The instruments chiefly used in the distillation of simple waters are
of two kinds, commonly called the hot still, or alembic, and the
cold still. The waters drawn by the cold still from plants are much
more fragrant, and more fully impregnated with their virtues, than
those drawn by the hot still or alembic.
The method is this:—A pewter body is suspended in the body of the
alembic, and the head of the still fitted to the pewter body; into
this body the ingredients to be distilled are put, the alembic filled
with water, the still-head luted to the pewter body, and the nose
luted to the worm of the refrigeratory or worm. The same intention
will be answered by putting the ingredients into a glass alembic, and
placing it in a bath-heat, or balneum mariæ.
The cold still is much the best adapted to draw off the virtues of
simples, which are valued for their fine flavour when green, which is
subject to be lost in drying; for when we want to extract a spirit
from plants so light and volatile, as not to subsist in open air any
longer than while the plant continues in its growth, it is certainly
the best method to remove the plant from its native soil, into
some proper instrument, where, as it dies, these votile parts may
be collected and preserved. And such an instrument is what we call
the cold still, where the drying of the plant, or flower, is only
forwarded by a moderate warmth, and all that rises is collected and
preserved.