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m th in thcir comporttion; or, laaly, they difrer on ac·

count of fome adtlitional principies, which not being como

bined

~ith

thcm in fll/licient

9u~ntity

lOhinder their Ca·

linc properties from appca ri"g, permit them to rClain the

name of (,t1ts, though

lh~y rtno~r

lhem I'ery different

fromthe Gmpldl C,line fubflances.

is eafy to infer from whal has becn faiJ nf f.!t s in

general, that Comeof them mun be more, rome

IcCs.

lixed

or I'olatile than others, and fome more, fOll1e IcCs, dif·

poCed

unite with water, with eanh, or with particular

rons of eml,. aecordillg 10 lhe nalure or the proporti6h

of their principlcs.

Refore

\Ve

praceed further, it is proper jun 10 mention

lhe principal reaCons which induce us to think lhal every

Caline fublbnce is aauallya combination of earthand wa·

ler, as \Ve Cupporeo at our entering 00 this rubjea. The

r,rn is, the conformilYf.!ts havewith earth and waler, or

rhe properties lhey polfcfs in common with both. Of

thefe properties \Ve OJaIl treat fllll y, as occaGon offers 10

conGder lhem, in examining lhe feveral rons of Calrs

T ho fecond is, lbal all f,lts may be aaually refolved in·

earth anO water by fundry proceO'cs; particularly by

repe,lled difiolution in waler, eupor:uion, deGccation,

and calcinalion Indeed lhe chemills have nOl yet been

able 10 produce a faline Cubllance by combining earth and

water togclher. T his favours a fufpicion, lhat befides

theCe 1100 lhere is fomeolher principie in the compofition

of f.,lts which eCcapes oor refearehes, becaufe \Ve cannat

preren'e il when we decampare lhem: bUl it is fufficient

ta our purroCe, that water and eanh are demaollrably a·

manglllhe real principies af falinc Cubllances, and that

no experiment hath ever fhewn

liS

any alher,

o¡

T H! Gmplell faline fubllance is that cal,led an

ocid,

accauOl af ilS lane, which is like that af verjuice,

Corre!,

,'ineg.r, and ather Cour things. whieh far the fame rea·

fon >re alCa called acids. By lhis peculiar talle >re acids

chieOy knawn, They have mOreaver the praperty of

lurning . lIlhe blue and violel colaurs of

veger~bles

red,

which dillinguifhes them fram all ather fa!ts.

The form under whieh acids moll commonlyappear,

js lhal of a tranfparent liquor; lhough Calidily is rather

lhei r nalural lIate. This is awing la lheir aflinilYwith

waler ; which is fa greal, lhal, when they cantain but

jull a, much of il as is nmfrary ta conllitule them Calrs,

aod c1nCc9uently have a Colid form, lhey rapidly llOite

lherewith lhe momenl lhey come iota canlaa Wilh it:

andas the air js always loaded \Vith maillure and aqueaus

'apollrs, its cantatl alane is Cufficienl ta liquify them ;

bmufe they uuite with its humidity, imbibe il greedily,

and by thal means becomefluid.

thmfare fay, lhey

attraa the maillureaf lheair. This change af a Calt

frama Colid ta

fluid lIalc, by the fole contaa af Ihe

air, is alfo eallet!

drli7l1illlll:

lhat when a fall changes

in this manner frama folid inla

Ruid farm, il is faid la

run

pu "-liqlli,,",.

Acids being the fimplell fpecil! af

f.line bodies,

th.ir

aflinities \Vith d,frerenl fubfiances are

IIronger than thaCe of any ather fon of falt with rhe (Jme

{ubfianecs; \Vhieh is agreeable

OUt

faunh prapafitian

taoceroing

aJliruties.

Il.

Aeids in general have a grcal affinity with Farths:

thal with which they moll readily unitc is th. unvitrifi·

able eanh ta whieh lOe gave the nameof ablorbent carth.

They feemnal

aa at allupan "i"ifiable carrlts, fucl.

as fand; nor yet upan Come alher kinds of calths, at

leallwhile theyare in their natural lIate.

ye¡

th~

na·

ture of th& earths may be in Come medlure changcd, by

making them red hm in lhe fire, aO(I thell qllenching

themCutldellly in caId water: for by repeating this oltcu

theyare brallr,ht nearer 10 the n:lture

abCarbenr earrhs,

and rendmo carable of uniting with :Lcicls.

Whenan aeid liquor is mixetl \Vith an abCal'bent eanh,

for inllance with chalk, thefe

t \Va

lubllances inll"ntly

rUnl inlo union \Vith fa much impetuoGty, that a great e·

bullitian is immediatcly praJue-J, 3tt<r.d¡·cl wirh conGo

der, ble hifiing, he,lt , and vapours, which rife the very

inflant af their canjunaian.

From the cambinatian of an acid \Vith an ahCarbent

emh rhere ariCes a new compound, which Come

chemil\~

have called

.fal

f"!f"lll;

becauCe the acid by unlting with

the earrh lafes its faur tafle, antl acquires anolher not

unlike that of the cammon Cea·Iall ured in aur

kltch~ns

;

yet varying aecarding ta the difrcrcnt forrs af aeiJs and

earths eambined tagcther. The ami al the fame lime

10Ces ltl praperty al' turning blueor vi"lel regel.bles red.

If we inquire \Vhat is·beeome af its prapenGly ta unite

\Vith water, we fhall find thal the eanh, which of itfelf

is nOl faluble in water, halh by its union \Vith the acid

acquired a facility af dirTalving therein;

that oor

fal

fa!f1l1ll

is Caluble in water. !lul, on theather hand, the

acid hath. by its unian \Vith the earth, Ion part

the

aflinily it had Wilh water;

thal if a

jol

faiju/II

dried, and freed af all fuperfluaus hemidity, il will re·

main in thal dry folid form, inllead af amaéling the

maillure of the air and running

ptr

drliqtdum,

as the acid

would do if it were pure and unmixed with eanh

A(id,

have

likewif~

a great affinÍty w¡th the phlogillan.

When we eOOle ta treal of each acid in particular, we

fhall examine the combinatians of each with the pllla–

gillon: they dilTer fa widdy fram one

anot~cr,

and Old'

ny af

lh~m

are fa little knawn, lhal we cannal at preCeol

any general idea of them.

L K A L

r s.

ALK.lLtS are faline cambinarions in which there is

greater prupartian of mth than in acids. The princi.

pal arguments that Olay be adduced to prove lhis faa

ar~

theCe: Firll, if they be trw cd in the manner propafed

above for analyfiog (,.Iine fubnanm, lOe abtain framlhem

a much greater quantity af carth than we do fram acid••

Secandly ; bycambioing

cen.in

aéids \Vith certain eanhl

lOe ean produce alkalis; or at lean fuch falinc compaunJs

as grcatly rcfemble ahem. Our lhtrd and

1.11

argument

is dl'1l\Vn fram the properties af thafe alkalis whieh,

wl,e~

pUfe and unadulter3ICd wirh ny atiJer prinCipie, have

lefs aflinity with water than uids have, and are alfo

more Gxed, refilling the.utmall force of fire. On Ihil

accouol il is thal they hal'e obtained Ihe litle of

fixtd,

as \vell as ta difiingUlfh tl¡em (rom anather Cpecics af

.Ikali, la be cOIIGdercd hcreafu:r, which is impure and

valatile.

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