And this is the best Method of preparing simple Waters, provided the two sorts be not mixed together, for both of them would be spoiled by such a Mixture.
Hence it plainly appears at what time, with the same Degree of Fire, quite contrary Virtues may arise from a Plant; for so long as a milk Water continues to come over from such Plants as are aromatic, so long the Water remains warming and attenuating; but when it comes to be thin and pellucid, it is acid and cooling.
Hence we may also learn the true Foundation for conducting of Distillation; for if the Operation be stopped, as soon as ever the white Water ceases to come over, the Preparation will be valuable and perfect; but if, through a Desire of increasing that Quantity, more be drawn off, and the latter acid Part suffered to mix with the first Running, the whole will be spoiled, or at least rendered greatly inferior to what it would otherwise have been.
Such is the general Method of procuring simple Waters, that shall contain the volatile Virtues of the Plants distilled; some Rules are however necessary to render it applicable to all Sorts of Plants; these Rules are the following:
1. Let the aromatic, balsamic, oily, and strong-smelling Plants, which long retain their natural Fragrance, such as Balm, Hyssop, Juniper, Marjoram, Mint, Origanum, Penny-royal, Rosemary, Lavender, Sage, &c. be gently dried a little in the Shade; then digest them, in the same manner as already mentioned, for twenty-four Hours, in a close Vessel, with a small Degree of Heat, and afterwards distil in the manner above delivered, and thus they will afford excellent Waters.
2. When Waters are to be drawn from Barks, Roots, Seeds, or Woods that are very dense, ponderous, tough and resinous, let them be digested for three, four, or more Weeks, with a greater Degree of Heat, in a close Vessel, with a proper Quantity of Salt added, to open and prepare them the better for Distillation. The Quantity of Sea-salt is here added, partly to open the Subject the more, but chiefly to prevent Putrefaction, which otherwise would certainly happen in so long a Time, and with such a Heat as is necessary in this Case, and so destroy the Smell, Taste, and Virtues expected from the Process.
3. Those Plants which diffuse their Odour to some Distance from them, and thus soon lose it, should immediately be distilled after being gathered in a proper Season, without any previous Digestion; thus Borage, Bugloss, Jessamin, white Lilies, Lilies of the Valley, Roses, &c. are hurt by Heat, Digestion, or lying in the Air.
CHAP. III.
Of increasing the Virtues of Simple Waters by means of Cohobation.
By Cohobation is meant the returning the distilled Water procured in the manner described in the preceding Chapter, upon more of the fresh Plant. The Operation is performed in the following manner:
Take the Plant and Liquor remaining in the Still after the Operation described in the foregoing Chapter is performed, and press them strongly in a Bag for that Purpose, that all the Decoction may be obtained; and with this mix all the Water before drawn over. Return this Mixture into the Still, and a fresh Quantity of the same Plant, and if necessary, as much Water as will make the former Proportion to the Plant. Close all the Junctures exactly, and digest the whole in a gentle Degree of Heat for three Days and three Nights, that the Herb, being so long steeped in its own Liquor, may be opened, loosened, and disposed the easier to part with its Virtues. This Digestion is of great Service; but if protracted too long, introduces a Change tending to Putrefaction. Let the Water now be distilled off, in the same manner as before; only proceeding more cautiously, and somewhat more slowly at first; because the Liquor in the Still being now thicker, more impregnated with the Plant, and therefore more apt to smell upon feeling the Fire, it easily boils over; but after about half of the expected Water is come off, the Fire may be gradually raised.