Yes. Dissolved either in oil, or in alcohol, resins form varnishes. From these solutions they may be precipitated by water, in which they are insoluble. This I can easily show you.—If you will pour some water into this glass of mastic varnish, it will combine with the alcohol in which the resin is dissolved, and the latter will be precipitated in the form of a white cloud—
EMILY.
It is so. And yet how is it that pictures or drawings, varnished with this solution, may safely be washed with water?
MRS. B.
As the varnish dries, the alcohol evaporates, and the dry varnish or resin which remains, not being soluble in water, will not be acted on by it.
There is a class of compound resins called gum-resins, which are precisely what their name denotes, that is to say, resins combined with mucilage. Myrrh and assafœtida are of this description.
CAROLINE.
Is it possible that a substance of so disagreeable a smell as assafœtida can be formed from a volatile oil?
MRS. B.
The odour of volatile oils is by no means always grateful. Onions and garlic derive their smell from volatile oils, as well as roses and lavender.