On the other hand, I there prove, that the acid in essential oils is super-abundant, and in some sort foreign to their nature, or that it is but slightly connected with them, and in part deserts them every time they are distilled; which renders them less soluble after every new rectification: whereas, on the contrary, the fat expressed oils in their natural state give not the least sign of acidity, but the action of fire upon them discovers an acid which was not perceivable before. Hence I conjecture, that these oils contain no more acid than is just necessary to constitute them oils; that this acid is intimately blended with their other component parts; that it is so sheathed and entangled by these parts as to be incapable of exerting any of its properties; and that on this account these oils in their natural state are not soluble in spirit of wine: but that the disposition of their parts being gradually changed by the fire, and their acid, being by that means set more and more at liberty, at length recovers its properties, and particularly that of rendering the oily parts soluble in an aqueous menstruum: and hence it follows, that the fat oils become so much the more soluble in spirit of wine the oftener they are exposed to the action of fire. Spirit of wine doth not dissolve fixed alkalis; or at least it takes up but a very small quantity thereof; and hence ardent spirits may be freed from much of their phlegm by means of these salts thoroughly dried: for as they strongly imbibe moisture, and have even a greater affinity than ardent spirits with water, if a fixed alkali, well exsiccated, be mixed with spirit of wine that is not perfectly dephlegmated, the alkali immediately attracts its superfluous moisture, and is thereby resolved into a liquor, which, on account of its gravity, descends to the bottom of the vessel. The spirit of wine, which swims at top, is by this means as much dephlegmated, and as dry, as if it had been rectified by several distillations. As it takes up some alkaline particles in this operation, it is thereby qualified to dissolve oily matters with the greater facility. When rectified in this manner, it is called _Alcoholized Spirit of Wine_. Yet spirit of wine, even when rectified to an alcohol, is not capable of dissolving all oily matters. Those named Gums will by no means enter into any sort of union therewith; but it readily dissolves most of those which are known by the appellation of Resins. When it has dissolved a certain proportion of resinous particles it acquires a greater consistence, and forms what is called a _Spirit Varnish_, or a _Drying Varnish_, because it soon dries. This Varnish is subject to be damaged by water. Many sorts thereof are prepared, differing from each other according to the different resins employed, or the proportions in which they are used. Most of these Varnishes are transparent and colourless.