In a desperate Case, like that of a large Quantity of rectified Spirit taking Fire, if Time permit, the Communication of the Beak of the Alembic with the Recipient, which is usually a Cask, must be cut off, by closely stopping the Bung; and be sure no Candle come near the Receiver, leaving the rest, as the Danger would be too great to expose ones self to the Flames of a large Charge, and the Distiller’s Safety should be principally considered.
I thought it my Duty to give my Reader these Informations, and hope that in the Practice of Distillation, he will find them of great Advantage.
CHAP. IX.
On the Necessity of often cooling the Alembic, as another Means of preventing Accidents.
The Refrigerant is so essential a Part of the Alembic, that for want of it several other Expedients are made use of to perform its Office, for cooling those whose Capacity, Brittleness, or lastly the Construction, will not admit of their having any.
The Refrigerant is usually in proportion to the Capacity of the Alembic, for which the following may serve as a Rule, that the Capacity of the Refrigerant should be to that of the Alembic, as 14 to 8.
The Necessity of cooling the Head of the Alembic is self-evident to all who have the least Knowledge of Distillation, as it condenses the Spirits, cools them, and causes them to flow into the Receiver, which, if of Glass, would otherwise be broken by the Heat; and consequently serves to prevent Conflagrations.
The Alembics of the Balneum Mariæ, and the Vapour Bath, ought also to have Refrigerants, like the common Alembic, unless they are of Glass.
Those of Earth and Glass are cooled, as we have already observed, with a wet Cloth, which is also used to cool the Head of other kinds of Alembics. But it is not difficult to contrive one which may be placed in a Refrigerant; such as the following.
To a common small Still apply and lute a Worm, or long tin or pewter Tube, forming several Circumvolutions, of the same Circumference with the Body, in order to give it some Elevation, place this Worm in a Refrigerant, proportioned to the Alembic. If the Capacity of this Alembic should make it bear too much on the Neck of the Matrass, it may be supported by a Trevit of the same Circumference as the Body itself: The Extremity of the Worm may have a Beak projecting beyond the Side of the Refrigerant, for conveying the Spirits into the Receiver.
This Apparatus will be attended with little Expence, will save the Distiller the Trouble of being perpetually cooling the Head of the Alembic, and is such a Safe-guard against Accidents, that if the Worm be well luted, nothing need be apprehended but from the Violence of the Fire.