Take of Frankincense or Mastick powdered small, as much as will serve to fill the third part of a Retort (which must be coated) upon which pour a sufficient quantity of spirit of Salt, taking heed that the Retort be not filled too full, or else the spirit when it boyles, flows over it, then place it in sand, and give fire by degrees, and there will first come out some phlegme, after which a clear transparent oyle together with the spirit of salt, which must be kept by it self, after this a certain yellow Oyle which must be received by it self, and last of all there follows a red Oyle, which altho’ it is not to be cast away, yet it is very unlike to the first, serving for outward uses, and to be mixed with Oyntments and Emplasters, for it doth wonderfully consolidate, and therefore good in new and old Wounds. The first being well rectified, is in its subtilty, and penetrating faculty not unlike to spirit of wine, and may profitably be used inwardly and outwardly, _viz._ in cold affects, but especially in the stiffness of the Nerves, caused by cold humors, upon which follows a contraction; but then you must first rub the member contracted with a linnen cloath, that it may be well warmed, into which then the Oyle must be chafed with a warm hand. For it doth do wonders in such like affects of the Nerves. After the same manner may Oyles be made out of all gumms. The red, tenacious and stinking Oyles of Tartar, Harts-horn, Amber, _&c._ distilled after the common way by retort are also rectified with spirit of salt so as to become transparent and to lose the _Empyreuma_ contracted by distillation. Now the cause of the blackness, and fetidness of these kind of Oyles, is a certain volatile salt which is to be found as well in Vegetables, as certain Animals, which is easily mixed with the Oyle, and makes it of a brown colour. For every volatile salt whether it be of Urine, Tartar, Amber, Harts-horn, and of other Vegetables and Animals, is of this condition and nature, as to exalt, and alter the colours of sulphureous things, and that either for the worse or for the better: but for the most part it makes Oyles thick, black and stinking, as you may see in Amber, Harts-horn, and Tartar. The cause therefore of the blackness, and fetidness of these Oyles being known we may the more easily take heed thereof in distilling, and being contracted, correct them again by the help of spirit of Salt. For all volatile salt hath contrariety to any acid spirit, and on the other side, every acid spirit hath a contrariety with all volatile salts, that have the nature of salt of Tartar. For metals that are dissolved with acid spirits are as well precipitated with spirit of Urine, or any volatile salt as with the liquor of salt of Tartar; which shall be more at large declared in the second part.