with it almoil conftantly to 
hold a muriatic fait ; fo that this bitter fait 
and common fait are ufually found together 
diflblved in the fame water ; as in the brine 
of Cheflnre, if in this particular, credit may 
be given to Dodor Leigh. Rock fait like- 
wife often holds a mixture of this bitter 
fait ; it is difcovered by the tafte in the fof- 
iil fait of Armenia, and renders the fait of 
the mountain Had-deifa fo bitter, that it is 
unfit for domeftic ufes until it hath under- 
gone an accidental purification \ And that 
moft of the brine fprings in Germany hold 
a kind of bittern, we are aftured by Dr. 
Fred. Hoffman j although from his experi- 
ments their bittern feems to contain much 
more of the ftiarp pungent muriatic calca- 
fious fait, than of the bitter purging fait 

' See note from the Rev. Dr. Shaw in the intro- 


236 ^he art cf preparing 

before defcribed. It can therefore fcarce be 
imagined, that the Englifli brine falts are 
wholly free from a mixture of thefe calca- 
rioiis falts of the bittern j efpecially when it 
is confidered that the brine fait makers are 
not accuftomed to throw away any of their 
liquor ; but conftantly mix the leach brine, 
which remains in the pan, or drains from 
the fait, with the brine frefli drawn into the 
pan, and fo boil them up together into fait. 

As to the refined rock fait made in Che- 
fliire, it not only contains all the heteroge- 
neous falts of the native foiTil fait ; but alfo, 
all the bitter falts of the brine or fea water, 
with which the foflil fait is refined. For 
neither do the refiners ufually throw away 
any of their leach brine ; but mix it in the 
pan with their frefli folution, and there- 
with reduce it into fait, hardening up all 
together in their hot houfes. 

Besides thefe calcarious falts, mofl kinds 
of boiled fait are alfo mixed with a fixed 
mineral alcali. This alcaline fait may eafily 
be difcovered in the marine bittern by fyrup 
of violets, which it inftantly turns green ; 
and in the fame manner it may probably 
be difcovered in mofh kinds of leach brine, 
by thofe who have opportunities of trying 


Wh ite Salt. 237 

them. I have frequently mixed various 
kinds of white fait, as fea fait, brine fait, 
and refined rock fait, with about an equal 
weight of pure water ; and after the water 
had dilTolved near as much of the fait as it 
could keep fufpended, have poured oiF the 
clear folution ; and, when the fait had not 
before been long expofed to the air, almoft 
conflantly obferved that its clear folution 
prepared in the foregoing manner, being 
mixed with the tincture of flowers of Cya- 
nus, turned it from a fine blue, to a green 
colour 3 which change of colour plainly dif- 
covered that the fait contained fome mixture 
of a mineral alcali. Some of thefe folutions 
would inflantly change the colour of the 
tindlure, but others not till after twelve, or 
twenty-four hours, and then only to a pale 
green. But the folution of fine Portugal 
fait made after the fame manner, had no 
fuch effe6t upon the tincflure, but rather 
heightened its blue colour ; and this colour 
it retained much longer when mixed with 
the laft mentioned folution, than when mix- 
ed with pure water in the fame proportion. 
In making thefe experiments care fliould be 
taken that the folutions be perfedly clear, 
and free from any mixture of calcarious 

earth j 

238 ^e art of preparing 

earth ; otherwife the change of colour may 
proceed from the alcaline earth, and not 
from any perfed; alcaline fait. From the 
experiments made by boiling pure bay fait 
as before related^, it appears that the alca- 
line fait found mixed with white fait, may 
fometimcs be the alcaline principle of com- 
mon fait deprived of its acid fpirit by violent 
coition. At other times, it may have ex- 
ifted in the form of an alcali in the fait wa- 
ter before its co(flion. In both cafes its na- 
ture and effedis will be nearly the fame. 

Besides the various kinds of falts and 
earthy fubflances before taken notice of; 
we are affured by Mr. Boyle, that common 
fait fometimes participates of combuftible 
fulphur. That moft kinds of natural brine 
contain a fulphureous principle, is very cer- 
tain ; and this principle may fometimes b& 
of fo fixed a nature, or f ) entangled with 
the fait, that it cannot eaiily feparate from 
it, and fly off in boiling. Altho' it is proba- 
ble that mofl of the fulphureous fubftance 
mixed with boiled fait may rather be arti- 
ficial than natural ; and may proceed from 
the butter and other undiuous fubftances 
ufed by many fait boilers j which incorpo- 

* Under the foregoing lemma pag. 227. 


White Salt. 2351 

rating with the fait, efpecially when it is 
burnt and rendered alcaline by violent heat, 
may with it form a kind of liver of fulphur, 
as in the experiments before related 5. The 
like may fometimes happen when fat blood 
is ufed to clarify the brine. 

Also flower, rofin, and many other ad- 
ditions vi^hich the operators ufe, feem fcarcc 
to have any good eifed:, but load the fait 
with a ftill greater variety of impurities, 


White fait J by the *viclent coBion commonly 

ufed in its preparation, is rendered lefsjit 

for preferring flefJjy ffh, and other provi- 

fions, than it would be if prepared with a 

jjjore gentle heat. 

It is well known to chemifts, that com- 
mon fait, by means of fire may eafily be 
refolved into two principles ; and of them 
again may be compofed. Thefe principles 
are a fixed alcali, and a volatile penetrating 
acid fpirit. To the laft of thefe principles 
is owing the power and efficacy which fait 
hath upon animal fubftances j whereby it 
gently contracls and hardens their folid parrs, 

' See page 233. 


240 T'he art of preparing 

retrains the inteftine motions of their fluids, 
and fopreferves them from corruption. That 
the acid fpirit of fait pofl'efTes thefe qualities 
in a moft extraordinary degree hath long 
been known to anatomifts -, amonglt whom 
it hath been a fecret to mix a few drops of 
it with the fermented fpirits in which they 
preferve their injedlions, and other curious 

The Rev. Dr. Hales found that this acid 
fpirit would prevent common water from 
putrifying. He alfo experienced that beef 
might be preferved fweet a conliderable 
time in water, by mixing with it this acid 
in the fmall proportion of three drops to an 
ounce of the water. 

"^ " Into two ounces of the laft portion 
'' of the diilillation ,to drinefs of fea water, 
" the fame gentleman put a fmall piece of 
" frefh beef: and put beef alfo into the like 
" quantities of well-cured fea water, (which 
" had no fpirit of fait mixed with it) and 
" alfo of rain water. In i^v^w days the two 
" lafl: were become fetid and putrid, and 
*' the water thick and cloudy j whereas, 
*' the beef in the very bad fea water (im- 
" pregnated with fpirit of fait) did not pu- 

^ Dr. Hiles Philofophical experiments y pag. 15, i'^. 

" trify. 

WH I T E S A LT. " }int 

irlfy, nor was the water turbid, but 
clear as at iiiil:, though kept Cevcn or 
eight weeks with the fleih in it. And it 
was obfervablt!, that the reftringent qua- 
Hty of the bad diflilled fea water was fo 
great, that it contrafted the fibres and 
blood veiTels of the beef, fo that no blood 
could ifTue out of them j as it did from 
the iirft day from the beef in the other 
glailes, which had good wholfome dif- 
tilled fea water, or rain water in them.'* 
These experiments fufficiently fliew the 
extraordinary efficacy of fpirit of fait in 
preferving animal bodies from corruption. 
But this fpirit is of too (harp and corrofive a 
nature, and too noxious to the human body 
to be ufed as a condiment for food, uniefs 
its too great acrimony be allayed by the al- 
caline principle of common fait. For this, 
as well as all other acids, ftrongly coagulates 
the blood of animals, when mixed there- 
with : whereas, neutral falts have no fuch 
efFe(5l ; and feveral of them, when dilTolved 
in water, may even be injcded into the veins 
of animals, without doing them any great 
prejudice. Common fait, mod efpecially, 
is found friendly to animal nature ; its acid 
fpirit being fo tempered by its alcaline prin- 

R ciple^ 

140. T^he art of preparing 

ciple, that, when mixed with blood, it ih 
thereby prevented from growing too thin 
and putrid, to which it hath a natural ten- 
dencyj and the texture of the blood is thereby 
alfo preferved fo intire, that for years it pre- 
ferves its gummy balfamic quality. This 
hath been experienced in beef pickle j the 
animal juices in which, after it had been 
kept for years, have coagulated by heat, as 
if they had been blood frefli drawn from a 
vein ; and this pickle hath often been ufed 
by the fait boilers to clarify fea water inftead 
of whites of eggs. Common fait, therefore, 
as it is of a middle nature, between acids 
and alcalics, hath neither the bad effedts of 
the one, nor of the other, upon the juices of 
animals. For, when mixed with blood, it 
does not coagulate it like acids j neither 
does it thin the blood and deflroy its gluti- 
nous texture, and reduce it to a tabid cor- 
rupted flate, as all alcalies, whether iixed or 
volatile are found to do. 

The alcaline principle therefore, of com- 
mon fait, when feparated from its acid fpi- 
rit, is fo far from having any cmcacy as a 
condiment, that on the contrary, it corrodes 
and dilTolves animal fubllanccs, and pro- 
motes their putrefad;ion. All alcalies are 


WiiiTiE Salt. 245 

found to have thefe efFeds, efpecially the 
more fixed kinds, as they ilrongly attra(5l 
und:uous and aqueous fubftances, and by 
that means quickly penetrate the flefh of 
animals ; infinuating themfelves between its 
fibres, and diffolving their cohefion ; when 
mixed with the juices of animals, they alfo 
ad: violently upon the neutral falts which 
they contain, uniting to the acid principle 
of thofe lalts, and feparating it from the vo- 
latile alcali to which it before was joined, 
and thus exciting inteftine motions in thofe 
juices, and promoting their corruption. Sur- 
geons, therefore, know no better cauftic for 
corroding the flefh of living bodies, than that 
which is compofed of foap and quicklime. 
And thofe who are employed in dreffing 
leather, find nothing fo proper to tender 
Ikins, and reduce their external parts to a 
femi-putrid ftate, as lime mixed with wa- 
ter J in which they fleep their fliins in order 
the more readily to feparate the hair from 
them. Thefe obfervations fufficiently fhew 
the effeds of lixivial falts and quicklime 
upon animal fubflances, and how by them 
the folid parts of animals are corroded, and 
their fluids rendered fliarp and thin, and the 

R 2 whole 

' 244 ^'^'^ ^^^ of preparing 

whole quickly reduced to a ftate of corrup- 

And that the alcaline principle of com- 
mon fait hath a very great affinity to the 
lixivial fait of vegetables is plain and evident, 
fince it is of a fixed nature foluble in water, 
and hath the fame efFedls with thofe lixivial 
falts upon fyrup of violets, and other blue 
tindlures of vegetables ; like them it greedily 
imbibes the aereal moiflure, and with it runs 
per deliquhim ; and like them alfo it readily 
unites to the phlogiftic principle of charcoal, 
and with it forms a fulphureous mafs, as 
hath before been obferved. The lixivial 
fait of vegetables will even fupply the place 
of this alcaline principle ; and when mixed 
with the acid fpirit of fait, is with it con- 
verted into a neutral fait, which does not 
appear in any refpedt different from com- 
mon falt+. 

^ Except it fliould be found that the folution of this 
faftitious common fair, made in pure rain water, v/ill 
not grow turbid when mixed with the folution of fait 
of tartar. In which particular it may probably differ 
from all kinds of marine fair, whether bay fait or boiled 
fait, that I have had opportunities of examiuing ; whofe 
clear folutions conftantly grew white when mixed with 
the faid folution of fait of tartar, contrary to v.'hat is af- 
ferted by Monf. du Clofs in the Mem. de P Acad, Royale 
des Sciences. And thefe folutions, thus mixed together. 


Wh I TE Salt. 245 

Common fait therefore owes its property 
of preferving animal fubftances folely to its 
acid fpirit ; and in proportion as it hath 
more or lefs of this acid, it is more or lefs 
ftrong ; that is to fay, it is more or lefs 
fharp and pungent to the tafte, and hath a 
greater or lefs power of preferving animal 
bodies from putrefaction. For it appears, 
that fait, deprived of a confiderable part of 
its acid fpirit, may yet retain the form of fait, 
although it cannot then be efteemed a per- 
fed: fait, but rather a kind of decrepitated 
fait, in which the alcaline principle is pre- 
dominant. Such fait is commonly of a 
fmall, loofe, irregular grain, and is difpofed 
to grow moift in the open air, and is faid 

conftantly depofited a very light earthy fedimenr, and 
ill feveral of them, part of this earthy matter was alfo 
fufpended like a cloud j and more of the folution of tar- 
tar being added to the mixture after it became clear, ic 
did not again grow white and turbid ; which ftiews that 
common fait only contains a fmall portion of this white 
earth which n^ay thus be precipitated from it. I alfo 
obferved a fmall portion of a very alcaline earth to fet- 
tle in the folution of the white fait prepared by vio- 
lent codlion from bay fait, after the manner before 
related. Salt after fuhon, being fufFered to run per d^- 
llquium^ hath alfo been obferved to depofite an earthy 
matter, as before related. All which obfervations feem 
to prove, that the alcaline principle of common fait is 
not all of it a perfed fixed alcaline fait j bat that fome 
part of it is an alcaline earth approaching to the nature 
t)f quicklime. 

R 3 to 

£46 The art of preparing 

to be weak, becaufe of a flat tafte, and im- 
proper for curing provifions for exportation 
into hot countries. 

And fuch, in a greater or lefs degree, are 
moft kinds of white fait now made, being 
deprived of a confiderable portion of their 
acid fpirit by the violent cod:ion ufed in their 
preparation, as hath before been demon- 
ftrated. And this is confirmed by the prac- 
tice of the Chefhire fait boilers ; who, when 
they formerly boiled their fait in a very 
hafty manner, found it unfit for keeping, 
and only made it for prefent fale. Whereas, 
now by ufing a much flower heat, they pre- 
pare fait much fitter for preferving provinons; 
and by applying more gentle fires than or- 
dinary, they prepare their fliiveiy fait j which 
is the fl:rongeft fait, and of the firmefl: and 
largefl: grain of any that they rrake. So 
that in proportion as the heat made ufe of 
in boiling v/hite fait is greater or lefs, a 
greater or lefs quantity of the acid fpirit is 
difBpated ; the weakefl: fait being prepared 
by the mofl: violent heat. 

The Britifli fait boilers, therefore, though 
they have made feveral improvements in 
their art, have not yet brought it to the ut- 
njofl perfedion 5 for the heat which they 

White Salt. 247 

flill ufe is fo intenfe, that by it a confide- 
rable portion of the acid fpirit of fait is 
wafted ; and the fait which they prepare is 
always lefs fharp and pungent than bay fait, 
which is extracted by a more gentle heat ; 
and for this, and other reafons, hereafter to 
be given, is lefs proper than bay fait for 
curing provifions. The Dutch, therefore, 
when they would make a kind of white fait 
iit for preferving provifions, very prudently 
take care to wafte the water, in which the 
fait is diifolved, by a very flow and gentle 
heat, not much greater than the folar heat 
in the warmeft climates, and by this means 
they obtain a ftrong and vigorous fait, fully 
faturated with its acid fpirit, and extremely 
proper for the ufes for which it is intended. 
For by fuch a heat none of the Ipirit of fait 
is diffipated, as appears from the experiments 
of Mr. Boyle and others, before related. 


^be heterogeneous fubjiances which are com- 
monly mixed with white fait ^ render it lefs 
proper for preferving provifions^ that}, it 
would be if feparated from them^ 

The heterogeneous fubftances found mix- 
ed with moft kinds of white fait are chiefly 
R 4 the 

248 ^he art of preparing 

the calcarious earth called fcratch, the bit- 
ter purging fait, and the muriatic calcarious, 
and alcaline falts before defcribed. 
"The calcarious earth which commonly 
abounds in boiled fait (and particularly in 
fea fait, and moft kinds of brine fait ufed in 
England) can no ways be proper for pre- 
ferving meat, approach 'ng too near to the 
nature of lixivial falts a;: d quicklime'. A 
fubftance of fo alcaline a nature as fcratch, 
can therefore in no wife contribute to pre- 
ferve the ficfli of animals ; but, on the con- 
trary, muft rather corrode and deflroy it, and 
promote its putrefadicn. 

And hence it probably is, that the Droit- 
Vvich fait, which is perfed:ly free from 
fcratch, hath, by impartial judges*, been 
efleemed a ftronger fait, and litter for pre- 
ferving proviiions, than any kind of brine 
fait, prepared after the fame way with it, in 
other parts of England. 

As to the bitter fait, and the muriatic 
calcarious fait of bittern, of all neutral falts 
they are foluble in the leaft quantity of wa- 
ter, and mofl greedily imbibe the aereal 
moiflure, and moft readily unite to unduous 

' See part ii. chap. ii. § %. 
* As by Dr. Lifter and others. 


Whi t e Salt. 249 

fubftances. So that when mixed with com- 
mon fait, they difpofe it to relent and grow 
foft in the open air 5 and when apphed with 
it to the flefh of animals, they prey upon 
the fat, and with it unite into a kind of 
foap 3 they alfo do not fufFer the fait to fix 
and harden in the meat, but difpofe it to 
difTolve with the juices, and to run out with 
them in pickle -, and the meat, being thus 
deprived of its fat and juices, is left open 
and fpungy, fo that the air eafily penetrates 
and corrupts it. 

The fixed alcaline falts, fo frequently 
mixed with white fait, will have the fame 
effeds upon the flefli of animals with the 
bitter and calcarious falts before related; 
moreover they will corrode the folid parts of 
animals, and promote inteftine motions in 
their fluids, and render them thin and acri- 
monious, as hath before been explained. 
And to thefe alcaline falts feem chiefly ow- 
ing the difagreeable red colour, and tabid 
Hime, frequently obferved in beef, that hath 
been pickled with weak and impure fait. 

Those therefore who prepare brine fait 
in England, feem guilty of a capital error, 
when they mix the leach brine which drains 
from the fait, or remains in the pan after 


2^0 ^he art of preparing 

the procefs is finifhed, with the brine frefh 
drawn from their ciftern, and boil them up 
together into fait. For by this means they 
render their fait impure, and lefs fit for do- 
meftic ufes ; as it hath mixed with it a much 
greater proportion of alcaline, bitter, and 
calcarious falts, than it would have if the 
leach brine was either thrown away, or ap- 
plied to other ufes. 

They alfo commit a yet greater miflake, 
who, when they refine rock fait with fea 
water, do no throw away their leach brine, 
or bittern, but mix it in the pan with their 
folution, and harden up all together into 
fait. And it feems entirely owing to this 
very faulty method, that the Chefliire fofiil 
fait refined with fea water, is of a worfe qua- 
hty than their brine fait. For as their brine 
is only a folution of rock fait made in the 
bowels of the earth, often in very impure 
water, there could be no reafon why the 
brine fait Ihould be better than the refined 
rock fait, if both were boiled after the fame 
manner j the rock fait having firfl been dif- 
folved, not in fea water or impure brine, 
but in purer rain or river water. 

Sea fait therefore prepared by the heat of 
the fun, as it is more free from fcratch and the 


White Salt. 251 

falts of the bittern, than mod kinds of white 
fait, is more proper for preferving flefh and 
other kinds of provifions. For the marine bay 
fait is not extracted in a hafty and tumul- 
tuary way, but by a flow and gentle heat ; 
fo that when a certain portion of the water 
hath exhaled, the calcarious earth feparates 
from it, and fubfides in the brine ponds, 
being depofited before the brine enters the 
fait pits 3. The brine, thus freed from its 
calcarious earth is, received into the fait pits, 
where the faline particles concrete together, 
and after they have united into large cryftals, 
are drawn out pretty free from the falts of the 
bittern,which remain dilTolvedin their watery 
vehicle. For chemiils have obferved, that 
when different kinds of falts are left to cry- 
flallize in a faline lixivium, thofe conftantly 
fhoot firft which require the largefl quantity 
of water to diflblve them 5 and very little of 
the more foluble falts will form into cryftals 
while there remains a fufficient quantity of 
water to keep them dilTolved. The bitter 
brine which remains in the fait pits, is fre- 
quently drained out of them. And if any of 
the falts of the bittern happened to be mixed 
with the bay fait, they are often wafhed out 

3 See the foregoing defcription of the French fa!tmar{h. 
Pare j. Chap. iv. 


252 I'he art of preparing 

of it by rains, while it lies in heaps expofed 
to the air. 

Thus a ftrong muriatic fait is obtained 
from fea water, turgid with its acid fpirit, fufH- 
clently freed from calcarious earth and bittern, 
and very proper for all culinary ufes. For 
although it hath often a confiderable quantity 
of flimy mud, clay, and fand mixed with it, 
which give it a dirty colour, yet thefe im- 
purities do not penetrate the flefh of animals, 
but only adhere on its outfide in a dirty crufl:, 
which may eafily be wafhed off; fo that 
they indeed make the meat more unfightly, 
but have no other bad effects upon it, and 
do not render the fait with which they are 
mixed unfit for preferving it. 

As to the ftrong Dutch refined fait, it Is 
certainly of all kinds of fait now made, the 
mofl: pure, and in that rcfpedt the mofl pro- 
per for preferving provifions. For it retains 
fcarce any calcarious earth, or falts of the 
bittern ; it is alfo free from mud and other im- 
purities with which bay fait is contaminated 5 
and if it acquires any alcaline quality by boil- 
ing, that is corrected by a mild acid which 
is added to the brine. It is not, therefore, at 
all to be wondered at, that the Dutch white 
herrings cured with this fait, look much more 


Wh I TE Salt. 253 

fair and beautiful, and keep longer, and 
consequently fell for a better price, than 
thofe that are preferved with other kinds of 


From fea ivater, fojjil fait, or natural brine ^ 
to prepare a kind of white fait proper for 
airingffijfefj, and other provifions. 

By the foregoing facts and arguments it 
feems to have been fufficiently demonftrated, 
that the common kinds of boiled fait are in 
fome things deficient, in others redundant ; 
that they want a confiderable portion of their 
volatil acid, without which the other principles 
of fait have no efficacy as a condiment, but 
are like a dead body deprived of its quicken- 
ing fpirit ; and that they abound with many 
impurities, as earths, fulphurious bodies, 
heterogeneous falts, hurtful additions of va- 
rious kinds, afhes, foot, coal, &c. which, in- 
ftead of preferving, defile and corrupt the 
fiefh of animals to which they are applied. 

Moreover, it feems to have been fully 
proved that thofe kinds of fait which 
are fully faturated with their acid fpi- 
rit, and fufficiently depurated from hetero- 


254 ^^^ ^^^ tf preparing 

geneal mixtures, are extremely fit and pro- 
per for preferving iifh, flefli, and other kinds 
of provifion. 

And forasmuch as all kinds of common 
fait, when pure and perfedl, are found to be 
of the fame nature and to agree in the fame 
qualities ; from thefe premifes may therefore 
be drawn the following conclulion : That 
any kind of common fait which is perfecflly 
free from all heterogeneous mixtures, and 
hath not been deprived of any part of its 
acid fpirit, is extremely fit and proper for 
curing all forts of provifions. 

The requifites in the foregoing problem 
will therefore be fully fatisfied, if from fca 
water, foffil fait, or natural brine, white fait 
be prepared free from all impurities, and no 
ways weakened by a diffipation of its acid 

This may be fully effeded at two opera- 
tions. In the firft of which, from the fait 
water mufl: be prepared a good kind of 
white fait, more fully impregnated with its 
acid fpirit, than fait boiled after any of the 
common methods. And in the fecond ope- 
ration, the white fait thus prepared, muft 
be refined from the impurities with which it is 
ilill mixed, and reduced to a purer and 


White Salt. 2^^ 

Wronger kind of fait ; after nearly the fame 
manner that bay fait is now refined in Hol- 

In the firft procefs, if fea water be ufed, 
the following method is recommended -, by 
which a marine fait may be prepared better 
in quality, and alfo at a lefs expence, than 
by any of the methods of boiling fea fait 
that are now in practice. 

First, let the fea water be heightened 
into a flrong brine by the fun, after the me- 
thod pradifed in Hampfhire, and other 
parts of England ; or (which will be a better 
and lefs expenfive method) in a fait marfli 
conftrudted after the French manner, from 
which large quantities of bay fait may be 
drawn at proper feafons -, and when the wea- 
ther is lefs favourable, brine may be col- 
ledted into large cifterns there to remain 
until it is drawn out to be boiled into fait. 

For this purpofe a faltern mufl: be eredled 
adjoining to the fait marfh, and in it muft be 
placed a large boiler or fait pan made of 
iron. The bottom of the pan may be of a 
fquare figure, forty feet on each fide, and its 
depth may be eighteen inches'. Or the 

' If the pan is made of a fquiire figure, the fcrarch 
may conveniently be colledled ar its corners into jBat 


256 'T'he a?'f rf prepar'ing 

pan may be made of a cylindrical form, forty 
feet in diameter, and eighteen inches deep ; 
which is the moll: common fize and figure 
of the pans ufed in Holland ". The furnace 
over which the pan is ereded may have 
four mouths, made on the oppofite fides, at 
equal diflances, for the conveniency of re- 
ceiving fuel. The fire may be made on a 
hearth , and within tlie furnace muft be 

lead pans. But if of a cylindrical form, the fcrarch may 
be raked from iis botroni, as at the Len)n"iington works. 
And if any fak be rake 1 up with the fcratch, it need not 
be loft, but may be diflblvcd from among it by water. 
Or if a confiderable quantity of Icratch remains mixed 
with the flit, it will with other grcfj impurities fubfide 
in the brine, when the fait is again diflblved in water, 
as dire(fted in the fecond procels. 

At one corner or fide of ihe pan may be fixed a 
pipe with a cock, through which the bittern maybe drawn 
our, whenoccafion require?, and thither there maybe a 
gentle fall from all other parts of the bottom. It is 
true indeed that in the common proceHls of making fair, 
the pans are fo fhakcn by the violent boilmg that they 
do not long retain the fame pofition, by which motion 
of the pans their joints arc loofened, and their bottoms 
often cracked and bulged ^ fo that by fuch accidents 
a pipe might foon be rendered ufelefs. But thefe acci- 
dents might probably be prevented by faflening the pan 
down in its btuation with flrong bars of iron, firmly 
fixed in the earth, and hooked clofe to the corners and 
fides of the pan. 

* It may probably require a large fait marfli or even 
feveral fait marfhes, in order to keep a pan of this fize 
conftantly at work. 

I ereded 

White Salt. ^57 

€re6led pfoper pillars of brick or mid-fea- 
thers ; and, if occalion requires, llrong pofts, 
and crofs bars of iron, to fiipport the bottom of 
the fait pan. There muft 2.K0 be four fun- 
nels for conveying away the fmoke, placed 
at equal diilances between the mouths of the 
furnace. If the pan be fquare^ the funnels 
may be carried up at its four corners, and 
the mouths may be under the middle of its 
four fides. The mouths mufl all have doors 
fitted to them very clofe j and the funnels 
for conveying away the fmoke, mufl: have 
regifters 5 all which may be opened or fliut, 
as occafion requires, for the more convenient 
regulating of the fire. 

Things being thus prepared, let the fait 
pan be filled with flrong brine, drawn from 
the ciflern, and well cleared from its muddy 
fediment. Then, kindle the fire (pit coal 
will ferve very well for this ufe, and will, in 
all parts of Great Britain, be much cheaper 
than cinders and the moll parts, than any 
other kind of fuel) and mix a fufficient quan- 
tity of whites of eggs with the brine to clarify 
it from its vifcous matter, and other light 
impurities. Let the brine at firfl boil gently, 
and when the fcum hath all arifen, take it off 

S affer 

'258 'The art of preparing 

after the manner before direded ^ As fooiir 
as the brine is fkimmed, abate the fire, and 
only let a moderate heat be applied, fuffi- 
cient to keep the brine of a fcalding heat, 
which may be a heat of about two hundred 
degrees inFarenheight's thermometer. When 
the fait begins to grain, rake out the fcratch, 
which will then be fallen to the bottom of 
the pan. When the brine is thus fully de- 
purated, in order to correct its alcaline quali- 
ty, a proper quantity of four whey may be 
added to it, which can do no harm, and 
hath long been ufed by the Dutch with fuc- 
eefs'^. After the whey hath been added, the 
brine mufl be kept of a fcalding heat all the 
time that the fait is graining or forming into 
cryftals. And when moft of the fait is cry- 
flalllzed, and lies in the pan almofl dry on 
its furface, the fire muft be damped by {hut- 
ting the doors of the furnace, and the re- 
gifters } and the fait muft be drawn from the 
liquor to the fides of the pan, and put into 
drabs, or other proper veflels, till all the 

3 Part ii. Chap. ii. Sedl. i. 

4 The alcaline fait will by this acid whey be con- 
verted into a neutral (alt, refembling the Tartarus re- 
generatus, which will remain diiTolved in the bit- 


White Sal t.' b^'9? 

l^ltter liquor is drained from it ^ and then it 
will be fit to be ufed in the fecond pfocefs 
of refining. 

The fait pan, after every fecond or third 
time that this procefs is finiflied, mufl be 
emptied of the bittern ; and at proper times 
mufl alfo be cleanfed from the flone fcratch 
adhering to it. 

Thus may be prepared a good kind of 
lea fait, flronger, and of a much firmer and 
larger grain than any kind of common white 
fait made by the methods now in ufe. And 
after this manner may alfo be prepared a 
fait for the table, better in quality, and at 
a lefs expence than by the common methods. 
Only as fuch fait is required of a fine grain, 
it may be granulated with quicker fires than 
here directed, and may be drawn out of the 
pan before it hath lain long enough to form 
into large cryflals j fo that it may be taken 
out at five or fix draughts during the procefs. 
The fecond and third draughts will be the 
beft fait, being the mofl free from fcratch, 
and the falts of the bitterii. 

After the fame manner a good kind of 
white fait may be extracfted from natural 
brine ; and likewife from a folution of rock 
fait in weak brine or fea water. 

S 2 - JBtjx 

^66 ^^ ^^^ of preparing 

But if Inftead of ftrong brine, fait watef 
as drawn from tlie fea be ufed in this pro- 
cefs, then it may be proper to have a fait 
pan of twice the capacity of the pan above 
defcribed ; fo that it may be a yard in 
depths, and forty feet in diameter. The 
fea water received into this pan, after it hath 
been clarified with whites of eggs, may be 
made to boil very violently ^, until one half, 

5 Wc are told of pans of this depth being ufed at 
feme foreign fak works, as at Inn'ihall and Roche ^ and 
fuch are ufed in England at the copperas works. An 
addition made to the depth of the pan by heighten- 
ing the fides with flrong llieets of lead; and alfo 
covering with them a rim of timber fixed round the 
top, may make the pan of double its former capacity, 
at a fmall increafe of coft. What efFedt fuch a weight 
of water may have upon the bottom of the pan, and whe- 
ther it will require greater fires to boil ir, or whether the 
evaporation will be proportionably quicker in fuch deep 
pans than in Ihallower, are queftions which may beft 
be determined by experiments. Certain it is, that with 
luch pans there will be much lefs trouble in filling them 
up, and clarifying the brine ; and alfo much lefs danger 
of burning the fair, and wafting its fpirir, than in flial- 
lower pans. 

^ The violent boiling, here direded, will greatly fhorten 
the procelh, and will not much weaken or wafte the 
fak by dillipating its acid fpirit. For from Dr. Hale's 
experiments, it appears that fcarce any of this fpiric 
arifes from boiling Tea water until more than one third 
of the water is evaporated. And when the fea water 
hath been clarified from its vifcous matter, it is proba- 
|)le, from the fame gentleman's experi agents, that little 

3 or 

White Salt. 261 

or eighteen inches depth of it, be evaporated j 
and then the pan may be filled up with 
fea water a fecond time, which mufl: be 
clarified, and boiled down a foot in depth ; 
and then filled up a third time, and clarified 
as before. After which the liquor mufl be 
evaporated to a flrong brine, taking care to 
lefTen the fire as the brine increafes in 
itrength, and when it becomes fo flrong as 
to contain about a fifth part of fait, then 
only to uie a fcalding heat; taking out 
the powder fcratch when the fait begins 
to fall, corredling the alcaline quality of 
the brine with four whey, and graining the 
fait with a fcalding heat, as before di- 

The white fait being prepared according 
to the methods above propofed : Then, in 
the fecond procefs of refining, take a fufH- 
cient quantity of this white fait, put it into 
a large ciflern made of wood, or bricks and 
clay ; add to it as much pure river water 

of this fpirit will arife before half of the water is evapo- 
rated ; as directed in this procefs. Bat if the violenr 
coftion be ccncinued till the fait begins to grain, and 
the brine afrerwards be faffercd to firemer during the 
whole procefs, rjccording to tlic common practice i the 
fait will be grearly diminiHied in quantiry, and Wt^ak- 
cijed in ftrength by thedidipation of i[sacid fplvlL 

S3 a^ 

"262 ^he art of preparing 

as will be fufficient to reduce it to a ftrong 
brine, almofi: fully faturated with fait ; when 
the fait is diifolved, let the brine fland quiet, 
and if any fcum arifes, take it off: A large 
fediment will fall to the bottom of the ciftern, 
which, when all is fettled, the clear brine is 
fit for ufe. 

The fait pan moft proper for working 
this brine is the fame that is propofed for 
preparing white fait from brine in the lirft 
procefs. The pan will be more proper for 
this ufe, when its in fide is covered with a 
crufl of fcratch, than immediately after the 
faid crufl hath been picked off it. 

The pan being carefully cleanfed from 
bittern, the clear folution of white fait, pre- 
pared as before directed, mufl be drawn in- 
to it, out of the ciflern, by troughs, cranes, 
or pumps J care being taken that all the cal- 
carious earth, and other impurities of the 
white fait, fettled to the bottom of the ciflern, 
do there remain undiflurbed. The fire mufl 
then be kindled in the furnace (pit coal will 
ferve very well for this ufe) by which the 
watery part of the brine mufl be flowly eva- 
porated ; care being taken that the heat ufed 
be fo mild and gentle that none of the faline 
fpirit be feparated by it. The heat of the 


White Salt. 263 

brine during the whole procefs from firfl to 
laft, muft therefore be equal and regu- 
lar, and confiderably lefs than the heat of 
boiling water j perhaps a heat of one hun- 
dred and fixty, or one hundred and eighty de- 
grees in Farenhelght's thermometer may be 
the moft proper. A little experience will 
fliew the greateft heat that fait can endure 
without any diifipatlon of its acid fpirit ; and 
that is the heat here propofed to be ufed. 
The expert artift, by means of the reglfters 
in the chimneys, and the doors of tjie fur- 
naces, may {o regulate the fire, as to keep 
the brine coflantly heated to a certain degree 
of the thermometer, if fuch exadnefs fhould 
be required. 

When the evaporation is fo far advanced 
that little faline cryftals begin to appear on 
the furface of the brine, then may be added 
thereto a fufficient quantity of the acid mu- 
riatic fpirit, fo that neither the acid nor the 
alcaline principle of the fait may remain pre- 
dominant 7. Which being done, the eva- 

7 The quantity of acid fpirit here propofed to be added 
may be exadlly determined by proper alTays ; for if ic 
be found by experiments that ;i gallon of the brine 
requires one, two, or three drops of the fpirit to (arurare 
ir^ from thence may be known che quantity reqyired to 
faturace all the brine contained in the pan. 

S 4 poration 

264 'The art of preparing 

poration muft be continued until fo much 
fait is formed in the pan that its furface is 
almoll dry. The doors of the furnace and 
regifters muft then be clofed, and the fire 
fmothered out j and the fait, which will be 
found in large clear cryftals, mufl be raked 
to the fides of the pan, and, when it hath 
drained there a little time, muft be taken 
out and put into drabs or other proper vcfTels 
to drain further from the fuperfluous brine, 
and then will be fit for fale. 

The flrong brine which remains in the 
pan after the refined fait is drawn out, and 
the brine that drains from it, ought not to 
be mixed with the folution intended to be 
made into refined falt^ but will ferve to mix 
with the brine to be boiled up in the firft pro- 
cefs into common white fait. 

The fait refined after the foregoing pro- 
cefs will be exceeding ftrong and pure, and 
will have all the qualities required in fuch 
fait as is mofl proper for preferving fi(h, fleflij 
and other provilions. 

For firfl this fait will be extremely well 
depurated from all earthy alcaline fubflances, 
and from all the falts of the bittern, and all 
other mixtures of a different nature from it. 
So that in purity it will greatly exceed bay 


White Salt. 265 

fait, and even the Dutch refined fait, which 
they do not refine with pure river water, but 
with fca water, which abounds with calca- 
rious earth, and bitter falts, as hath before 
been demon fir ated. 

Secondly, the fait thus prepared will 
be extremely flrong, and fully fatiated with 
its acid fpirit. For the white fait propofed to 
be thus refim^d, is a flronger kind than any now 
commonly made. But fliould a much weaker 
kind be ufed, which had been deprived of 
a coniiderable quantity of its acid fpirit, even 
from this weak fait a flrong pure fait m.ay be 
prepared after the manner propofed in the 
feccnd procefs. For the faline particles de- 
prived of their acid, as they are not a per- 
fect muriatic fait, cannot therefore form into 
cubic cryflais, but will ei<:her lublide in the 
brine, in a white powder, or elfe, after the 
procefs is finiflied, will remain in the mother 
brine or bittern in the form of an alcaline 
fait ; fo that only the flrong pure cryflais of 
fait will be reduced into a folid form in 
the fecond procefs ; but in the fecond pro- 
cefs, here recommended, care is taken a- 
gain to reflore to thofe alcaline particles, 
the acid fpirit of which they had be- 
fore been deprived, and witii it to convert 




1 \ 

'266 ^he art of pj-eparmg 

them into a perfed: muriatic fait. And the 
heat wherewith it is propofed to evaporate 
tliQ water from the brine, being mild and 
well regulated, none of the acid fpirit will 
again be wailed. The fait therefore refined 
according to the method here propofed, may 
well be eftcemed a purer and flronger fait 
than that refined by the Hollanders, and at 
leall equally excellent for preferving provifi- 
ons. So that it will fully anfwer all the re- 
quifites in the foregoing problem. 

As to thofe additions which many recom- 
mend in order to make the fait grain or cry- 
flallize better, and to render it of a firmer 
and harder texture, they feem in this procefs 
entirely fuperfluous, and would prove pre- 
judicial rather than ferviceable, by rendering 
the fait impure. For when the watery va- 
pours exhale from the brine, by a mild and 
gentle heat, the fait naturally forms into 
' large hard cryflals without any addition, as 

I may be obferved in the preparation of bay 

In the above procefs for refining white 
fait, the moft exad: methods are defcribed -, 

II although in pradice fuch great accuracy may 
probably not be required : So that inflead 
of the ilrong white fait prepared according 



White Salt. 267 

to the firfl procefs, a weaker kind, boiled 
with more violent fires, may probably be 
fubflituted without any damage ; and in- 
flead of pure river water propofed in the fe- 
cond procefs for difiblving the fait, fea water 
may be fubftituted, agreeably to the pradlice 
of the Dutch, and then a confiderable part 
of the expence will be fwed. There are 
even fome kinds of natural brine fo free from 
Scratch, bitter falts, and other impurities, 
that, after they are depurated from their fedi- 
ment, and properly clarified, may probably, 
by the method propofed in thefecond procefs, 
be reduced into a pure flrong lalt, fit to be 
ufed as a condiment without undergoing the 
previous operation of boiling into white fait ; 
fuch, probably, may be the excellent brine of 

And although the brine of Chefhire, and 
alfo the rock fait of that county, contain 
much fcratch and other impurities, infomuch 
that the Dutch have found by experience, 
that the latter cannot, by their method, be 
refined into fo fi;rong and pure a fait, as that 
which they prepare from marine bay fait ; 
yet there is great reafon to believe, that, if 
the muriatic fpirit before recommended be 


268 ^^ ^^^ of preparing 

rightly applied and other proper means be 
iifed, a ftrong and pure white fait may be 
prepared, at one procefs, not only from 
Engliih rock fait, and moil kinds of Engliflu 
brine, but alfo from fea water, which will 
be very fit for curing provifions, in all the 
different ways, and for all ufes. For fo great 
is the efficacy of this fpirit, that by a proper 
mixture thereof, even common white fait may, 
in cafes of neceffity, be made to ferve for curing 
beef for long voyages ; as I have reafon to 
conclude from my own experiments, as 
well as from others, with which I have been 
made acquainted. 


In federal parts cf Great Britain , white fali 
might be refined by the foregoing method, 
at a fmall expcnce, and in any quantity 

It is a happinefs to Great Britain to be 
furrounded with feas, which, befides other 
advantages drawn from them, may be made 
to yield an inexhauilible ftore of fait. This 
illand likewife abounds in rock fait, and na^ 
tural brine j from all which refined fait may 


White Salt. 28^ 

be prepared in any quantities that can poffi- 
bly be wanted, either for home confump- 
tion, or for exportation abroad. 

Moreover, it is a bleffing peculiar to 
this ifland, to have vaft mines of fofiil coal 
in many places, nigh the fea, and nigh fait 
fprings and mines of rock fait ; with which 
coal, fait might be refined much cheaper 
here than in moft other countries. 

In many parts of Great Britain, as at 
Shields, pit-coals are fo cheap, that fait 
boiled with them from fea water, can be 
afforded at fo fmall a price as eight pence 
per bufhel ; and might, no doubt, be 
afforded at fuch places, for half the money, 
if, inffead of boiling fea water into fait, 
they ufed the fame water firff heightened 
into brine by the fun and air, after the me- 
thod here propofed ; and if, inftead of pans 
holding about 1800 gallons, they ufed pans 
like thofe of the Dutch, holding nigh ten 
times that quantity. 

The fait boilers at Lemington who 
heighten fea water into brine (by a method 
not the mofi: commodious) ufe chiefly New- 
caftle coals in boiling their fait, and pay five 
or fix times the price for them that is paid 
at Newcaflle or Shields. But in making a 


I \ 


s/o ^he art of preparing 

certain quantity of fait, they only evaporate 
one gallon of water by fire, for eight or ten 
gallons evaporated by the fait boilers at 
Shields 3 and with a pan of the fame mag- 
nitude, and the fame quantity of coals ufed 
at Shields, can make at leail five or fix 
times the quantity of fait that is made at 
the latter place ; by which means they are 
able to fell their fait at the London market, 
even cheaper than the fait boilers of Shields. 
From whence appears the great profit of 
heightening the fea water into brine, by the 
force of the fun and air. 

The great advantage of ufing large pans 
like thofe of the Dutch will alfo appear, by 
confidering, that a large furnace will require 
lefs fuel in proportion to its magnitude to 
heat it to a certain degree, than is required 
in a fmaller one ; and that two lobourers, 
who are now employed in working two fait 
pans of the common fize ufed at Shields, 
which hold each about 1800 gallons, will, 
with greater eafe, work a large pan, of the 
fize above propofed, holding about ten times 
that quantity^ fo that the price of labour 
and fuel (which are the articles of the 
greatefl expence) will be much lefs in the 


White Salt.' "271' 

larger work than in the fmaller, in proper- \ / 

tion to the quantity of fait made in each. '' 

The Dutch, in refining fait for the table, 
work out one of their large pans of brine 
every twenty-four hours j and if, from each 
gallon (wine meafure) of the brine ufed, 
two pounds and an half of fait be extrad- 
ed ; then, in a pan whofe bottom is forty 
feet fquare, and depth eighteen inches, they 
ufually make 801 bufhels of table fait every 
twenty- four hours ^ And the fame quan- 
tity of fait might be made from brine of 
equal strength, in an equal time, whether 
the brine be a folution of coarfe bay fait, as 
ufed by the Dutch, or fea water heightened 
by the fun, after the manner before propofed. 
But, as in the firfl procefs before defcribed, 
it is propofed to evaporate the brine with a i ,, 

very gentle heat, in order that the fait may 
be very flirong j we fhall therefore fuppofe 
only fix inches depth of brine to be eva- 
porated every twenty-four hours, and then 
the whole procefs will take up three days ; 

' Suppofing the pan ro be filled quire to the brim- 
but if the pan Ihould not be quite filled, they may not- 
Wichftanding nnake this quantity of fait every tvvenry- 
four hours, by ufing a fbronger brine thun here fup- 


^yi uke art cf preparing 

and fuch gentle fires will be applied, thaf 
probably not much more fuel will be con-^ 
fumed in thofe three days, than is confumed 
in the fame time, in boiling fea water with 
violent fires in the common Newcaflle fait 
pans, which hold about 1800 gallons. Al- 
though in the large pan 801 bufhels of 
flrong fait will be made in three days ; and 
only about 60 bufhels of a weaker fait in 
the fmall pan, by the method now in ufe, 
as I have been affured by very good judges. 
But if, in working the large pan, ac- 
cording to the method here propofed, it 
fhould be granted, that even twice as many 
coals were confumed as would work a New- 
caftle fait pan of the ordinary fize, with 
violent fires, which is certainly a very large 
allowance 5 then, as many coals would be 
confumed in three days, in working the 
large pan, as would make 120 bufhels, or 
three tuns of fait, according to the method 
now praftifed about Newcallle. And, al- 
lowing three chaldrons of coals to make a 
tun of fait, after the method there practifed, 
agreeable to the eflimates of fome of their 
mofl experienced fait boilers ; then nine 
chaldrons of coals (which at Newcaflle are* 
fold for 2I. 9 s. 6d.) would, by the method 


Wh I t e S a lt. '273 

here propofed make from brine 801 bufhels 
or twenty tuns of fait. So that the expence 
of coals (where they can be had fo cheap as 
at Newcaflle) would not exceed 2S. 6d. for 
every tun of fait thus prepared. Although, 
in making white fait after the common me- 
thods, fuel is the mofl: expenfive article ; 
and at Newcaftle, where coals are fo cheap, 
cofts above half the price of the fait prepared 
with it. 

The fame calculations alfo fliew the ex- 
traordinary advantages of making white fait 
from natural brine, or rock fait in large 
pans, according to the method here pro= 

But if fea water be boiled down to white 
fait without any previous preparation, after 
the method before propofed 3 then, in a 
large fquare pan, fuch as is dire«5ted for that 
ufe, 65828 gallons of water will be evapo- 
rated at each procefs, from which may be 
obtained 22^ bufliels of fait, allowing a 
pound of fait to be extracted from forty 
pints of the water. 

I AM very far from impoling the above 

calculations upon the public for fuch as will 

be found exactly true in practice j being fen- 

fible that true eftimates of the expence of 

T preparing 


274 Tl^^ art of pi'eparing 

preparing white fait by the methods here 
propofed, can only be made from proper 
experiments. Although thefe calculations 
fufficiently prove, that a fl;rong white fait 
may be made by the propofed methods 
confiderably cheaper, than a weaker fait is 
made by the methods now in ufe ; and very 
probably might be afforded for half the 
price for which white fait is now ufually 

If this fhould be found true by experi- 
ence ; then, as it would probably cofl tittle 
more to refine the white fait than to make 
it from brine or fea water ^ white fait re- 
fined after the method before diredcd might 
therefore probably be afforded for the fame 
price now ufually paid for common white 
fait, viz. from fix pence to ten pence per 

But as it may be neceffary to fet this 
matter in a clearer light j let it be fuppofed 
that the white fait, ufed in refining, cofls 
eight pence per bufhel, which is about the 
wholefale price of the fait made at Shields. 
In this eight pence is therefore included the 
price of coals, labour, a proper confidera- 
tion for the houfes, veffels, aud other uten- 
fils employed in preparing this buflicl of 


White Salt. 275 

fait ; and alfo the profit of the owner of 
the work. But, as it is found by experience, 
that forty pounds of fea water is commonly 
evaporated for each pound of fait obtained, 
therefore in making a bufliel or fifty-fix 
pounds of fait 56X40^=2240 pounds, or 
about 280 gallons of water may be fuppofed 
to be evaporated. But 280 gallons of water 
will very well diiTolve twelve bufhels of 
fait, allowing lefs than two pounds and an 
half of fait to a gallon of water. So that 
twelve bufhels of fait may be refined, by 
Waporating the fame quantity of water that 
is commonly evaporated in boiling onebufhel 
of fait from fea water. And if a proper 
apparatus be ufed, fuch as before defcribed, 
the expence of evaporating this quantity of 
water from the refined fait, will not proba- 
bly exceed the expence of evaporating it 
from the boiled fait, according to the pre- 
fent method. But allowing the expence of 
evaporating the faid quantity of water from 
the refined fait, to be treble the expence of 
evaporating it from the common boiled fait ; 
allowing alfo the drofs and impurities of 
the boiled fait, together with that which is 
loft of it in refining, to be a twelfth part of 
tlie whole j fo that from twelve bufli^ls of 
-T 2 the 



276 ^^ ^^'^ of preparing 

the common boiled fait, only eleven bu/hels 

of refined fait can be obtained j then the 

price of eleven bufhels of refined fait will 

be as follows : 

1. s. d. 

To twelve bufhels of common? 
white fait at 8d. per bufliel J 

To the expence of evaporating 
280 gallons of water, and 
other expences of refining the 
faid fait ; being treble the ex- 
pences of evaporating the fame I 
quantity of water, and of the 
other expences attending the 
preparation of a bufliel of 
white fea fait, after the com- 
mon method 

So that 1 1 bufhels of refined fait 
will cofl 



Which is nearly eleven pence per bufhel, 
and the expence of refining will be fome- 
what lefs than three pence per builiel. 

But if, inflead of fea fait, boiled rock 
fait, or brine fait be ufed, which can now be 
afforded in Chefhire for fix pence per bufh- 
el 5 then the eftimate will fland thus : 


White Salt. 277 

1. s. d. 

6 o 

To 12 bufliels of boiled rock, or| 
brine fait i 

Charges of refining 020 

And the price of eleven bufliels of ^ „ 

refined fait will be j 

Which is Sd.vTj or nearly 8d.^ per 


But if white fait prepared by the me- 
thod recommended under propofition the 
firft be ufcd, which in feveral parts of Great 
Britain may probably be afforded for four 
pence per bufhel j then, according to the 
above eftimates, the refined fait will cofi: the 
refiner about fix pence halfpenny per bufliel, 
who may therefore very well afford to fell 
it for eight pence per bufliel. 

The following eftimate brings the matter 
a little nearer to pradiice, and therefore to 
fome may feem more clear and fatisfadory 
than the foregoing. 

The Dutch fait pan of a cylindrical form, 
forty feet in diameter, and eighteen inches 
deep, will contain 14106 gallons, wine mea- 
fure. Suppofing therefore, that into a pan 
ofthatfize 14000 gallons of brine be pour- 
ed, of fuch a ffrength, that from each gal- 


2yB 7'he art of preparing 

Ion two pounds and an half averdupoize of 
fait may be extracted. From the whole 
14600 gallons of brine, then may be ex- 
tracted 35000 pounds or 625 bufhels of 
fait. So that 625 bufliels of refined fait 
may eafiiy be prepared in fuch a pan in fix 
days (the Dutch perform this operation in 
three days) allowing only three inches depth 
of water to exhale every twenty-four hours. 
And if the whole procefs be confideced, the 
labour and attendance required in working 
fuch a pan will not appear greater, than is 
required in working a common Newcaftle 
pan, in boiling fea water into fait. And, 
as very flrong fires are ufed in boiling fea 
water, as many coals will probably be con- 
fumed in keeping fuch a common pan con- 
ftantly at work, as in keeping the brine in 
the large Dutch pan of a mild and tempe- 
rate heat. It therefore feems highly proba- 
ble, that the expence of fuel and labour 
will be as great in working a common pan 
in boiling fea fait, as in working a pan of 
the above dimenfions in refining fait. 

But in a common pan about 120 bufli- 
els of fait may be boiled from fea water in 
fix days, the price of which at eight pence 
per bufhel is four pounds j in which four 


White Salt. 279 

pounds is not only included the price of 
labour and coals, but alio a proper allow- 
ance for the wear of veffels and utenlils, 
and for all other contingent expences, toge- 
ther with the profit of the owner of the 
work. But fuppofing the expence of la- 
bour and fires only, in the propofed work 
for refining fait, to amount in fix days to 
four pounds ; and allowing three pounds 
more for the wear of vefiels and utenfils, and 
other contingent expences, and the refiners 
profit ; and alfo eighteen fliillings more for 
fifty-four bufliels of white fait, which may 
be fuppofed to be wafi:ed in the procefs. 
Then the whole expence of the work for 
fix days (the profit of the owner included) 
will amount to {even pounds eighteen fliil- 
lings J which being charged upon 625 
buihels of fait, in that time refined, amounts 
to very little more than three pence per 

As in the above calculations large al- 
lowances are made in every article j it there- 
fore feems probable, that fait refined in the 
foregoing manner, may in feveral parts of 
Great Britain be afforded for fo fmall a 
price as eight pence per bulhel. But fliould 
we even fuppcfe the unrefined white fait to 

I coft 

28o ^je art of preparing 

coft eight pence per bufhel ; and Inftead of 
three pence per bufhel, the price of refining 
as before eftimated, fliould allow thrice that 
fum, or nine pence per bufliel for refining 
it ; then the price of a bufliel of this refined 
fait would be feventeen pence, which is lefs 
than the Dutch pay for their ftrong refined 
falti and is lefs than half the fum nov/ ufu- 
ally paid in London for bay fait, for curing 
provifions. For in times of peace, the beft 
bay fait commonly there cofls the confumer 
about ten fliillings per bufhel, weighing 
eighty-fix pounds -, and now, in time of war, 
eleven {hillings per bufhel j which, abil:rad:ed 
from the duty, is two fliillings and ten pence 
two thirds for fifty-fix pounds • the weight 
of a bufhel of white fait. So that if the 
Britifli refiner can afi^brd his fait at the mar- 
ket for lefs than two fliillings and ten pence 
two thirds per bufhel, large fums of money 
may be faved in the nation, which are now 
paid for foreign fait, and ferve to enrich 
our enemies and rivals in trade. 

All thefe calculations are made without 
any regard had to the fait duties ; upon a 
fuppofition that the fait is fold duty free, 
as that is which is exported abroad, or ufed 
in curing fifh for foreign confumption. But 


White Salt. 2^1 

if the duties, as now regulated by law, are 
alfo taken into confideration, the Britifh re- 
finer of white fait, hath greatly the advan- 
tage over the importer of foreign fait, as 
will appear from the accounts already given 
of the duties upon each. 

From all the above-mentioned fails and 
reafonings we may therefore conclude, that 
white lalt refined after the foreffoine me- 
thod, (probably better in quality, and fitter 
for the ufe of the fifheries, and for curing 
all kinds of provisions, than French, and 
other impure kinds of bay fait) might eafily 
be prepared in Great Britain, in any quan- 
tity wanted, and might be there afforded 
conliderably cheaper than foreign bay fait ; 
fo that the money paid to foreigners for fait 
might eafily be faved in the kingdom, and 
great advantages might arife from ufing this 
fait (or pure bay fait prepared as before di- 
reded) in the Britifh fi(l:ieries ; and by means 
thereof, the Britilh colonies in the Wefl In- 
dies, and the navies and commerce of Great 
Britain, might be put out of a flate of de- 
pendance upon its enemies for one of thofe 
iiecefTaries without which they cannot pofli- 
bly fubfifl. 

U A ^^ ^- 

282 ^he art of preparing 

AND now it may be proper to conclu(^€ 
this treatife with obferving, that mofl of the 
fads referred to in the courfe of thefe dif- 
quifitions, are fuch, as the conftant pradtife 
of thofe who make fait fufficiently warrants 
us to rely upon for true and certain ; or elfe, 
they are the obfervations of judicious fait 
officers, daily converfant in thefe matters; 
or, of curious and inquifitive navigators, 
merchants, travellers, and naturalilfs ; or 
laftly, the experiments of many learned 
phyiicians, chemifts, and philofophers ; the 
truth of which feveral fads, though many 
of them have long been publilhed, hath 
never to my knov/ledge been called in que- 
fiion. So that thefe obfervations and expe- 
riments may probably be more relied upon 
by the public, than if they had only been 
made by myfelf ; lince they have the tefli- 
mony of many fkilful and unprejudiced per- 
fons,who could liave no notion of the ufes to 
which they have been here applied. If there- 
fore the arguments founded upon thofe fads 
fliould be elieemed any ways reafonable and 
fatisfadory, I humbly prefume to remark, 
that it might not be unworthy the wifdom 
of the Britifh legiilature to dired a more full 
innuirv to be made into a matter of this im- 

White Salt* 283 

portance ; and to order proper works to be 
ered;ed for making bay ialt, and for making 
and refining wliite fait ; and to put thofe 
works under the management of able and 
judicious perfons, to make exa6t and ac- 
curate tryals, in order to difcover the befl 
and cheapeft methods of making bay falt^ 
and of making and refining all kinds of 
white fait. And the methods which iliould 
be moft approved of, might for the general 
good, be made public, and eflablifhed by 
law, as a common ftandard, to which all 
thofe who make fait in the Britifli do- 
minions fhould be obliged to conform. And 
it would be the interefl of the proprietors 
of fait works ftridily to comply with the 
rules fo eflabliflied j but if they fhould neg- 
lect them, the exaO: obfervance of them 
might, with the greatefl eafe be enforced ; 
fincc his Majefty hath officers who conflantly 
attend at all fait works, who are commonly 
well {killed in the bufinefs of making fait, 
and might eafily be made acquainted with 
the rules eftablifhed, and with the qualities 
required in the fevcral kinds of fait, and 
might have orders to infpedl over the prepa- 
ration of fait, and to receive none into the 
king's warehoufes, but fuch as was fit for 

U 2 fale. 

284 thf art of preparing &c. 
iile, and duly prepared according to the 
ftatute ; and might have power to feize, and 
(with the aid of the civil magiftrate) to con- 
clemn and deftroy all fait not rightly pre- 
pared, or at leaft to take care, that it was 
only applied to the improvement of land, 
and fuch hke purpofes. Such an eftablidi- 
ment would put it out of the power of any 
one to impole had fait upon the publick, as 
is now too frequently done, in a moft fcan- 
lous manner, to the great damage of thofe 
who ufe fuch bad fait for curing provifions, 
and to the great prejudice of the health of 
many of his Majcfty'sfubjeas, who are often 
obliged to live upon provilions thus fadly 
cured.^ By fuch an eftablifliment alfo, the 
fait officers might be made to do a very con- 
fiderable benefit to the nation, with little ad- 
ditional trouble to thcmfelves, and his ma- 
jefty's fubjcds would have reafon to efteem 
the duties upon fait lefs burthenfome than 
at prefent, if by this means they were aflured 
of being conftanriy fupplied with fuch fait 
as was moft fit and proper for the feveral 
purpofes for which it was defigned. 






Explanation of the Plates. 

p L A T E I. 

AAA. Is the fea. 

1 I. The entry, by which the fea- water 
pafTes into B B. 

B B. The firft receptacle ; in which the wa- 
ter is kept twenty inches deep. 

C C C. The fecond receptacle, where the 
water maketh three turnings, as you fee, 
and is ten inches deep. 

* * The place, where the communication 
between the firft and fecond receptacle is 
made in the French fait marfh, but here 
more conveniently removed to 2 2. 

2 2. The opening, by which the firft and 
fecond receptacle have communication 
one with another. 

E E F. The third receptacle, which is pro- 
perly called the Mariih. 

dddddd. Is a channel very narrow, through 
which the water muft pafs before it enters 
out of the fecond receptacle into the third. 

U 3 33« 

2^6 Explanation of the Plates. 

3 3. Is the opening, by which the water runs 
out of the fecond into the third receptacle. 

The priclcs, yon fee in the water throughout 
the whole fcheme, mark the courfe and 
turnings, which the water is forced to 
make before it comes lo hhhhh, which 
are the places where the fait is made. 

hhhhh. Are the beds of the marifh, where 
the fait is made; and in them the water 
muft not be above an inch and an half 
deep. Each of thefe beds is fifteen feet 
long and fourteen feet large. 

99999. Are the little channels between the 

88888. Are the apertures, by which the beds 
receive the fea-watcr after many windings 
*nd turnings. 



Explanation of the Platen. 287 

P L A T E II. 

Fig. I. Being a reprefentation of a marine 
faltern, with two boiling houfes, and the 
forehoufe in the middle between them. 

a a a. L'oeuvres for the vapours which arife 
from the fait pan. 

b b. Windows in the roof. 

c c. Chimnies for the fmoke of the furnaces. 

P. Roof of tile or flate over the forehoufe. 

Q^^Q^Roofs of boards over the boiling houfes. 

Fig. II. A fedion of the fald faltern made 

lengthways ; together with a fe6lion of 

a fhed placed at the end of it with a ciftern 

for the fea-water. 
a a. L'oeuvres at the top of the boiling houfes 

for the fteam. 
cc. "The chimnies. 
dd. The fait pans. 

€ e. Walks at the end of each fait pan. 
ff. The furnaces under the fait pans. 
g g. The afh pits. 
hh. The wood ciflern for the fait- water, 

which is from it conveyed through pipes 

into the fait pans. 
j. The pump, by which the fait water is 

raifed into the ciflern, from 

U 4 k. The 




;i ^- ^ .^ 

?88 Explanation of the Plates. 

k. The well, funk confiderably deeper than 
the bottom of the faltern to the level of 
the fea at half flood. 

//. The partition walls between the fore- 
houfe and the boiling houfes, 

mm. Solid beds of earth. 

». The flues of the furnaces. 

N. B. The pricked lines in the middle of 
the forehoufe (hew the fituation of the 
door, from which there is a defcent by an 
inclined plane to the bottom of the faltern. 


¥■' ' 


B>^p^anaUon of the Plates, 289 


Fig. I. A crofs fedion of the marine faltern 

exhibiting the front of the furnace. 
a a. The doors of the two chambers of the 

^ If, The afh pits. 
cc The partition wall dividing the fore- 

houfe from the boiling houfe. 
ddd. K brick arch which fupports the parti- 

tition wall when it is neceifary to take away 

the lower part and repair the furnace. 
e e. Stairs leading to the boiling houfe. 
f. Door of the boiling houfe. 
gg. Out walls and roof of the building, 
f'ig. II. A crofs fed:ion of the furnace and 

fait pan. 
A. The fait pan. 
O. A crofs beam of iron which ferves to 

fupport the bottom of the pan by means 

of clafps and hooks. 
B B. The two chambers of the furnace. 
C C. The afh pits. 
M. The mid-feather, dividing the body of 

the furnace into two chambers. 
ff. The grates in which are feen the long 

bars of iron, and below them the crofs 


FU/^ JP 


290 Explanatioi: of the Plata. 

bars or bearers, by which the others are 

gg. Pillars of caft iron called taplins which 

fupport the fait pan. 
jj. Walks on the fides of the pan, that on 

the fide next the door to which they 

draw the fait being broader than the walk 

on the other fide. 
II. Beds of folid earth. 
nn. The out walls of the faltern. 



t-^ Sai/t trfjimr £/<<•/' /V> art, ,%ic/l > . 

Explanation of the Plates, 2gi 


Fig. I. A plan of the bottom of the furnace 

with the grates, flues, &c. 
ff. The grates as in the preceding figure. 
D D. The flues from which the fmoke 

pafl"es into the chimney. 
e. The entrance into the chimney. 
h h. The two mouths of the furnace, 
m. The mid-feather. 
kkkk. Thefe pricked lines fhew the dimen- 

fions of the bottom of the fait pan. 
Fig. II. A fedion of the furnace made length 

N. B. The letters fhew the fame parts of 

the work as in the preceding fedions. viz. 

A. The fait pan. 

0, The iron beams which fupport its bot- 

B. A chamber of the furnace. 

C. One of the afh pits. 

D. One of the flues. 
e. The chimney. 

/. The grate. ^ 
h: A mouth of the furnace with 
k. Its door. 

j. Walk at the end of the fait pan, 
/, Bedoffolid earth, 


92Z Explanation of the P/atei. 

n n. The partition wall and walls of the 

hi. B. The figures in this and the forego- 
ing plate are all made by one fcale, which 
is given at the bottom of this plate. 



Explanation of the Plates, 295 


From Agricola, De re met alii ca. Lib. xii. 

Fig. L Four polls of wood fixed perpendi- 
cular in the earth -, on which are ereded 
two end beams, and feveral crofs beams, 
from which hang down hooks, fupport- 
ing the bottom of the fait pan when fixed 
thereto by clafps. Thefe are ftill ufedin 
Germany ; as they were lately at feveral 
falterns in England. 

Fig. 11. A fait pan of iron plates with clafps 
fixed to its bottom. 

Fig. III. The fame falt-pan placed over the 
furnace, and fupported by the wood beams, 
with the operators taking out the fait into 
baflcets, which in this work are hung up 
againft the wall. 

N. B. In thefe works there feems to have 
been no wall between the forehoufe and 
boiling houfe ; and the fait pan feems to 
have been expofed to the duft and fmoke 
of the furnace ; fo that when they ufed 
ftraw for fuel, its light aflies flying about 
made the fait black. ' 


294 Expldi2atio7t of the PlaUS^ 

P L A T E VI. 

Fig. I. The fait pans formerly ufed in 
Chefhire four to a furnace j together with 
their furnace, and the hot houfe or ftove 
behind them. From the Ads of the Royal 
Society. In which, 

aaaa. The hothoufe between the wall and 
the chimney. 

h b. Two tunnels. 

C C. The chimney back into which the 
tunnels convey the fmoke. 

dddd. The four pans. 

E. The partition wall between the pans and 

the hot- houfe. 
ff. The fire-places. 

gg. The afh-holes. 

b. The hearth below. 

i. The defcent to the hearth. 

Fig 2. Two wicker bafkets or barrows filled 
with fait and placed over the leach trough, 
as pradiifed at the Chefliire fait works j 
From the faid ad:s. 

Fig: 3. A fkimmer made of boards, more 
commodious than the Chefliire loot, or 
any other inflrument yet invented for 
flvlmming the brine. 

Fig. 4. The Dutch wooden rake, its han- 
I die 

Explanation of the Plates. 295 
die twenty feet long, being preferable to 
the iron rakes commonly ufed for draw- 
ing the fait, as they are apt to contrail 

Fig. 5. A wood (hovel, to take the fait out 
of the pan after it is drawn to one fide with 
the rake. 

Fig. 6. An iron ladle to take out the bit- 



Pag. Not. Lin; 

34 7 z for than at * where read at 2 . 2 . where 
43 ' " " 7 J°^ ^'^^ ^xam. read from 

48 - - - 2 /or ponds r^^^ wells 

51 - - 2 yor each of which r^«i beneath each of which 

53 10 /orPIateV.Fig. 2.r^a</PlateV. Fig. 1 and 2. 
56 - - 3 yor back fide of the forefide of the fore houfe 

read back fide of the fore houfe 
61 17 10 yJr better r^ai bitter 

84 14 7 r^/?</ Bofphorus of Thrace 

54 14 10 for Riv. rfa<^ Rio 

85 - ~ ^for-i^jZ read-i^;^ 
85 - - nfor-ijl read ^-r, J 

87 - - 1 7 for draughts read droughts 

90 22 4 y9r putrify r^a^ purify 

96 - - i^ for kind read kinds 

129 - • ^ for its rfa/^ the 

149 - - 1 for For from rfi2</ From 

158 1 I for a whole read a whole day 

1 82 - - 7 /or As to read As 

191 - - 24yorpwts. rf«^ grains 

1 92 3 4 for -ijt I '■^«</ 2 * : I 
205 - - 1 yor brine pits read brine ponds 
205 - - 4 /S'' fait ponds read ponds 
205 - - 1 1 yor pits read ponds 

209 -- 2 1 /er water contained 7 • C brine contained in 

in the brine £ ^ i.the fait pits 

217 - - 2"] for draughts r^a</ droughts 

224 4 ^ for this off read flies off 

250 - - 12 for no read not 

257 - - 22 for the moft read in moft 

267 - - 6 for agreeably read agreeable 

284 -- i5/5rfadly r^a^ badly