Elements of the Theory and Practice of Chymistry, 5th ed.

by Pierre Joseph Macquer

OBSERVATIONS.

The design of this operation is to incorporate and unite an Oil with a Volatile Alkali. Spirit of Wine is added in the distillation of the Volatile Salt, intended for this purpose, in order to prepare it for receiving the Oil, and combining more easily therewith. This Salt hath the property, as was shewn in the preceding operation, to carry up with it part of the substances with which it is distilled. On this occasion therefore, it is impregnated with a little of the Spirit of Wine; and this Spirit, which contains in itself an oily matter, and is the solvent of Oils, cannot fail to facilitate the union of the Oil with the Volatile Salt, as it serves for a medium between them. Yet it must not be considered as a necessary one. A Volatile Salt, sublimed with Salt of Tartar alone, would also very readily take up any Oil with which it should be distilled. We have seen that Volatile Alkalis are originally impregnated with much Oil, which is radically dissolved in them; and consequently they have a great affinity with that substance. So that if we distil them with Spirit of Wine, at the beginning of this operation, we do it not out of any necessity, but only with a view to accelerate or facilitate the intended union.

In this distillation the Volatile Alkali always rises first, and before the Spirit of Wine; which proves that it is much more volatile, though it be more ponderous than the Spirit.

If the Spirit of Wine used in this distillation be very aqueous, it will dissolve the Salt as it comes over, and will reduce it into a Spirit: but if, on the contrary, it be well dephlegmated, the Volatile Alkali will remain in a concrete form, and will not be dissolved in this first distillation.

If you desire to have the Volatile Salt entirely dissolved in the Spirit of Wine, though highly dephlegmated, it must be repeatedly distilled a great number of times with the same Spirit of Wine: for, though the small quantity of Spirit of Wine, with which it unites in the first distillation, be not capable of reducing it into a liquid, yet, as it takes up more and more every time it is distilled, it dissolves at last, and then with the Spirit of Wine forms a fluid that appears perfectly homogeneous. The Volatile Alkali is now rendered considerably milder by the union thus contracted, and is accordingly called the Dulcified Volatile Spirit of Sal Ammoniac.

When well dephlegmated Spirit of Wine is mixed with a Volatile Spirit of Sal Ammoniac, perfectly saturated with Volatile Salt, these two liquors together immediately form a white opaque coagulum. But for this purpose you must not use a Volatile Spirit distilled with Lime; for then the experiment will not succeed.

This coagulum does not seem to be the effect of an intimate union between the two substances mixed together, like that which results from the union of a Fixed Alkali with an Oil. It hath just now been shewn that Spirit of Wine and a Volatile Alkali do not readily unite together. I believe the effect rather depends on this, that Spirit of Wine hath a greater affinity than the Volatile Salt with water; and therefore the Spirit, which ought to be perfectly dephlegmated, attracts the water wherein the Volatile Salt was dissolved, which thereupon recovers its concrete form; and being at that time mixed with the Spirit of Wine, it keeps that Spirit locked up among its parts, and hinders it from appearing with its natural fluidity.

What confirms this notion is, that the coagulum, which at first seems to make but one whole, soon separates into two parts, whereof one, which is solid, and nothing but the Volatile Salt concreted, lies at the bottom of the vessel; and the other, which is fluid, cannot be mistaken for any thing but the Spirit of Wine, which, being disengaged from the particles of Salt, recovers the form of a liquid, and, being the lightest, floats over the Salt. Yet these two substances, though now very distinct from each other, are not so pure as before they were mixed together. The Spirit of Wine hath dissolved a little of the Volatile Salt; and, on the other hand, the Volatile Salt retains a little of the Spirit of Wine. They may indeed be perfectly united and blended with each other, by the method above delivered; that is, by being frequently distilled and cohobated together, till they form one mixt; but then that mixt will be in a liquid form.

The first time this mixture is distilled, a great deal of Volatile Salt rises first, which is very fit to unite with an Essential Oil, and so to become a Volatile Oily Aromatic Salt.

THE END.