Chap. XX.
Of Oily Preparatio?is.
495
Most of the volatile oils, indeed, are too hot and pungentto be tasted with safety : and the smell of the subject is somuch concentrated in them, that a small variation in this re-spect is not easily distinguished ; but we can readily dilute,them to any assignable degree. A drop of the oil may be dis-solved in spirit of wine, or received on a bit of sugar, and dis-solved by that intermedium in water. The quantity of liquorwhich it thus impregnates with its flavour, or the degree andquality of flavour which it communicates to a certain deter-minate quantity of liquor, will be the measure of the degreeof goodness of the oil.
Olea volatilia. Ed.Volatile Oils.
Volatile oils are prepared nearly in the same manner as thedistilled waters, except that less water is to be added. Seedsand woody substances are to be previously bruised or rasp-ed. The oil comes over with the water, and is afterwardsto be separated from it, according as it may be lighter thanthe water, and swim upon its surface, or heavier, and sinkto the bottom.
Besides, in preparing these distilled waters and oils, it is to beobserved, that the goodness of the subject, its texture, theseason of the year, and similar causes, must give rise to somany differences, that no certain or general rule can be gi-ven to suit accurately each example. Therefore many thingsare omitted, to be varied by the operator according to hisjudgment, and only the most general precepts are given.
Olea distillata. Lond.Distilled Oils.
The seeds of anise and caraway, the flowers of chamomileand lavender, the berries of juniper and allspice, the topsof rosemary, and the dried herbs of other articles, are tobe used.
Each of these is to be put into an alembic, and covered withwater, and the oil drawn off" by distillation into a large re-frigeratory.
The water which comes over with the oils of caraway, pep-permint, mint, allspice, and pennyroyal, in distillation, is tobe kept for use.
Dub.Let the oil be extracted, by distillation, from the subject pre-viously macerated in water, with the addition of as muchwater as may be sufficient to prevent empyreuma.