U 'S A L 
^ * s admitted, that Hi ounces of water 
«-ui dissolve six ounce.-, of salt and no more, 
. lLil Wt ~ * na y ^ J c certain, that no brine-spring 
in any part yf q lc . world, can ^ i t *lcl six ounces 
*' Stlit lroni a pint of the brine. For brine 
WS«.aie, ordinarily, nothing but water in 
n nc.h fossil salt has. been dissolved ; l ut a 
P>nt Oi Uie strongest brine cannot contain so 
niuch salt as is contained in a pint of water, 
'.'inch nas been saturated with six ounces of 
^ ’ * ora P'nt of water, in which six ounces 
•> sad have been dissolved, is increased a 
'•die m bulk; it will do more than liil a pint- 
measure, and the salt left in the surplus will 
shew how much the salt contained in a pint 
o. the strongest brine falls short of six ounces. 
Or we may consider the matter in the fol- 
lowing manner, w hich will perhaps he more 
intelligible ; 16 ounces of water, impregnated 
with six ounces of salt, constitute a saturated 
brine, weighing 22 ounces ; if therefore we 
w ould know how much suit is contained in 
16 ounces of such brine, by the rule of pro- 
portion we may argue, that if 22 ounces of 
bi iue contain six ounces of salt, 16 ounces of 
brine will contain 4^±- ounces of salt. Hence 
w’e may infer, that the strongest brine-springs 
w ill not yi.eld much above one quarter of their 
weight of salt. 
i here are a great many brine-springs in 
■Cheshire, in Worcestershire, Staffordshire, 
Hampshire, and in other parts of Great Bri- 
tain ; some of which are sufficiently rich in 
salt to he wrought with profit, others not. 
From what has Ireen before advanced, the 
reader will readily comprehend that 16 tons 
of the strongest brine consist of 12 tons of 
water, and of four tons of salt ; and that, in 
order to obtain these four tons of salt, the 
12 tons of water must be, by some means or 
other, evaporated, so as to leave the salt in a 
concrete form. Suppose there should be a 
brine, which in 16 tons should contain 15 tons 
of water, and only one ton of salt ;,yet it may 
chance, that such a weak brine may be 
w rought with more profit than the strongest ; 
for the profit arising from the boiling of brine 
into salt, depends as much upon the price of 
the fuel used in boiling it, as upon the quan- 
tity of salt which it yields. Thus the sea- 
water, which surrounds the coasts of Great 
Britain, is said to hold seldom more than one- 
thirtieth, or less than one-fiftieth part of com- 
mon salt; but fuel is so cheap at Newcastle, 
that they can evaporate thirty or forty tons 
of water, in order to obtain one ton of salt, 
and yet gain as much clear profit as those do, 
who, in countries less favourably situated for 
fuel, boil down the strongest brine. 
The advantage resulting from strengthen- 
ing weak brine or sea-water, by means of 
rock-salt, is very, obvious. Suppose that the 
sea-water at Liverpool, where large quanti- 
ties of rock-salt are refined, would yield one 
ton of sa't from 48 tons of water ; then must a 
quantity of fuel sufficient to evaporate 47 tons 
of water be used, in order to obtain one ton 
of salt. Bet if as much rock-salt is put into 
the fort -eight tons of sea-water ; as can be 
dissolvecf in it, then will the sea-water re- 
semble a brine fully saturated, each Ifitons 
of which will give four tons of salt, and the 
whole quantity yielded by the evaporation 
of 47 tons of water wiil be 12 tons of salt, 
SALTS. The word salt was originally con- 
fined to munat of soda, or common salt, a 
S ‘A L 
substance which has been known, and in 
common used, from Inc remotest ages. It 
was allerwards generalized by chemists, and 
employed by them in a very extensive and 
not very definite sense. Every body which 
is sapid, easily melted, soluble in water, and 
not combustible, has been called a salt. 
Salts., were considered by the older che- 
mists as a class of bodies intermed ate be- 
tween earths and water. Many disputes 
arose about what bodies ought to be com- 
prehended under tins class, and what ought 
to be excluded from it. Acids and alkalies 
were allowed by all to be salts; but the diffi- 
culty was to determine eoncernir.g earths 
and metals; for several of the earths possess 
all the properties which have been ascribed 
to salts, and the metals are capable of enter- 
ing into combinations which possess saline 
properties. 
in process of time, however, the term salt 
was restricted to three classes ol bodies, viz. 
acids, alkalies, and the compounds which 
acids form with alkalies, earths, and metallic 
oxides. The first two of these classes were 
called simple salts; the salts belonging to the 
third class were called compound or neutral. 
This last appellation originated from an o,v- 
nion long entertained by chemists, that acids 
and alkalies, of which they are composed, 
were of a contrary nature, and that thev coun 
teracted one another; so that the resulting 
compounds possessed neither the properties 
of acids nor of alkalies, but properties inter- 
mediate between the two. 
Chemists have lately restricted the term 
salt still more, by tacitly excluding acids and 
alkalies from the class of salts altogether. At 
present, then, it denotes only the compounds 
formed h;j the combination of acids zvith al- 
kalies, earths, and metallic oxides. 
No part of chemistry has been cultivated 
with more zeal than the salts, especially for 
these last 40 years. During that time the 
number of saline bodies has been enormously 
increased, and the properties of a very great 
number have been determined with precision. 
Still, however, this wide and important re- 
gion is far from being completely explored. 
Chemists have agreed to denominate the 
salts from the acids which they contain. The 
earth, alkali, and metallic oxide, combined 
with that acid, is called the base of the salt. 
1 bus common salt being a compound of mu- 
riatic acid and soda, is called a muriat; and 
soda, is called the base of common salt. Now 
since there arc 32 acids and 57 bases, it would 
appear, at first sight, that there are 1824 
salts; but of the 45 metallic oxides at pre- 
sent known, there are a considerable number 
which cannot combine with many of the 
acids. This is the case also with silica, and 
perhaps with some of the other earths. We 
must therefore subtract ail these from the 
full number 1824. To compensate, however, 
this deficiency, at least in part, there are* se- 
veral acids capable of combining with two 
bases at once. Thus the tartaric acid com- 
bines at once with potass and soda. Such 
combinations are called triple salts* and they 
increase the number of salts considerably. 
There are some salts, too, which are capable 
of combining with an additional dose of their 
acid, and others which combine with an addi- 
tional dose of their base. The French che- 
mists denote the first of these combinations 
by adding to the usual name 'of the salt the 
SAL 
phrase witn excess of acid, or by prefixing ft 
to the word acidulous: they denote the se- 
cond by subjoining the phrase with excess of 
base, i his method of naming has the merit 
indeed of being precise, but ii is exceedingly 
awkward, and intolerably tedious. The in- 
genious mode of naming these combinations 
proposed by Dr. Pearson ought certainly to 
be preferred. It is equally precise, if not 
more so, and far more convenient in every 
respect, it consists in prefixing to the usual 
name of the salt tite preposition super, to de- 
note an excess of acid, and the preposition 
sub to denote an excess of base, i bus sul- 
pbat of potass di-motes the salt in its state of 
perfect neutralization, without anv excess 
either of the sulphuric acid or of the potass ; 
supersulphat of potass is the same salt with 
an excess of acid ; subsulphat of potass is the 
same salt with excess of base, i he»e three 
different kinds must increase the number of 
saline compounds very considerably; but the 
precise number of salts is not known, as many 
o: them remain still unexamined by che- 
mists. Probably they are not much fewer 
than 2000. Some idea may be formed of the 
progress which this branch* of chemistry has 
made, by recollecting that 40 ) ears ago not 
more than 30 salts in ail were know n. 
Of these 2000, however, a considerable 
number may be considered as still unknown, 
as they have been merely formed without 
being examined. Of those which are known, 
the greater number have not been applied to 
any use, and therefore do not deserve a very 
particular description. 
As the different genera of salts are denomi- 
nated from their acids, it is evident that 
there are as many genera as there are acids. 
I he terminations of the names of these ge- 
nera differ according to the nature of the 
acids which constitute them. When that acid 
contains a maximum of oxygen, the termina- 
tion of the genius is at; when it does not 
contain a maximum of oxygen, the termina- 
tion of the genus is ite. Thus the salts which 
contain sulphuric acid are called sulphats ; 
those which contain sulphurous acid are 
called sulphites. '] his distinction is of some 
consequence, because the salts differ very 
muefi, according as the acid is saturated w ith 
oxygen or not. '1 he ites are seldom perma- 
nent ; when exposed to the air, they usually 
attract oxygen, and are converted into ats. 
Every particular species of salt is distin- 
guished by subjoining to the generic term 
Lite name of its base, J Inis the salt composed 
ot sulphuric acid and soda is called sulphat of 
soda. 1 riple salts are distinguished by sub- 
joining the names ot both the bases connect- 
ed by hyphens. 'I Inis the compound of tar- 
taric acid, potass, and soda, is called tartrat of 
potass-and-soda. 
The salts then naturally divide themselves 
intu two grand classes ; The first of which 
comprehends the alkaline and earthy salts, 
which derive their most important characters 
trom their acids; the second comprehends 
the metailme salts, whose bases on the con- 
trary stamp their most important properties. 
Salts, or the combinations of alkalies with 
acids which exist in the mineral kingdom, 
constitute the following genera and species: 
Genus I. Potass. 
Sp. 1 . Nitrat of potass. 
