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A61158
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The history of the Royal-Society of London for the improving of natural knowledge by Tho. Sprat.
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Sprat, Thomas, 1635-1713.; Cowley, Abraham, 1618-1667. To the Royal Society.
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1667
(1667)
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Wing S5032; ESTC R16577
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253,666
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459
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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 thorow Tiffany in a Bolting-mill such as the Bakers use for wheat-flower The Coal is sifted thorow 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 thorow 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 boyled 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 't is 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 fastned a lesser wheel called the Spar-wheel with strong Cogs which in their motion round take hold of the round slaves 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 armes 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 Vitae 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 Vitae 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-vitae 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 stroak 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 joyn'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 thorow the upper Sieve and that corns it Then the lower Sieve receives the Powder and lets the dust go thorow into a Bin over which the Sieve is shaken called the Dusting-Bin When the Powder is thus corned it is laid about an inch and half thick on the drying Sieves which are made of course Canvase 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 Firr 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 Rome is heated by an Iron of about a yard high and half a yard broad cast in the form of an Arch equal to a Semy-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
whence the Bullet might casually receive some lateral impulse from the nose of the peece at the parting from it 2. The yielding of the Table which was sensible 3. The difficulty of aiming well by the Sight and Button so far from the Mark. Therefore to avoid all these the Experiments I caus'd to be made before you in the Gallery of this Colledge you may be pleased to remember were performed first taking only eight grains of Powder for the charge Secondly laying the Engine upon the floor and thirdly aiming by a thread at M a mark about an Inch and ¾ from the mouth of the Gun the edge of a knife being put for the mark the better to discern the line that was shot in and they thus succeeded When the piece was fastned to the floor both at R and L the Bullet then did so fully hit the mark that it was divided by it into two parts whose difference in weight was less than ten grains about the thirty third part of the whole Bullet although the lesser part was a little hollow and that from which the neck of Lead was a little too close pared off But when hindred from Recoiling only at R the Bullet mist the mark towards L or A for the whole Bullet less than two grains excepted went on that side And in like manner when hindred from Recoiling at L the Bullet mist the mark towards R or B the whole Bullet less than two grains excepted passing the knife on that side thereof I had the honour to make other Experiments with the same Engine lately at White-Hall before his Majesty and his Highness Royal within the Tilt-yard Gallery where there is the hearth of a Chimney raised a little above the floor about the distance of thirteen feet from the opposite wall against which I caused a Plank to be placed and the Engine to be laid first against the middle of the Hearth that it might not recoil at all and that part of the board to be marked against which 't was levelled known by a line stretched from the Breech of the Peece unto the Board directly over the sight and button and the fire being given the charge being but eight grains of Powder as before the Bullet did fully hit the mark Secondly the Peece charged and levelled in the same manner was laid at the end of the Hearth next the Park so that very little of the corner R rested against it and then the Bullet miss'd the mark about an inch and a quarter towards the Park or A. The like being done at the other end of the Hearth the Bullet then miss'd the mark as much the other way and afterwards with double that charge something more as before I had found it less with a smaller charge Since this at first designing only to experiment the several distances that the bullet is carried wide of the mark with different charges of Powder I made these Experiments following In the first Colume whereof you have the corner stopt from recoiling In the second the grains of Powder with which the Peece was charged In the third the distance the Bullet was shot wide from the mark in inches tenths and parts of tenths In the fourth the side on which the Bullet was carried In the last the distance of the mark from the muzzle of the Gun in feet B 16 0. N 9 L 48 0.5 L 9 R 39 0 3½ L 9 R 48 0.0 N 9 L 16 1 7½ R 9 L 56 0.8 L 9 R 39 0.2 L 9 R 48 0.1 L 9 R 16 1.5 L 9 L 96 1 2½ L 9 R 40 0.2 L 9 L 48 0 0¼ R 9 R 12 1.5 L 9 L 96 1.5 L 9 R 40 0.0 N 9 L 4 16 R 9 L 12 1 7½ R 9 L 40 0.5 L 9 R 40 0.2 L 9 L 4 1 5½ R 9 L 8 1.6 R 9 R 96 0.9 R 9 R 96 0 6½ R 9 R 4 1.6 L 9 R 8 1.1 L 9 B 8 0.2 R 9 L 96 1 0½ L 9 R 8 1.8 L 9 R 4 1.0 L 9 R 96 0.6 R 9 L 96 1 0½ L 9 L 8 1.8 R 9 L 4 1 1¼ R 9 L 96 0.9 L 9 R 96 0 7½ R 9 L 12 2.0 R 9 L 24 1 1½ R 9 L 40 0 1¼ L 9 R 96 1.0 R 9 R 12 2.1 L 9 L 32 0.6 R 9 L 38 0 1½ R 9 R 40 0.8 L 9 R 16 1 7½ L 9 L 40 0 1½ R 9 L 39 0 0½ L 9 L 40 0.5 R 9 L 16 1.8 R 9 L 48 0 4½ L 9 R 39 0.1 L 9 L 48 0.1 R 9 L 20 1.5 R 9 R 20 1 0½ L 9 R 12 0.6 L 2 R 48 0 0¼ L 2 L 20 0.2 R ¼ R 20 1.4 L 9 R 12 0 9¼ L 4 L 12 1.7 R 9 L 24 0.21 ◠R ¼ R 64¼ 0 7¼ R 9 R 12 1.2 L 6 L 12 0 2¼ R ¼ L 28 0.1 R ¼ L 64¼ 0 9¼ L 9 R 12 1 5½ L 8 L 12 0 6½ R 2 L 32 0 1½ R ¼ L 96 1.1 L 9 R 12 1.9 L 9 L 12 1.0 R 4 L 36 0 1¼ R ¼ R 96 0.7 R 9 B 12 0.1 L 9 L 12 1 1¼ R 6 L 40 0.1 R ¼ R 96 0.8 R 9 R 12 0.3 L ¼ L 48 0 0¼ R ¼ L 44 0 0½ R ¼ L 96 1.3 L 9 L 12 0 3½ R ¼ L 48 0 1½ L 2 L 48 0 0½ R ¼ L 96 1 3½ L 9 L 96 0 0½ R ¼ L 48 0 2½ L 4 L 52 0 0¼ R ¼ R 12 0 3½ L 6 R 96 0 0½ L ¼ L 48 0 5½ L 6 L 56 0 0¼ R ¼ R 12 1.3 L 9 R 96 0.2 R 2 L 4 0 1½ R ¼ L 60 0 0⅛ R ¼ L 12 0 6¼ R 2 L 96 0.2 L  L 4 0 1½ R ¼ L 64 0 0⅛ R ¼ L 12 1 0¼ R 4 L 48 0 1½ R ¼ L 8 0 3¼ R ¼ L 96 0.0 R ¼ L 12 1 2½ R 6 L 48 0.0 N 2 L 12 0.3 R ¼ L 96 1.1 L 9 L 12 1 4½ R 8 R 48 0 1¼ L ¼ L 16 0 2¼ R ¼      Whence you may be pleased to observe First That the recoil of the Peece being hindred only at R or L whatsoever be the charge of the Powder the Bullet still misses the mark placed at the mouth of the Gun on the same side that the recoil is made Secondly That about twelve grains of Powder shoots widest from the mark at all distances above mentioned on the same side that the Recoil is made Thirdly That above forty eight grains of Powder shoots wide from the mark placed at nine foot from the muzzle of the Peece on the contrary side to that on which the recoil is made The cause of the first I cannot doubt to be the recoil of the Peece from the force of the Powder before the Bullet be parted from it The second is as I conceive because with less than twelve grains the Peece