CHAP. XIII.
Of what is procured by Distillation.
By Distillation are procured Spirit, Essence, simple Waters and Phlegm.
Spirits are very difficult to be defined. I consider them as the most subtil and volatile Parts of a Body.
All Bodies without Exception have Spirits more or less.
These Parts are an ignited Substance, and consequently by their own Nature disposed to a violent Motion.
These volatile Particles are more or less disposed to separate themselves, as the Bodies are more or less porous, or abound with a greater or lesser Quantity of Oil.
By the Term Essence, we understand the oleaginous Parts of a Body. An essential Oil is found in all Bodies, being one of their constituent Principles. I have observed in all my Distillations, Spirit of Wine excepted, a soft unctuous Substance floating on the Phlegm; and this Substance is Oil, which we call Essence; and this is what we endeavour to extract.
Simple Waters are those distilled from Plants, Flowers, &c. without the Help of Water, Brandy, or Spirit of Wine. These Waters are commonly odoriferous, containing the Odour of the Body from whence it is extracted, and even exceeds in Smell the Body itself.
Phlegm is the aqueous Particles of Bodies; but whether an active or passive Principle, we shall leave to the Decision of Chemists.
It is of the last Importance to a Distiller to be well acquainted with its Nature; many mistaking for Phlegm several white and clouded Drops, which first fall into the Receiver, when the Still begins to work. These, however, are often the most spirituous Particles of the Matter in the Alembic, and consequently ought to be preserved. What has given occasion to this Mistake, is some Humidity remaining in the Head, &c. of the Alembic. And had it been thoroughly wiped, the first Drops would have been equally bright with any during the whole Operation.
The following Remark deserves Attention. In Bodies that have been digested the Spirits ascend first; whereas in Charges not digested, the Phlegm ascends before the Spirits. The Reason of this is very plain and natural.
In Substances previously digested, the Action of the Fire no sooner causes the Matter in the Alembic to boil, than the Spirits, being the most volatile Parts, detach themselves, and ascend into the Head of the Alembic. But when the Matter to be distilled has not undergone a proper Digestion, the Spirits being intangled in the Phlegm, are less disposed to ascend, till the Phlegm itself separates, and gives them room to fly upward. The Phlegm being aqueous rises first: This is more particularly observable in Spices. I am, however, inclined to believe, that were the Operation performed in an Alembic, whose Head was at a great Distance from the Surface of the Charge, they would not ascend high enough to come over the Helm, but fall back again by their own Gravity, and by that means leave the Spirits at Liberty to ascend. But in the common Refrigatory Alembic this always happens.
If this Observation be not readily admitted, I appeal to Experience, which I desire may be the Test of every thing I shall advance.
Another Observation, which has verified the above Assertion by innumerable Instances, is, that in an extraordinary Run of Business, when I had not time sufficient to digest the Substances, I used to bruise them in a Mortar; but notwithstanding the Trituration, the Phlegm first came over, and afterwards the Spirits. But I desire to be understood, that I speak here only of the volatile Parts of the Plants not drawn with vinous Spirits, but contained in a simple Water.
Another Remark I must add, and which I hope will be acceptable to the Curious, as it has not yet been made public, though doubtless the Observation has often occurred to others; it is this: That in mixed Charges, consisting of Flowers, Fruits, and aromatic Plants, put into the Alembic without a previous Digestion, the Spirits of the Flowers ascend first; and notwithstanding the Mixture, they contracted nothing of the Smell or Taste of the Fruits and Plants. Next after the Spirits of the Flowers, those of the Fruits ascend, not in the least impregnated with the Smell or Taste of either of the Flowers or Plants. And in the last Place the Spirits of the Plants distil no less neat than the former. Should this appear strange to any one, Experience will convince him of the Truth.
Another Observation I have made on aromatic Herbs, is, that whether they are, or are not digested; whether the Spirits or Phlegm ascend first; the Spirits contain very little of the Taste and Smell of the Plants from whence they were extracted; and I have always been obliged to put to these Spirits a greater or lesser Quantity of the Phlegm, in order to give the Spirits I had drawn the Taste of an aromatic Odour of the Plants; the Phlegm containing the greatest Quantity of both.
This Observation I insert as of great Use to those who practice Distillation.
As the Term Digestion often occurs in this Essay, I cannot avoid pointing out its Advantages, and even shew the Necessity of using it in several Circumstances.
Substances are said to be in Digestion, when they are infused in a Menstruum, over a very slow Fire. This Preparation is often necessary in Distillation; for it tends to open the Bodies, and thereby free the Spirits from their Confinements, whereby they are the better enabled to ascend.
Cold Digestions are the best; those made by Fire, or in hot Materials, diminish the Quality of the Goods, as some Part, as the most volatile, will be lost.
In order to procure Essences, the Bodies must be prepared by Digestion. It is even of absolute Necessity for extracting the Spirits and Essences of Spices.