It may be asked: why _lapis calaminaris_, Zinck and unquencht lyme, calcined tartar, salt of potashes, fixed salt nitre or the like things prepared by the fire, must be added unto salt Armoniack, and whether it be not as good to add some bolus, or other earth (as usually is done to other salts) and so to distil a spirit of it? To which I answer, that there are two sorts of salt in salt Armoniack, _viz._ a common acid salt, and a volatile salt of urine, which without mortifying of one of them, cannot be separated: for as soon as they feel the heat, the volatile salt of urine carrieth the acid salt upwards, and they both together yield a sublimate, of the same nature and essence with common salt armoniack which is not sublimed, onely it is purer than the common. And no spirit would come over from it, if it should be mingled with bole, brick, dust, sand, or any other strengthless earth, and so distilled, but the whole salt as it is of it self (leaving its earthy substance behind) would sublime thus dry: but that it falleth out otherwise with the _lapis calaminaris_ (which is also like an earth) so that a separation of the salts is wrought thereby, and a volatile spirit cometh over; the reason is, that the _lapis calaminaris_ and Zinck are of such a nature, that they have a great affinity with all acid things, and do love them, and are loved by them likewise (whereof some mention hath been made in the first part) so that the acid salt sticks to it in the warmth, and uniteth it self with it, and the volatile salt is set free, and distilled into a subtle spirit; which could not have been done, if the acid salt had not been kept back, by the _lapis calaminaris_ or Zink. But that a spirit is distilled off by addition of fixed salts; the reason is that fixed salts are contrary unto acid salts, and (if they get the uperhand) do kill the same, and rob them of their strength, whereby those things which are mixed with them are freed from their bond: and so it falls out here with salt armoniack, that when by addition of a vegetable fixed salt, the acidity of the salt armoniack is killed; the salt of urine, which formerly was bound therewith, gets its former freedome and strength, and being sublimed turns into a spirit. Which could not have been done, if common salt had been added to the salt armoniack instead of salt of tartar; for the salt of urine would thereby (as by a far greater enemy) be killed and kept back, so that it could yield no spirit. I thought fit to give notice hereof to the ignorant (not for those, who knew it before) and to the unknowing it will do much good, and that they may have a light for other labours: for I have many times seen, and see it still by daily experience, that the most part of vulgar Chymists, whatsoever they do (having got it either by reading, seeing, or hearing) they hurle it over like botchers, and are not able to give any solid reason, why this or that must fall out in such or another