1000000030

largcs in proportioo to the

d~grec

of hcat applied to it ;

thc confequence wherrof is, that Ihe (JI,le fpace nolV

cOfl[dins fewer partides of ai r than it did

b~fore.

Cold

again produces jun Ihe contrary efTdL

On Ihis property which oir has of beiog condenfed ond

dilmd by he.u, its elatlicily chidly dcpcnds. For i( air

~rere

forccd by coudcnfalloll ioto a Iris compa(s Ihan it

took up be(ore, ond Ihen rxpofeJ

a I'er)' coulidt14Dle

4egr<e o( colJ, it IVouhl rcmaio quite inaail c, wllhoUI

exertiu~

(uch

011

c[,'n as it ufually IIl.Ikes againn Ihede.

prenillR boJy. On the other haod, the d.lnicily of

heateJ air

~lifl'S

only (rom hcnee, tha¡ being r",fiL<1 by

tllc aaion of ore, ir Icquires much \llore ruom than i¡

ow 'pied

~e!'cre.

Air enters ioto the compoGtion of many (ubaonces,

c(l'eci,lIy

l'egc('I~le

ond anlmJI bodies: For by anal )'lillg

moa o( thtm

fu~h

o conodcrable quantil)' Ihereof is ex–

tricateJ, thal (ome natufdl itls hare

(u(pel~l'J

il lO be al

10-

gelher ddlitute of cl,nieity when thus combined with Ihe

o¡h", principies in Ihe compolidon o( bodll's. Accoroing

them,

tl.le

ellicacy o( Ihe eI.,nie pOll'er of the oir is ro

prodigious, and ils force when comprell'eJ lo excdlil'e,

that il is nOI polJible the other co:l;i,oneot pa:!; of bo·

dies Ihould be able

con~nc

fo much of it in Ihat (bte

of comprelJion which it mun nm ls undergo, if retaining

iú

c1anicily \Vhen penl ul' alllong them.

Howel'er thal be, Ihis d an,c propllty of Ihe air pro·

duces ¡he motl ling"br and impOl lant

pheuom~o.

obfer–

vable in Ihe rtfolu tion aod compofilion o( bodies.

A TER.

TER

is a thing (o wdl known, Ihat it is almofl

needlefs to m empl givirg a general idea of il hcre. E–

very one kno\Vs

th~1

it is a tranfparent, inopid fubnance,

and ufu.lly fluid. Wc f.1y il is ufually (o; for belOg expo–

fed tOacenain degree of cold, it becomcs folid: Solidily

Iherefore (eems to be ils mol! natural aate.

'Valer expofed

rhe ore grows hor ; but only to •

limilcd degree, beyond which iu heat never rifes, be

thc force of lire applied tOit ever (o violent: [t is known

to hal'e acquiren Ihis degree of heat by its boiling up

with gre.t tumult. W'aler eaonot be made bOlter, be–

c.u(e it is volatile, and incap.ble of cnduring lhe he.t

wilhout bei ng evoporated and entirely diffipated.

fu cha violent ar.d fudden heat be applied lO water

as . 'ill nor allow it time tO

e~hale

gently in vapou'rs, as

",hen, for inflance; a fmall quantilY thereof is Ihrown

u'p0n a metal in fufion, it is diffipa¡ed

:11

once wilh vafl

impetuofit y, prodllcing a

moa

lerrible and dangerous ex–

pIoo"n.. This fllrprifing

d!':t\

may be

dedur.cd

fro01 Ihe

inlhntaneous d,Jamion of Ihe pans

01'

Ihe water itfelf,

01'

r.,·her

01'

the ai r contained in il.

Moreover, water

eOlm ioto the texture of many bodies, both compound

and (tcondar)' principies ; but, like "ir, ir (eems to be

e~c1uded

flom Ihe compofition of all metals, and O1ofl

minerals.

ahhoug!' an immenfe qllantity of wmr

exias in Ihe bowels of Ihc earlh, moifleniog all its con–

tenIS, il does not Ihercfore follolV, ¡har It is One of Ihe

principies of minerals

is only interpofed bttween

tbeir pans

(01'

they may be entirely robbcd of it, \Virb-

out any fort of decompofition: [nnl!ed it is not capable

01'

ao intimale cOlloe/uoo with them.

E •

R T H.

\VE obfervcd, Ihat lhe two principles'abol'e tremn nf

are volalile ; Ihat is, the aaion o( ore feparate! Ihem

[rom Ihe bodi,·s lhey htlp

compole. Hm e",lh is fix–

ed, and, whell abfolutell' purt, Icfias the olmoa fOlce

of lire. So Ihat, whateler remains

( 1'

a bodl', after it

halb been eXI'0:ed

the power of the fiercefl fire,

mu~

be conodereJ as conlaining nearl)' all i¡s w lhy princi–

pie, and confiaillg chiefly Ihertof.

Earth there(ore is a fixed principie whieh is per01anent

in Iht ri re. T11ere is re.filO lO Ihink il very dlilicull, if

not impolTible, tO oblain Ihe terrene principie IVholly

free fromcvery olher (ubflance : 1'or , /ter our IlImnn

endeavours tO pUlify thrlll, Ihe earlhs we oblain from

di!ferenl compouods are found to have di[el'tnl proper–

ties, according (() the di!fcrenr bodies fl'OO1 which Ihe)' are

p(ocored

or dfe, if rhofe eanhs be pure, IVe mufl al–

low Ihem lO be eilentially differenl, fee:ng they have dif–

ferent propenies.

Eanh, in general, wilh regard lOjls propenies, may

be diaributed into

l uJihl-

ano

u"¡l/jiUe;

Ihdl is, inlO

e.nh

Iha¡ is capable

01'

melting

01'

becoming fluid in the

Gre, and earth Ihal coon, ndy rtm, ios in a (olid form,

never melting in ¡he IIrongdl Jegree of heat to which \Ve

can expofe il.

The former is alfo calleJ

virlif. bl_,

and the Iat–

ter

ullujtriji..

b/<

eanh; beedufe, when e.rth is mell–

ed by the force of fire, it b<comes what \Ve call

g/uf,

\Vhich is nOl hing bUl Ihe pm! of c:Inh brought into

nearer COnlaa, and more c10fdy uniled by thc means of

fufion. Pedraps ¡he eanh. wbich IVe look upon as unca–

pable of vil riocalion, might be (ufed if IVe could

ar~ly

to ir a rullicient

d~gree

of heat.

is al lea(l cennin,

that fome tarths, 01' flones, which fepal m il' rclifl the

force

01'

ore, (o Ihat Ihey cannol be mtlled, become lu–

oble when mixed togelher. Experience con, inced Mr

du Hamel, that lime-none and lIale are o( this kinJ .

is however undoubledly true, thal one earlh di fFers

from anolher in ils degree of fuGbil ilY: And Ihis givcS

ground

be!.eve, Ih.u Ihere may be a fpecies of eanh

abfolutely unvitriliable in in nalllrt, which, being mixcd

in different proportion! with fufible eanhs, rendars thcOl'

dillicult to melt.

Whatever may be in this, as Ihere are eanhs which

we are ab(olutely unable to vitrify, Ihat is o fullicient

rea(on of our divifion of lhem. Unvitrifiable earths feem'

to be porous. for Ihey imbibe waler; whence they have

al(() got the oame

01'

avforbMI ( ..

,lnJ.

°IFIl!.

TH Emaller of the fun , or of lighl, Ihe phlogiaon,.

ore; (he rulphureous principie, rhe inflammoble maller,

ale all o( Ihtm oames by which rhe e1ement of Ore is u–

fually dcnoled. But il Ibould feem, Ihal an accurale

dlibnaioo halh no! yet been made between Ihe d,ff, rent

aate, io which it eJcias

!hat is,

betweeD!h~

phenomena