3S a C H E M I 
in ; fo that one of the veffels is filled, and the other only- 
half full. The fermentation commences in the latter : 
when it is well eftablifhed, it is filled up with wine added 
from the other tun. By this means, the fermentation is 
retarded in the full veffel, and accelerated in the other. 
When it has arrived at a confiderable degree in this laft, 
it is again filled up, by transferring part of the fluid from 
the other; the fermentation confequently recommences 
in the firlt veffel from which the liquor was laft taken, 
and becomes flower in that which is filled up. The al¬ 
ternate filling and emptying of the veffels is continued 
till the vinegar is perfectly formed, which ufually happens 
in twelve or fifteen days. When the effects of this fer¬ 
mentation are attended to, much ebullition and biffing 
is perceived; the liquor becomes hot and turbid, exhibits 
a great quantity of filaments and bubbles, agitated in 
every direction; a ftrong acid firnell, not. at all dangerous, 
is emitted, and a large quantity of air is abforbed. It 
is neceflary to impede the fermentation every twelve 
hours. Thefe. phenomena gradually become lefs, the 
heat decreafes, the motion decays, and the fluid recovers 
its tranfparency: a fediment is depofited, in reddifh 
flocks,which adhere to the fidesof the veffels. Numerous 
experiments havefhown, that the fmaller the quantity of 
wine, and the more perfeft the accefs of air, fo much the 
more readily does it pals to the Hate of vinegar. The 
vinegar muft be carefully drawn off, in order to feparate 
it from its lees, which, without this precaution, would 
quickly caufe it to undergo the putrid fermentation. 
Vinegar does not depofit tartar by Handing, like wine; 
this fait is diffolved, and combined with the alcohol and 
water during the fermentation. It is even probable, that 
the prefence of this fait influences the developement of 
the properties of vinegar- This fluid has more or lefs co¬ 
lour, according to that of the wine ufed in its prepara¬ 
tion ; but in general, vinegars, which have the leaf!: co¬ 
lour, are far from being of as light a colour as the white 
wines, becaufe they hold in folution the colouring matter 
of the tartar, which has likewife been developed by the 
production- of the acid. 
Vinegar, prepared in the method here defcribed, is 
very fluid; of an acid and fpirituous fmell, and of a 
four tafte, of different degrees of ftrength : it reddens 
blue vegetable colours. When expofed to a warm tem¬ 
perature, in imperfectly clofed veffels, it becomes changed, 
lofmg its fpirituous part, and depofiting a great quantity 
of mucilaginous flocks and filaments, at the fame time 
that it affumes a putrid fmell and tafte. In order to pre- 
ierve it, it is neceflary to boil k for a (hort time, as Scheele 
has oblerved ; but this did not fucceed with Nicholfon. 
When vinegar is diltilled by a naked fire, in an earthen 
alembic, or in a glafs retort, on a fand-bath, a phlegm 
of a lively and agreeable fmell, but fcarcely acid, firft 
pafles over; this is fucceeded by a very white acid liquor, 
called difilled vinegar., or acetous acid. The following 
produfts have lefs Imell, and more acidity, as the diftilla- 
tion advances. If thefe products be taken feparately, 
diltilled vinegars, differing from each other in acidity 
and fmell, m ty be obtained ; but it is ufual, in this procefs, 
to draw on about two-thirds of the liquor, which confti- 
tutes the pureft vinegar. The portion which comes over 
afterwards is more acid, but it has an empyreumatic 
fmell, which may be dililpated by expolure to air; it is 
likewife flightly coloured. This operation Ihews, that 
the acetous acid is lefs volatile than water. The remain¬ 
ing vinegar is thick, of a deep and dirty colour, depofits 
a certain quantity of tartar, and is conliderably acid. If 
it be evaporated in open veflels, it takes the form of an 
extraft; and If, when dried, it be diltilled in a retort, it 
affords a reddifh acid phlegm, an oil at'firff light co¬ 
loured and afterwards heavy, with a fmall quantity of 
ammoniac. The remaining coal contains much fixed 
alkali. ' Vinegar may be concentrated by expofing it to 
froff. The frozen part c nfifts almoit entirely of water; 
the part which remains fluid, being decanted off, is found 
i 
S T R Y. 
to be much more acid: the quantity of vinegar thus ob¬ 
tained is fmall. 
The acid of vinegar, feparated from tartar and the co¬ 
louring matter, by diftillation, is capable of uniting with 
a great number of bodies. It does not readily combine 
with alumine, with which it forms cryftals, in fmall 
needles, whole properties are little known. It is the ace- 
tit of alumine. This acid unites readily with magnefia, 
and affords a fait, which is very foluble in water, and 
does not afford cryftals, but is converted into a vifcous 
deliquefcent mafs, by evaporation. The acetit of mag- 
nefia is decomposed by fire, by the mineral acids, by ba¬ 
rytes, by lime, and by the alkalis. It is very foluble in 
alcohol. 
The acetous acid combines with lime, and decompofes 
chalk, whole acid it difengages, in the form of an elaftic 
fluid. The fait it forms with lime, cryftallizes in very 
fmall needle-fhaped priffms, of a fatin appearance. The 
calcareous acetit is hitter and four, and efflorelces in the 
air. It much refembles the acetit of magnefia, differing 
principally in not being near fo deliquefcent as that. 
To form thefe falts, the earths fhould be taken in the 
carbonat ftate ; the acetous acid, being poured over them, 
diffolves them, by difengaging the carbonic acid. They 
are all deliquefcent, more or lefs, and may be cryftallized 
by flow evaporation. But the combination of acetous 
acid with glucine will not cryftallize; it is reduced to a 
gummy appearance, preferving always a flight ductility ; 
it has fomething of a faccharine tafte, but more of the 
acid, and is very aftringent. The acetit of barytes is a 
very good re-agent to detect the prefence of fulphuric 
acid in vinegar; it has the greateft affinity for the ace¬ 
tous acid. All the earthy acetits are decompofed by 
fire : they afford a very fmall quantity of an acid oily li¬ 
quor; and the bafe, blackened by carbon, remains in 
the retort. Alkalis and mineral acids decompofe them 
alfo. Salts are formed, by the combination of acetous 
acid with alkalis, which were called terra foliata tartari, 
cryjlallized terra foliata , and fpirit of Mindererus . They 
are now called acetits. 
Vinegar ads on almoft all metallic fubftances, and its 
combinations are attended with a variety of important 
phenomena. The oxyds of gold and filver with acetous 
acids form acetits ; but thefe falts have not been yet ex¬ 
amined. It does not appear to difiblve the oxyd of arfe- 
nic; but this laft fubltance diltilled with an equal part 
of the acetit of potafh, afforded Cadet, and the chemifts 
of the Academy of Dijon, a red fuming liquor of a nau- 
feous fmell, very tenacious, and of a lingular nature. 
Cadet had before oblerved, that this liquor inflames fat 
lute. The academicians of Dijon, being defirous of ex- 
aming a yellowifh matter of an oily confidence, collected 
at the bottom of the veffel, which contained the arfenico- 
acetous fuming liquor, decanted a portion of this fuper- 
fluent liquor, and poured the reft on a filter of paper. A 
few drops had fcarcely palled, when immediately an of- 
fenfive and very thick fume arofe, which formed a co¬ 
lumn from the veflel to the deling; a kind of ebullition 
was excited on the borders of the matter, and a beautiful 
rofe-coloured flame iflued forth; all which lafted a few 
feconds. A full account of the experiments of thefe 
learned academicians, may be feen in the third volume 
of the Elements of Chemiltry of Dijon. They compared 
the liquor we have fpoken of to a liquid phoiphorus ; we 
think it is a pyrophorus of the fame kind as tliofe we 
fhall prefently mention. The refidue of the diftillation 
of the acetit of potalh with oxyd of arfenic, confifts, for 
the moft part, of potalh. 
Vinegar diffolves the oxyd of cobalt, and forms a fo¬ 
lution of a pale role colour. It has no adion on bifmuth, 
or its oxyd, but it diffoives that of manganefe. It dif¬ 
folves nickel diredly, according to Mr. Arvidfon; this 
folution affords green cryftals, of the form of a fpatula. 
The acetous acid does not appear to ad on antimony, 
but it appears to difl'olve the vitreous oxyd of this metal : 
iince 
