The art of gunnery. Wherein is described the true way to make all sorts of gunpowder, guu-match [sic], the art of shooting in great and small ordnance: excellent ways to take heights, depths, distances, accessible, or inaccessible, either single or divers distances at one operation: to draw the map or plot of any city, town, castle, or other fortified place. To make divers sorts of artificiall fire-works, both for war and recreation, also to cure all such wounds that are curable, which may chance to happen by gunpowder or fire-works. This treatise is composed for the help of all such gunners and others, that have charge of artillery, and are not well versed in arithmetick and geometry : all the rules and directions in this book, being framed both with and without the help of arithmetick. By Nathanael Nye mathematician, master gunner of the city of Worcester.

CHAP. 16.

How to make an Engine to finde what propor∣tion of strength one kinde of powder is in comparison of other powder.

THe lid of this Engine is made to rise up in a straight line, and is as big as the box, and also hollow; on each side of the lid or cover, is a small hole for a wyre to pass through, and on one of the pillars of the Engine are little pieces of brass, or steel, so fitted that they may rise with a touch, and give way to the rising of the lid, and so soon as it is past, will hold it there, and will not suffer it to pass back

again; the form whereof is here presented.

[illustration] labeled diagram of engine described in chapter 16

H

G G

D E

F

F

G E

C

B

A

A The foot whereon the Engine standeth.

B The powder box, which hath too small wyres passing from each side to the top, to keep steddy the lid in its motion.

D The lid, which hath also two holes on each side for the wyres to pass through

E the side of the Engine, which is divi∣ded, on which is placed at every division, one of those Pieces to slide up and catch the lid.

FF The form of these catches, being either of steel or brass.

GG The too wyres that guide the box lid, and must be put into a little piece of brass, at the top, which may be screwed higher or lower at pleasure, for the better straightning of the same.

H The screw which straightneth those wyres, placed on the top.

The use of this Engine.

Take about one dram of such a sort of powder as you esteem to be the best of all others, and put it into the box, after it is co∣vered with the lid, at the touch-hole, which is in the bottom of the box, fire it with a

red hot wyre, being first primed with powder dust; then observe how high and to what division it ascends, which being noted down, take just so much powder of a courser sort, and try that in like maner as you did the former; then by noting up to what degree it ascendeth to, you may perceive the just difference between your best and worst powder; and by the same order of any other sort, as you shall desire to know its strength, and have occasion to use.

But in the next Chapter, I shall describe some other ways, because every man can∣not come by a good instrument to try the just strength of any powder.