If so be you haue at any time diuers sorts of Gunpowder, and it is your desire to know which of them is the strongest, then you must prepare a box, as A, B, being foure inches high, and about two inches wide, hauing a lid ioynted unto it. The box ought to be made of iron, brasse, or copper, and to bee fastned unto a good thick plank, and to haue a touch-hole at the bottom, as O, and that end of the box where the hinge of the lid is, there must stand up from the box a peece of iron or brasse, in length answerable unto the lid of the box: this peece of iron must haue a hole quite through it, towards the top, and a spring, as, A, G, must bee screwed or riueted, so that the one end may couer the sayd hole. On the top of all this iron, or brasse that standeth up from the box, there must bee ioynted a peece of iron (made as you see in the figure) the hinder part of which is bent downward, and entreth the hole that the spring couereth; the other part resteth upon the lid of the box. Open this box lid, and put in a quantity of powder, and then shut the lid down, and put fire to the touch hole at the bottom, and the powder in the box being fired, will blow the box lid up the notches more or lesse, according as the strength of the powder is: so by firing the same quantity of diuers kindes of powders at seuerall times, you may know which is the strongest. Now perhaps it will bee expected that I should speak of the making of Saltpeter, Gunpowder, Coales, with the refining of Sulphur: but because they are so commonly to bee had, and to bee bought at better rates than I know they can bee made by any that intend it for their priuate use, I haue forborne it: There are diuers I am sure that would willingly bee in action: I haue thought fitting therefore to set downe the collection of naturall Saltpeter, which is a kinde of white excrescence growing upon stone-wals, and (as I haue seene great store) in the arches of stone-bridges. First therefore gather this white excrescence, and adde unto it Quick-lyme, and Ashes, mingle them, and put them into a halfe-tub that hath a hole to draw the liquor out at; then put into this halfe-tub warm water, and let it stand untill all the peter be dissolued; let it then drain out at the hole by little and little, and if the liquor be not cleere, double a brown paper, and put it within a tunnell, and straine the liquor through it. Then boyle it and scum it untill it bee ready to congeale, neither too hard, nor yet too tender: then take it from the fire, and put it into shallow vessels, either of earth or brasse; set them in a cold place two or three dayes, and it will shoot into isicles, and this is called Rochpeter. Thus much for the ingredients. Now I am come unto the Formers, the number whereof I cannot certainly determine, because it dependeth upon the variety of each particular persons inuention. Now that I may formally proceed, I will first make some distinction of each kinde in generall; and then I