SAL 
S A L 
SAL 
f ) ! 5 
the class and order pentandria ctigynia, and 
in the natural method ranking under the 12th 
order, holoraceaj. The calyx is pentaphyl- 
lous ; there is no corolla ; the capsule is mo- 
nospernious, with a screwed seed, i he spe- 
cies are 31, of which the principal are: 
1. Salsoia kali grows naturally in the salt 
marshes in divers parts of England. It is an 
annual plant, which rises above five or six 
inches high, sending out many side branches, 
which spread on every side, with short awl- 
shaped leaves, which are fleshy, and ter- 
minate in acute spines. 
2. Salsoia rosacea grows naturally in Tar- 
tary. This is an annual plant, whose stalks 
are herbaceous, and seldom rise more than 
five or six inches high. 
3. Salsoia soda rises with herbaceous stalks 
near three feet high, spreading wide. 4 he 
leaves on the principal stalk, and those on 
the lower part of the branches, are long, 
slender, and have no spines; those on the 
upper part of the stalk and branches are 
slender, short, and crooked. All the sorts of 
glass-wort are sometimes promiscuously used 
for making soda or mineral alkali, but this 
species is esteemed best. The manner of 
making it is as follows: Having dug a trench 
near the sea, they place laths across it, on 
which they lay the herbs in heaps, and, hav- 
ing made a fire below, the liquor which runs 
out of the herbs drops to the bottom, which 
at length thickening, becomes soda, which is 
partly of a black, and partly of an ash-colour, 
very sharp and corrosive, and of a saltish 
taste. This, when thoroughly hardened, be- 
comes like a stone, and in that state is trans- 
ported to different countries for the making 
of glass, soap, & c. 
4. Salsoia tragus grows naturally on the 
sandy shores of tiie south of I ranee, Spain, 
and Italy. This is also an annual plant, 
which sends out many diffused stalks, with 
linear leaves an inch long, ending with sharp 
spines. 
5. Salsoia vermiculata grows naturally in 
Spain. This has shrubby perennial stalky 
which rise three or four' feet high, sending 
out many side branches, with fleshy, oval, 
acute-pointed leaves, coming out in clusters 
from the side of the branches ; they are hoary, 
and have stiff prickles See Soda. 
SALT, common. The preparation of that 
kind of salt which is used for culinary and 
economical purposes (muriat of soda) de- 
pends upon tiie well-known fact, that the salt 
contained in the sea-water, or brine-springs, 
being a fixed body, will not rise with the va- 
pour of the water. All, therefore, that is 
wanted, is to expose any water containing 
•salt to evaporation. The salt commonly 
known by the name of bay-salt is obtained 
from the "water of the sea by evaporation. 
This evaporation is in some places performed 
by the heat of the sun, the water being let 
into shallow trenches, in order to expose as 
large a surface as possible. This method is 
practised in the southern provinces of France, 
and on a very large scale near Aveiro in Por- 
tirral. In the northern countries, where the 
beat of the sun is not sufficiently great, arti- 
ficial (ires are employed. In some salt-works 
these two methods are united ; and in Eng- 
land, and countries where salt-rock is plen- 
tiful, that substance is dissolved in salt water, 
and then evaporated. In very cold countries 
another method is employed to separate the 
salt from sea-water. The water is exposed 
in trenches on the sea-shore, where it forms 
so thin a stratum, that the cold of the atmo- 
sphere acts powerfully in congealing it. As 
the frozen part consists of mere water, the 
fluid which remains is consequently more 
concentrated. The operation is then com- 
pleted by means of artificial heat. 
The most convenient works for making salt 
from brine by boiling are constructed in the 
following manner: The saltern, or boiling- 
house, is erected near the sea-shore, and is 
furnished with a furnace and one or two large 
pans, which are commonly made of iron 
plates, joined together with nails, and the 
joints filled with a strong cement ; and the 
bottom of the pans is. prevented from bend- 
ing down, by being supported by strong iron 
bars. 
The salt-pan being filled with sea-water, a 
strong tire of pit-coal is lighted in the fur- 
nace ; and then, for a pan which contains 
about 1400 gallons, the salt-boiler takes the 
whites of three eggs, and incorporates them 
all with two or three gallons of sea-water, 
which he pours into the salt-pan, while the 
water contained therein is only lukewarm, 
and mixes this with the rest by stirring it 
about with a rake. In many places they 
use, instead of eggs, the blood of sheep or 
oxen to clarify the sea-water : and in Scot- 
land they do not give themselves the trouble 
to clarify it at all. As the water heats, there 
arises a black frothy scum upon it, which is 
to be taken off with wooden skimmers. Alter 
this the water appears perfectly clear, and by 
boiling it briskly about four hours, a pan 
loaded in the common way, that is, about 
fifteen inches deep, will begin to form crys- 
tals upon its surface. The pan is then filled 
up a second time with fresh sea-Water; and 
about the time when it is half-filled, the 
scratch-pans are taken out and emptied of a 
white powder, seeming a kind of calcareous 
earth, which separates itself from the sea- 
water, during its boiling, before the salt be- 
gins to shoot. When these have been emp- 
tied, they are again put into their places, 
where they are afterwards filled again. This 
powder being violently agitated by the boil- 
ing liquor, does not subside till it comes to 
the corners of the pan, where the motion of 
the mass is smaller, and it there falls into 
these pans placed on purpose to receive it. 
The second filling of the pan is boiled 
down after clarifying in the same manner as 
the first, and so a third and a fourth ; but in 
the evaporation of the fourth, when the crys- 
tals begin to form themselves, they slacken 
the fire", and only keep the liquor simmering. 
In this heat they keep it all the while that 
the salt is granulating, which is nine or ten 
hours. The granules, or crystals, all fall to 
the bottom of the pan ; and when the water 
is almost all evaporated, and the salt lies 
nearly dry at the bottom, they rake it all toge- 
ther into a long heap on one side of the pan, 
where it lies a while to drain from the brine, 
and then is put into barrows, and carried to 
the storehouse, and delivered into the cus- 
tody of his majesty’s officers. In this man- 
ner the whole process is usually performed 
in 24 hours, the salt being commonly drawn 
out every morning. This is the method in 
most of our salt-works; but in some they, 
fill the pan seven times before they boil up 
the salt, and so take it oui but once in two 
days, or five- times in a fortnight. In the 
common way of four boilings, from a pan of 
the usual size, containing 1300 gallons, they 
draw from fifteen to twenty bushels of salt 
every day, each bushel weighing fifty-six 
pounds. 
When the salt is carried into the store- 
house, it is put into brabs, which are parti- 
tions, like stalls for horses, lined at three 
sides, and the bottom with boards, and having 
a sliding-board on the foreside to draw up on 
occasion. The bottoms are made shelving, 
being highest at the back, and gradually in- 
clining forward ; by this means the brine re- 
maining among the salt, easily separates and 
runs from it, and the salt in three or four 
days becomes sufficiently dry ; in some places 
they use cribs and barrows, which are long 
and conic wicker-baskets, for this purpose ; 
and in some places wooden troughs, with 
holes in the bottom. The saline liquor 
which remains from the making of salt is 
what is called bittern, from which Epsom salt 
or muriat of magnesia is often extracted. 
Much in the same manner is the salt ob- 
tained from the brine of salt-springs, pits, &c. 
White salt is prepared from sea-water, or any 
other kind of salt-water, first heightened into 
a strong brine by the heat of the sun, and the 
operation of the air. It may also be pre- 
pared from a strong brine, or lixivium, drawn 
from earths, stones, or sands, strongly im- 
pregnated with common salt, llefmed rock- 
salt is that obtained by dissolving fossil or 
rock-salt in salt or fresh water, and afterwards 
boiling the solution. 
A great quantity of rock-salt is used at 
Northwich, in order to strengthen their brine- 
springs; and a much greater quantity is sent 
coastwise to Liverpool, and other places, 
where it is either used for strengthening 
brine-springs or sea-water; much of this 
rock-salt was formerly exported to Holland, 
; and it is still sent to Ireland for the same 
I purpose. 
4 he Northwich rock-salt is never used at 
our tables in its crude state ; and its applica- 
tion to the pickling or curing of flesh or fish, 
or preserving any provisions, without its beinti 
previously refined into white salt, that is,- 
without its being dissolved in water, and boil-- 
i ed down in v liat is called white-salt, is prohi- 
| bited under a penalty of 40, y. for every pound 
I ol rock-salt so applied. The pure transpa- 
| rent masses, however, of rock-salt, might pro- 
| bably be used by us with our food, without 
I any sort of danger or inconvenience ; at 
i least we know that rock-salt is so used, with- 
I out being refined, both in Poland and in. 
! Spain. 
i The quantity of rock-salt which may be 
dissolved in a definite quantity, suppose a 
pint of 16 avoirdupois ounces of water, is 
differently estimated by different authors. 
Bcerhaave is of opinion that 16 ounces of 
water will not dissolve quite five ounces of 
rock-salt ; Spielmann thinks that they will 
dissolve 6J ounces; Newman agrees" with 
Spielman y Eller says, that seven ounces 
of fossil salt may be dissolved in 16 ounces 
of water; lastly, Hoffmann assures us, that 
16 ounces of water will not dissolve above six 
ounces of common salt. It is not wholly 
improbable, that different sorts of vock-sait' 
may differ somewhat with respect to their 
solubility in water. 
