Part 7 (1/2)

LECTURE XVII

_Of Liquid Inflammable Substances_

Of liquid inflammable substances the principal is _spirit of wine_, sohly rectified, _alcohol_

It is obtained froh the vinous ferhter than water, colourless, and transparent, has a peculiar s

Ardent spirit seeiston and water; for when the vapour of it is h a red-hot earthen tube, it is resolved into water and inflahly infla any residuuiston so unites with dephlogisticated air as to make fixed air

Ardent spirit mixes readily ater in all proportions, and also with essential oils, and balsa inspissated

By its affinity with essential oils, ardent spirit extracts them froth aromatic plants; and these liquors have obtained the name of _tinctures_

When the tinctures are distilled, the more volatile parts of the essential oils, which come over in distillation, have acquired the name of _waters_; as _Lavender water_, _Rosemary water_, &c and what remains in the still is called the _extract_ of the plant If the tinctures be diluted with much water, the resinous part of the plant will be obtained pure, and separated from the extractive part, which will remain dissolved in the water, while the resin separates frouummy substances may be separated fro with the water only On the other hand, if resins be dissolved in spirit of wine, the affusion of water will separate them By means of the affinity of spirit of ater, it will seize upon the water in which several salts are dissolved, and thus produce an instant crystallization of thereater affinity to water than spirit of wine, and by extracting water fro it; but the bestspirit wine free fro before the water

Spirit of wine mixed with the vitriolic and other mineral acids, renders them milder, and thereby more proper for certain _ them

Spirit of wine is a powerful antiseptic, and is therefore of use to preserve vegetable and animal substances from putrefaction

_Of aether_

If spirit of wine be distilled with almost any of the acids, the produce is a liquor which has obtained the nahtness and volatility, being hter, and more volatile, than any other fluid that we are acquainted with It is highly infla of it is accompanied with smoke, and some soot; and on this account it is ataken from the spirit of wine part of the water that was essential to it, at the sa of its acid peculiarlyto the acids by which they are made; as the _vitriolic_, the _nitrous_, the _marine_, and the _acetous_ No aether, however, can be made froisticated; froisticated air is necessary to the composition of aether Vitriolic aether is the most co the easiest

aether does not mix ater in all proportions, like spirit of wine, but ten parts of water will take up one of aether It easilyreold, it will take froold that has been previously dissolved in it

By the quick evaporation of aether a considerable degree of cold may be procured; and on this principle it has sometimes been applied to relieve the head-ach and other pains

LECTURE XVIII

_Of Oil_

Oil is a liquid inflareat tenacity, disposed to pour in a stream rather than in drops It is little, if at all, soluble in water It burns with smoke and soot, and leaves a residuum of a coaly substance It consists of acid and water coiston

All oil is the produce of the vegetable or ani any of it

By distillation oil is in part decomposed, and by this means the thicker kinds of oil are rendered thinner and more volatile, the acid, to which their consistence is chiefly owing, being lost in the process By repeated distillation it is supposed that all oils ht almost to the state of aether, and even of ardent spirit

Acids act powerfully upon oils, but very differently, according to the nature of each Alkalies also combine with oils, and the less thin and volatile they are, the more easily are they soluble in alkalies The union of alkali and oil makes _soap_ All oil dissolves sulphur, and with it makes what is called a _balsam_ Oils also dissolve metallic substances, but most sensibly copper and lead United with the calx of lead, it is used in painting