CHEMISTRY. 
5s a bad preparation, as the combination is not com¬ 
plete. All the dulcified acids are decompofed by alka¬ 
lis. It feems that, in the preparation of dulcified acids, 
>a little ether it formed; but the quantity of water and 
acid, hinder this from being exactly known. 
Alcohol readily unites with the boracic acid; this li¬ 
quor flames, and burns with a red colour. Its adtion 
with the other acids has been little examined. It readily 
difiolves potafli; this is the method ufed for purifying 
potafh, and procuring it in cryftals, as detailed in p. 2.2.4. 
By the digeftion of the alkali obtained from tartar in 
alcohol, two remedies are compounded, called acrid tinc¬ 
ture of tartar, and jnetallic tinfture, or lilium of Paracelfus, 
which laft only differs from the firft in that the alkali 
ufed in preparing it has been rendered cauflic by heat. 
Alcohol unites with all the deliquefcent falts, and 
keeps them from being precipitated by water. If, for 
inftance, a folution of muriat of lime be taken with al¬ 
cohol, and let on fire, it will give a red colour; with 
muriat of ftrontian and alcohol, a purple red. Some of 
the metallic falts are alfo foluble in alcohol; as, the fu- 
per-oxygenated fulphat of iron, the nitrat of copper, the 
muriats of iron and copper, and the oxygenated muriat 
of mercuiy : all the falts of copper burn with a beautiful 
green flame. Guyton has given a table, in the Jour¬ 
nal de Phyfique, of the degrees of folubility of falts in 
alcohol. 
Soap is very foluble in alcohol, efpecially if a little 
potafh be added: this folution, when perfumed, is called 
ejjbice of foap. Some of the immediate produfts of plants 
are foluble in alcohol, others are not; fome are foluble 
in alcohol and in water, others only in one of the two, 
others again in neither, as the ligneous fubftance. 
Among the fubftarices foluble by alcohol, are extra&s, 
fugar, and fome vegetable acids, as tartareous acidule, 
oxalic, camphoric, and benzoic, acids. If diftilled water 
be added to a folution of camphoric acid, there is no 
precipitation; but a precipitate is obtained by pouring 
water into an alcoholic folution of benkoic acid ; which 
exhibits a marked difference between thefe acids. If al¬ 
cohol be diftilled in a water-bath with odoriferous plants, 
the fpirit feizes the principle of fmell, and rifes with it, 
carrying up at the fame time a certain quantity of vola¬ 
tile oil, which caufes it to become white by the addition 
of water: in pharmacy thefe are called fpirituous dif tiled 
c,waters . 
Volatile oils are entirely foluble in alcohol; if thick 
and much coloured, they become lefs fb. Camphor alfo 
is foluble in alcohol, but is precipitated by water : in this 
way is prepared camphorated alcohol. 
Alcohol difTolves refins and gums alfo : thefe folutions 
are called tinSlures , elixirs, ^uinteffences, See. The refins 
may be feparated from the alcohol again, by pouring- 
water over the tindtures. The folution of a gum 'refin 
in weakened alcohol, gives a refinous precipitate; but 
the water continues coloured, and holds a part of the 
gum in folution. This proves that the alcohol difiolves, 
by help of the refin, a fmall portion of the gum; and, 
reciprocally, that the water difiolves a fmall part of the 
refin by the help of the gum ; fo that the analyfis of a 
gum-refin by water and alcohol cannot be very exaft. 
Ballams difl’olve in alcohol. Benzoin, for inftance, in 
alcohol, gives a tindlhre, called virgin water. A few 
drops of this in water turn it white, which has gained it 
the name of virgin milk. Water does not decompofe tlie 
tindlures formed with extradto-refinous fubftances ; as, 
rhubarb) faffron, opium, See. becaufe they are equally fo¬ 
luble in either liquid. 
The property of alcohol to diflolve refins, has given 
rife to a mode of fpreading them on the furfaces of bo¬ 
dies for ornament or prefervation, under the name of 
varnifses. For the moft beautiful varnifhes, the moft 
tranlparent refins fhould be ufed. To thefe tindtures are 
occafionally added a certain quantity of volatile oil ; as, 
oil of turpentine, oil of afpic, or the greater lavender; 
Vol. IV. No. 202. 
349 
thefe give confiftence to the varnifli, hinder rt from dry¬ 
ing too faft, and ferve to unite the refinous parts when 
the alcohol has evaporated. In this manner, fandarac, 
maftic, copal refin, lac, and colophony, make very good 
varnifh. 
Of ETHERS. 
The oldeft of all is the fulphuric ether. Put a certain 
quantity of alcohol into a retort, and pour over it by 
degrees an equal weight of concentrated fulphuric acid; 
agitate and ftir the mixture, that the retort may not 
break by the heat. Place the retort on a warm fand- 
bath ; adapt two large balloons, of receivers, plunged 
into veffels of cold water; and care muft be taken to 
keep the firft receiver cool with wet cloths. When the 
apparatus is mounted and luted, urge the mixture to 
ebullition, which will take place at 78° of heat; then a 
fluid will be produced, which, by cooling, condenfes 
into a white liquor, light, of an agreeable fmell, which, 
from it properties, has received the name of ether. If 
the operation be lkilfully conduced, no permanent gas 
will be difengaged till about one half of the alcohol is 
converted into, ether. As foon as the fulphureous 
acid appears, the receiver (hould be changed; then no 
more ether will be produced, but a little yellowifh oil is 
volatilized, called fweet oil of wine ; there is water alfo„ 
and acetous acid, but not an atom of carbonic acid. 
When fulphuric acid makes about four-fifths of the mals 
remaining in the retort, an inflammable gas is difen¬ 
gaged, having the fmell of ether, and burning with, a 
white oily flame: to this gas the Dutch chemifts have 
given the name of carbonated hydrogen gas, or olifiant gas, 
becaufe, mixed with oxygenated muriatic acid, it forms 
oil. At this time the temperature in the retort is raifed 
to 88 or 90 0 . When the fweet oil of wine no longer 
flows, change the receiver again; nothing is now pro¬ 
duced but tulphureous acid, and the water formed be¬ 
fore by the carbonic acid gas; and in the retort there 
remains a mafs, the greateft part of which is fulphuric 
acid blackened by carbon. 
Fourcroy and Vauquelin affert, that a mixture of equal 
parts of fulphuric acid and alcohol, will not boil till there 
are 78° of heat, but alcohol alone boils at 64°, whence 
they conclude, that alcohol is reftridted by the affinity 
of fulphuric acid, which fixes it. They compare this ef- 
fedl with what takes place in every other vegetable fub¬ 
ftance expofed to heat, whofe principles fly off according 
to the order of their affinity for caloric, carrying with 
them a fmall quantity of the more fixed elements. Thus, 
in proportion as the fulphuric acid attracts alcohol and 
water, of which it promotes the formation, the ether 
which is produced attracts caloric, and becomes volati¬ 
lized ; and-, when the greater part of the alcohol has been 
converted into ether, the mixture becomes more denfe ; it 
requires a more confiderable heat; and, the affinity of 
the fulphuric acid for the undecompofed alcohol being 
increafed, the principles of that acid are disjoined; io 
that, on the one hand, its oxygen is driven upon the hy¬ 
drogen of the alcohol, and forms water, which volati¬ 
lizes by degrees ; while, on the other hand, the ether, re¬ 
taining a greater quantity of carbon with which it can 
volatilize at that temperature, gives rife to the fweet oil 
of wine, which ought to be confidered as ether more 
loaded with carbon ; as is proved by its increafed weight, 
lefs volatility, and its lemon colour. 
From this Ample theory, which is drawn from the fadls 
and obfervations contained in their writings, we are led 
to the following ufeful conclufions : 1. That the forma¬ 
tion of ether does not arife, as was fuppofed, from the 
immediate adlion of the principles of the fulphuric acid 
upon thofe of the aldohol, but upon the re-adtion of the 
elements of ttye alcohol upon each other, particularly of 
the oxygen and hydrogen, occafioned only by the ful¬ 
phuric acid. 2. That alcohol may be converted into ether 
withou the affiltance of heat, by increafing fufliciently 
4 U the. 
