Page:History of the Royal Society.djvu/300

 the whiter, and Rock the better; you must take great care all this while the Fire be not too strong, for while this is doing, the Liquor will be apt to boil over, and will not easily be appealed without your great loss.

'When this is done, lade out the Liquor into a settling Tub, and cover it over with a Cloth, that it cool not too soon, and within an hour or two, a thick yellow Fæces will fall to the bottom of the Tub; then quickly draw off the Liquor while it is hot, into the shooting Trays or Pans, and do as you, did in making Peter, saving, that you must cover the Trays with a Cloth, for then the Liquor will begin to shoot at the bottom, which will make the Peter-Rock into much fairer Chrystals, than otherwise it would: When no more Peter will shoot (which is commonly after two days) pour off the Liquor that swims at the top, and put the Peter into a Tub with a hole at the bottom for to drain, and when it is dry, it is fit for use.

'The Figure of the Chrystals is sexangular, and if it hath rightly shot, is fistulous and hollow like a Pipe.

'Before I proceed to tell you, how this darling of Nature (the very Basis and Generation of Nutriment) is converted into Gun-powder (the most fatal Instrument of Death that ever Mankind was trusted withal) I will crave leave to acquaint you with a few Speculations I have of this Salt, which if I could clearly make out, would lead us into the knowledge of many noble Secrets in Nature; as also to a great improvement in the Art of making Salt-peter.

'First then you are to observe, that though Peter go alway in Gun-powder, yet if you fulminate it Rh