1000000030

61e by d<:grm as you find it necdfary fOI the e1evation of

the thick oil. This oil, Or rather this kind of bumr,

\ViII be at MI of a ru(fet colour. There will rife

~Iong

'vith it fome \Vhile vapours exeeeding Omp and pungent.

When yóu obferve that nothiog more comes

over,

though the reton be quite red·hot, let the velrc¡' cool,

~Dd

uolute them. You will fiod io the rceeiver an aqueo

ous acid liquor, a fluid oil, and

kiod of 6xed brolVn

burter. I:lreak the reton, and you ",ill find Ihertin a

kiod of charred mmer; the furface of \Vhich, where it

louched Ihe gla[s, will be of a fhiniog block, and have a

boe polifh.

The analyfis of butler proves, that Ihis fubllance,

'vhich is ao oily matter in aconerele form, owes its con.

lineoce tO Ihe acid ooly, IVilh IVhich 'the oily pan is

eombined: that is, it follows Ihe general rule freqqently

mentioned above in treating of other oily compounds ;

Ihe confinence whereof we fhewed to be fo much the

!irmer, Ihe more acid they contaio. TIte fitn portions

of oil thal COrne om iDthe dillillatioo of buttu are

fiui<!, becaufe a prwy confiderable qu.ntity of acid rofe

before them, which, beiog mixed with the phlegm, ¡;ives

the acidity we took ootice of.

Thjs oil, being f.e:d from ils acid, and by tha! means

rendered Ruid, rifes firn ; becaufe it is by lhe fame means

rendered lightet. The kind of bUller thOl comes

over

aflerwards, though it be fixed, is oeve<lhe/efs

fir

from

having the fame confinence as it had before

din;lI~tioo

;

Decaufe it lofel much of its acid in lbe operalion. This

acid is whu rifes in the form of white vapoun. Tbefe

vapoul! are at lean as puogen! aod irritating as the fuI·

phureous acid or volatile alkalis : but lheir froell is dif·

ferent : i! hath a refernblance, or rather is the fame,

with thal which rifes from burter wheo il is burot and

browned in ao open

~(fel.

Bu!, wheo concentraled

and collc{\ed in clofe ve(fe/s, as in lhe dinillation of

hurter, they are vanly nronger: !hey irritate lhe lhroal

fo as lO inRame il; they are exceeding Omp and puno

gem 10 the fmell. and are fo hurtful to the eyes Ihat

lhey quickly ioflame them, as in ao ophthalmy, and

and make Ihem fhed abundance of lears. The great vo·

btility of Ibis acid is eOlirely owing to a portion of the

phloginoo of the bUller witb lIIhich it is Hill combined.

We took notice in the proeefs, that burter feems to

boil wilh a very moderate heat at Ihe beginning of Ihe

dinillation, and that ·io tbe courfe of the operatioo the

ebullitioo ceafes enlirely, though the heat be then great·

Iy inereafed

whieh is eontrary tO the general rule.

TIte reafoo is, that burter, though a f.etllingly homoge·

neous mafs, cootains nevenhelefs fome partides of chcefe

aod whey. The partides of IVhey, being mueb lhe

lighteO, endeavour, on the firn application of heat, to

extricate .hemfelves from amongn lhe particles of bUller,

aAd tO rife in diOillation. Thus they form Ihe drops

acidulmd phlegm ",hieh come over at firn, aod, in nrug.

gling

g,·t free, lift up the bumry pam, or aélually

bClil, IVhi,:h occafions the ehullition obfervable at the be·

tillmng of the proeefs. When they are once feparmd,

Iltl mtll" d bumr remains ,,1m and fmooth . without boil·

ing.

you want to make it boil, you mun apply a mueh

~rrmr

dtgree of heat; which you canoo! do in clofe

VOL.

11. No.

173

.,(fd!, withont fpoiling the \\Ohole operation: bmufe

the degrce of heal n-cc(fdty for th' l purpufe woulJ force

IIp the bumr in fubn.nce, \Vhieh Vlould rufh

ovtr

into

the reeeiver, without any decompofitioll. Indeed if th.

vclrds were IUled, they woultl be in d"nr,er of burOing.

As 10 the cafeous pans, \Vhich are mixed ",ilh f"fh

humr, they airo feparate at Ihe begioning of the dinil.

hlion \Vhen the buuer is mehed, and garher on in (ur.

face in a feum. Thefe partides of eheefe and whey,

\Vhich are heterogeneous tO buuer, help tO make it fpoil

the fooner. And for this reafon, thofe who want tO'

keep bulter a long time, without Ihe ufe of falt, meh ir,

and thereby evaporale the aqueous pam. The lighten

portion of Ihe partides of cheefe rifes 10 the furface, and

is n,immed off; the rel! remaios at the boltom of the

ve(fcl, from whieh the bumr is eafdy feparared, by de.

eanting it while il is

yct

Ruid.

BUller may alfo

dillilled, by incorporaling it with

fome additament which will yield no principie itfelf, nor

retain any of thofe of the bUlter.

-Ir

may be dinilled ia

this manner with the additanoent of fine fand: the ope–

ration fucceeds very welJ, is fooner boifhed, and more

eafily eonduéled.

If you defire to conve't the bulter wholly into oil,

you mun taJee the fixed maller you find in the receiver,

and Mlil it ooce more, o, oftener, according to the de·

gree of fluidity you want to give it. The cafe is the

fame with this matter as with all other thick oils, whieh,

the ofteoer they are dinilled, grow always Ihe more

Buid, becaufe in evuy dillillatioo they are feparated from

pan of the acid, to \Vhieh alone they owe their eoofill·

eoce.

'rheCurtl

MitA analy/ttl b, DiJlillalion.

INTo a glafs retort put fome oew curd having (¡r/l

draioed it thoroughly of all ils whey, and even fqueezed

it iD a linen cloth to exprefs all its moillure. Dillil it as

you did bumr. There will come over at 6rn ao acido·

lated phlegm, fmelliog like cheere or \Vhey. As the

dillillatioD advances, the acidity of this phlegm will iD–

ereafe.

When it b.gins to ruo but very Oowly, raife yoor

~re.

There will come over a yellow oil, fomewh.t em·

pyreumatie. Cootinue the diHillation, nill increafing

the (¡re by degrees as oec.fion requires. The oil and

cid phlegm will continue tO rife; the phlegm growiog

gradually more acid, aod the oiJ deeper

.~oloured

and

more empyreumalie. At lall, \Vhen the retort is almo/l

red.hot, there comes off a fecond black oil, of !he con·

finene. of lurpentine, vdy empyreumatic, and fo heavy

as to fink in waler. lo the reton will be left a coofi·

-der.ble quanlity of eharred matter.

Cheefe·cu,d barely drained, till no more whey will

drip from it, is not entirely freed thereof; and for

this reafon we direéled it tO be prc(f.d in a I,nen doth,

before it be put ioto the retoll to be diniflcd. Without

this precamioo, the rem.ining whey would rife in a con·

fidmble quantity on thefirll applicarion of heal; Md, in–

lIead of analyfing thecurd only, IVe fhould at the fame time

aoalyfe the whey alfo. This is to be

und.rf!

od of green

eurd aod oelV·made cheefe; for,

luffe'ed to gro",

. t

oId,