The construction therefore of the furnace being in my opinion clearly shewed, there now follows the manner of distilling, and subliming with it.
Although haply, and contrary to my hope any obscurity should be met withal, yet one process will explain another: and the diligent operator, and searcher of Nature shall without doubt, by his practise attain the effect after the same manner as I have prescribed: which together with the blessing of GOD, I heartily wish all pious Chymists, Amen.
How the Spirit of Salt is to be distilled.
The reason why I enter upon the spirit of salt, before I say any thing of the spirits of vegetables, is this, viz. because it is even the chiefest, which can be made in this furnace: for few exceed this in strength and vertues; wherefore I also have given it the preeminency. Neither is there any of the acid spirits, about which the Chymists hitherto have been more busied, than this, wherefore also it is of all, of greatest price, &c. for some have mixed salt with potters clay, and have made this mixture into little balls, which they have to get the spirit, forced by retort in a very strong fire: some have mixed salt with bole, some with the powder of tyles, others with burnt Allume, &c.
Others using a more compendious way have made salt to flow in a retort, which hath a pipe both in the upper, and hinder part; by the uper pipe of which they have dropped in cold water, to elevate the ponderous spirits of the salt, but by the hinder they have blown with Bellows, to force the spirits into the retort: and this way is not altogether to be slighted, yet it hath this inconveniency, that in process of time the retorts are broken that they can no longer retain the salt, and so the distillation is intercepted. Some have attempted it with Iron retorts, but by this means the spirits have been deaded, because they easily set upon the Iron, whence instead of spirit they have had flegme. And such, and other tedious wayes of distilling they have invented; and by the best of them indeed they could scarce distill one pound in 25. or 30. hours space with 50. 60. or 100 pound of coals; this being the reason, because the salt is very little wrought upon, and therefore it is that few ever had the spirit right and good, whence also the vertues thereof have been unknown.
And this therefore I was willing to make known, that it might appear, what price this spirit hath hitherto been of, and how easie, and abundantly, and with what little cost, it may after my new invented way be made.
It is said above, that the materials may in this way of distilling be immediately cast into the fire; yet this must be wisely understood. For although some of the species may without any preparation be immediately cast into the fire, yet it doth not follow that all and every one of them must: for in some of them we must use our discretion, as in the distilling of salt. For if the salt be immediately cast into the fire, it will not only yield no spirits, but will leap so long upon the coals, until it find a descent to the lowest part of the furnace: Now this may be prevented divers wayes; and first indeed after this manner: Dissolve salt in common water, then quench burning coals with this water, that they may be impregnated with the salt, which afterwards set on fire in the furnace: but you must first cast in other burning coals, upon which you must cast those that are impregnated with salt untill the furnace be full, as is above said: and while the coals burn, the salt is resolved by the force of the fire into spirit.
Now you must observe that he that distils spirit of salt after this manner, must make choice of glass receivers, because the spirit whilest it is hot, penetrates by reason of its wonderful subtilty, those that are earthen. And this spirit is of a most grateful taste. But in defect of glass receivers, I shall shew you another way wherein you may use those that be of earth.
Mix salt, and vitriol or allome together, grinding them very well in a Morter (for by how much the better they are ground, the more Spirit they yield.) Then cast this mixture into the fire with an Iron Ladle, viz. so much of it as will be sufficient to cover the coals, and then with a great fire the spirits come forth into the receivers, where being coagulated, they distill down into the dish, and thence into another receiver. And if thou knowest how to work aright, the spirits will like water continually run out thorow the pipe, the thickness of a straw; and thou mayest easily every hour make a pound of the spirit. Now the reason why thou shalt by this way have more spirits than by the other, is this, viz. because the vitriol and allome, which is mixed with the salt, makes it flow quickly, by which means it is prevented from falling down through the coals to the lower part of the furnace, but sticking to the coals is almost all of it turned into spirits. The Caput Mortuum, which is reddish, easily falls with the ashes through the grate, and can no more be distilled, but yields by excoction a white fixed salt, which serves for the flowing of metals; and being dissolved in warm water serves also for a glyster against the Worms, which it kills, and purgeth also the Bowels.