THE efficient cause for expelling the Shot is the Fire that is made of Powder, that is compounded of Salt-Petre, Brimstone and Charcoal.

The Salt-Petre gives the Blow or Report.

The Sulphur takes Fire, and the Coal rarifies the other two, to make them Fire the better.

Two sorts of Gun-Powder are commonly in use.

One is made of five Parts of Salt-Petre, one of Brimstone, and one part of Charcoal.

The other (being stronger) is made of six one and one.

That of five one and one is generally used for great Guns, the other for Muskets and small Arms.

And it hath been generally observed, that forty two pound of Powder of five one and one, is stronger than forty five pound of four one and one ; and forty pound of six one and one works greater effect, than forty two pound of five one and one, although all contain thirty pound of Salt-Petre.

Anciently they made Powder of four one and one ; but this Powder by experience being found too weak, is not now in use.

That Powder which at this day is received into their Majesties Magazine at the Tower of London, is made of six one and one.

1. The harder the Corns are in feeling, by so much the better it is.

2. When the Powder is of a fair Azure or French Russet colour, it is judged to be a very good sort and to have all its Ingredients well wrought, and the Petre to be well refined.

3. Lay five or six Corns upon a white piece of Paper three fingers distance one from another, then fire one, and if the Powder is good they will all fire at once and leave nothing but a white chalky colour on the Paper ; neither will the Paper be toucht: But if there remains a grossness of Brimstone and Petre, it discovers the Powder to be bad.

And take this for a general Rule, for a sign of good Powder; that which gives fire soonest, smoaks least, and leaves least sign behind it, is the best sort of Gun-Powder.

To preserve good Powder, Gunners ought to have that reason to keep their Store in as dry a place that can be had in the Ship, and every Fortnight or three Weeks to turn all the Barrels and Cartridges upside down, so that the Petre may be dispersed to every part alike ; for if it stands long, the Petre will always descend downwards, and if it be not well shak'd and moved, it will want of its strength at the top, and 1 l. at bottom with long standing will be stronger then 3 at the top.

TO find the strength of Guns the brief Rule is thus, First find the Diameter of the bore (or Chamber of the Gun) where the shot lies, then the true fortified Iron Guns ought to be 11 of those Diameters in the circumference of the Gun at the Touch-hole, 9 at the Trunions, and 7 at the Neck, a little behind the Mouth or Muzzle-ring where the dispart is set.

But Brass Guns having the same weight of Powder are as strong at nine Diameters of the Chamber bore about the Gun at the Touch-hole, and seven Diameters at the Trunions, and five at the Neck.

This is the Rule of the true bored and true fortified Guns ; and for those more or less fortified, observe the Proportions in this following Table.

Weight of Powder for Service is proportioned by the Numbers of Diameters of the Bore about the Gun at the Touch-hole, for such Guns so qualified as in the foregoing Table, viz., and to load them accordingly.

Measure the length of the Cylender from the Muzzle to the Britch, and divide the Length by 7, and divide the Quotient by 3, and the Product will shew how many the Trunions must stand from the bottom of the bore of the Piece, and that they ought to be placed so that 2/3 of the Piece may be seen above the Center of the Trunions.

The Essential Ingredients for making Gun-Powder are three, viz. Salt-Petre, Brimstone and Charcoal, and of these there are to be three several quantities and proportions, according to the use intended for; and for the best Powder that is now made, there is commonly used these proportions.

The Cannon Powder hath commonly of Salt-Petre four times so much as of Brimstone and Charcoal, and for Musket Powder it is usually made five times as much Salt-Petre as of Brimstone and Coal.

Now having the Proportional quantity of each of these Ingredients, put all the Salt-Petre together into a Caldron, and boyl it with so much Water as will serve to dissolve it with ; being so dissolved, it ought to be washed and lay'd upon a clean place; this done, beat the quantity of Coal into dust, then put this Charcoal dust being finely beaten into the disolved Petre, and incorporate them very well together, and as you mingle them, put in by little and little the Sulpher very well beaten; when this mixture of Salt-Petre Brimstone and Coal are well incorporated, lay it forth to dry a little ; when the same mixture is somewhat dryed and is very well mixed, sift it well through a Sieve ; then casting Water or Vinegar upon it, corn it, and when you have so done, dry it against the Fire and the Gun-Powder is made : There are divers ways to grind Gun-Powder ; the best way is to stamp it in Mortars with a Horse-mill or Water-mill, for the Powder is thereby most finely beaten and with least labour ; and to know if it be well done, you may with a Knife cut in pieces some of thie Composition, and if it appear all black it is well done, but if any of the Brimstone or Petre is seen, it is not incorporated enough.

The manner to sift Powder is thus,

Prepare a Sieve with a bottom of thick Vellom or Parchment, made full of round holes, then moysten the Powder which shall be corned with Water, put a little Bowl into the Sieve, then sift the Powder so as the Bowl rowling up and down in the Sieve may break the clods of Powder, and make it by running through the little holes to corn.

Having moistned the said Gun-Powder with Vinegar or fair Water, beat it well in a Mortar, then sift it through a Sieve or fine Searce; for every l. of Gun-Powder mingle one Ounce of Salt-Petre that hath been pulverised, and when you have so done beat and moisten this mixture again, until by so breaking or cutting with a Knife, there is no sign of Salt-Petre or Brimstone in it: Also corn this Powder when it is incorporated with the Petre, as it ought to be, and you have done.