The History of the Royal Society of London/Part 2/Paper 12
THE
HISTORY
Of Making
GUN-POWDER.
' Τhe materials of Gun-powder are Salt-peter, Brimstone, and Coal; the Peter and Brimstone must be both refined if you mean to make good Powder, and the Coal must be Withy and Alder equal parts; for Withy alone is counted too soft, and some do commend Hazle alone to be as good as the other two.
'The whole Secret of the Art consists in the proportion of the Materials, the exact mixture of them, that in every the least part of Powder may be found all the Materials in their just proportion; then the Corning or making of it into Grains; and lastly the Drying and Dusting of it.
'The proportion is very differently set down by several Authors; Baptista Porta tells us the ordinary Powder is made of four Parts of Peter, one of Sulphur, and one of Withy Coal: But the best Powder of 6, or 8 of Peter, and one a piece of the other, which agrees pretty well with Bonfadini a late Italian Writer, in his Book of the Art of Shooting flying, where, to make the best Gun powder, he prescribes seven Parts of Peter, one of Brimstone, and of Hazel Coal an ounce less in every pound: Cardan says; Constat ex tribus Halinitri partibus, duabus Saligni Carbonis atque una Sulphuris, Convenitque magnis Machinis; Sed Midiocribus Halinitri partes decem, Saligni carbonis tres, Sulphuris duas, parvis vero Halinitri partes decem; Carbonis ligni nucis Avellonæ sine nodis, tum Sulphuris partem unam singularem: Langius appoints three of Peter, two of Withy Coal, and one of Brimstone: The English Author of Fire-works, says, that the proportions in England to make good, indifferent, and ordinary Powder, is 5, 4, and 3 parts of Peter, to two of Coal, and one Brimstone. Our English Workmen are generally so curious of their secret, that I could not obtain the proportion of them without a promise of Secrecy: But when all is done their secret is not so much the way to make the best Powder, as the best way to get most money by it, by subtracting from the Peter, and making up weight with the Coal; when indeed there is so great a Latitude, that provided the Materials be perfectly mixt, you make good Powder with any of the proportions above-mention'd; but the more Peter you allow it, it will still be the better, till you come to observe eight Parts.
'The next thing after the proportion, is the mixture, about which most of the workmens time and pains is bestowed: For first in a Horse-mill with two stones (like that with which they grind their Materials at the Glass-house) moving upon a Marble bottom, which is edged with boards set sloaping, that what slips from under the stones may slide back again.
'They grind the Brimstone and Coal each of them apart by themselves as fine as possibly they can; then they sift each of them apart by themselves: The Brimstone is sifted thorough Tiffany in a Bolting mill, such as the Bakers use for Wheat-flour: the Coal is sifted thorough Lockram, in a bag made like a shirt sleeve; for the convenience of the Work-man it is done in a close Bin, with only two holes for him to put his arms in, and shake the bag about. Whatsoever of each material is not small enough to sift thorough, is brought again to the Mill to be new ground.
'As for the Peter, that must in the Copper be dissolved in as much water as will just take it up, and then the water must be boiled away till the Peter comes to the thickness of hasty-pudding. The reason of this operation is because when the Peter is thus soft, the other materials will the easilier incorporate with it, and in the next place it will not wear the wooden pestles so much when it comes to the Mill, as when it is hard and dry.
'When the Materials are in this readiness, they are weighed (only the Peter is weighed before it is put to dissolve in the Copper) and by proportion are carried to the mingling Trough, which is made of boards, like a great Chest without a cover, being about eight foot long, four broad, and three foot high. The Coal is laid in first, the Brimstone next, and the Peter at top of all; then two men with shovels stir and mingle them together for an hour, and then 'tis ready for the Mill.
'The Powder-mills are seldom made to move with any thing but water: The great water-wheel is made like that of an ordinary water-wheel, either over-shot or under-shot, according to the quantity of water they have: To the Axis of this wheel, a little way within the Mill is fastened a lesser wheel, called the Spar-wheel, with strong Cogs, which in their motion round take hold of the round staves of another wheel of about the same diameter, set a little way above it, and fastned to the end of a beam of 15 or 16 foot long, laid parallel to the Horizon, with an iron gudgeon at the other end of it, to facilitate its motion round: This beam is called the round beam; out of it come a certain number of arms of about nine inches long, and three inches broad, which in their going round meet with other lesser arms (called Tapes) coming out of the Pestles (for so they call certain small quarters of Timber placed perpendicular to the Horizon, about nine foot long and four inches broad; they are set in a slight frame to keep them steady); by these small arms the Pestles are lifted up about two foot and a half, and then let fall into a strong wooden Trough set under them, wherein the Powder is put to be pounded.
'Every Mill hath two Troughs, and about sixteen Pestles: every Pestle hath fastned to the lower end of it a round piece of Lignum Vitæ, of about five inches long and three and a half diameter; and into the bottom of the Trough, just where the Pestle is to fall, is let in another piece of Lignum Vitæ, of the fashion and bigness of an ordinary Bowl, split according to its longest diameter: The Pestles are not lifted up all together, but alternatively, to make the Powder turn the better in the working; and for the same reason round Troughs are counted better than square.
'To make excellent Powder, it ought to be wrought thus thirty hours; but of late they will not afford it above eighteen or twenty hours; once in eight hours they use to moisten the Powder with a little fair Water; others, who are more curious, put Water something thickned with quick-lime; others use White-wine Vinegar, others Aqua-vitæ: But if it be not moistned with something once in eight hours, the Powder will grow dry, and in half an hour after it will take fire. As soon as the Powder grows dry, you may find it, though at a distance, by the noise of the Mill; for then the Pestles will rebound from the bottom of the Trough and make a double stroke. The only danger to the Mill is not from the Trough; for many times the iron Gudgeons grow hot for want of greasing, and then the Dust that flies about will be apt to fire, and so the Mill blows up.
'From the Mill the Powder is brought to the Corning-house, of a middle temper between moist and dry. The way of corning it is with two hair Sieves join'd together, the upper Sieve inclosing some part of the Hoop of the lower Sieve: The upper Sieve hath holes of the size you will have the Powder grained at; the holes of the lower Sieve are much lesser: The upper Sieve they call their corning Sieve, the lower their wet Duster: They lay the Powder upon the upper Sieve some two inches thick; upon that a Piece of heavy wood made like a Trencher, of about eight inches diameter, and two and a half in thickness, called a Runner, which when the Sieve is moved, by its weight and motion, forces the Powder thorough the upper Sieve, and that corns it. Then the lower Sieve receives the Powder, and lets the dust go thorough the Bin, over which the Sieve is shaken, called the Dustingin.
'When the Powder is thus corned, it is laid about an inch and half thick on the drying Sieves, which are made of coarse Canvass fastned to slight frames of Deal about an Ell long, and some twenty inches broad; and thus it is carried into Stoves to dry.
'The Stove is commonly a little Room about eighteen or twenty foot square, with ranges of small Fir poles about two foot one above another, to lay the drying Sieves upon, but only on that side the fire is made. Besides a glass window to give light, there must be a small lover-hole at the top of the Room, to let out the steam, else the Powder will not only be the longer a drying, but often by the return of the steam on the Sieves, the top of the Powder will be so crusted that the lower part will not dry. The Room is heated by an Iron about a yard high and half a yard broad, cast in the form of an Arch, equal to a Semi-quadrant, and placed in the back of a Chimney, the fore part whereof is like a Furnace; and to avoid danger, opens into another little Room apart, called the Stoke-hole.
'The Powder is brought into the Stove before it be heated, and is not taken out again till the Stove be cold; and about eight hours is required to the drying of it. In hot Countries the Sun is the best Stove, and a great deal of danger and charges that way avoided.
'After the Powder is dried, it is brought again to the Corning-house, where it is again sifted over the Dusting bin in other double Sieves, but without any Runners. These Sieves have both of them smaller holes than the former: The upper Sieve is called the Separater, and serves to divide the great corns from the lesser; the great corns are put by themselves, and serve for Cannon Powder. The lower Sieve is called the Dry-duster, and retains the small corns (which serve for Musquet and Pistol) and lets fall the dust into the Bin, which is to be mingled with fresh Materials, and again wrought over in the Mill.
'So that good Powder differs from bad (besides the well working and mingling of the Materials) in having more Peter and less Coal; and lastly, in the well dufting of it.
The last Work is to put the Powder into Barrels; every Barrel is to contain five score weight of Powder, and then 'tis ready for sale.
