Fleta minor the laws of art and nature, in knowing, judging, assaying, fining, refining and inlarging the bodies of confin'd metals : in two parts : the first contains assays of Lazarus Erckern, chief prover, or assay-master general of the empire of Germany, in V. books, orinally written by him in the Teutonick language and now translated into English ; the second contains essays on metallick words, as a dictionary to many pleasing discourses, by Sir John Pettus ... ; illustrated with 44 sculptures.

CHAP. VIII. How to cleanse the great Graind and black Salt-Petre Salt.

[Section. 1] THE black or grey Salt-Petre Salt, which is found (in boyling Salt-petre) below in the Kettle and slender-Tub, this may be good Salt for dressing Victuals, with∣out any danger, only it must first be cleansed and purified thus: Wash well the Kettle, put in clean Well-Water, make under it a fire, and when it begins to boyl, take the said Salt, put it gently in, and let it dissolve, stir it continually, and when 'tis all dissolved, then pour the Lees into a Tub, let it set∣tle that the Lees may be clear, then wash the Kettle clean again, put the clear Lees or Suds in it, and boyl it till the Salt fall in it, and then lift it out with the great Spoon, put it in a Basket above the Kettle, that the remaining Lees may run again into the Kettle, and lift up such Salt, un∣till no more will fall, then dry it, and so it is prepared: But some before they use it, let the Salt glow out, by which it becomes stronger, and what remains of the Lees in the Kettle, boyl it like the other Suds to a Lees, and put it out, and let the Salt-Petre grow out of it, for this Salt coming out of Salt-Petre, cannot be quite without Salt-Petre, but there will be still some among it, which is to be cleansed off thus.

Take Notice if the Salt have too much Salt-Petre, or [Section. 2] be very black and unclean, the Salt will not become very white at once, for when the Lees begins to be strong, then

ascends not white, therefore such unclean Salt must be dis∣solved in the Kettle once more, purified and cleansed, and then it will become very white.

[Section. 3] There is another way of cleansing such black and un∣clean Salt, viz. one may put the dissolved Salt out of the Kettle thus warm, through the Ashes, over which already Lees hath been put, of which the salt Lees, will almost purify and cleanse it self, yet it becomes not all white Salt, but the last remains commonly yellow, there∣fore it must be cleansed once more; likewise take notice, that when the Salt is to be put over the Ashes, that it must be well watered out, that the red bottom may not be very salty, else it will come in the next strong Lees, and makes it very salt.

And thus you have a true large Instruction of the Salt-Peter boyling, how it is to be usually observed; but it is a tedious and not profitable boyling for this reason, be∣cause there is in a Centner of Lees but three or four pounds of Salt Petre, therefore the Water remaining must all be boyled off, which takes much time and expences, and cannot be avoided, but how it may be helped (as I my self have found out and used) I will Demonstrate in the next Chapters.

Notes

• The uses of it.
• To make it white.
• To purify the Salt through A∣shes.