THE GUNNER'S GLASS

By WILLIAM ELDRED, sometimes Mr. Gunner of Dover Castle

1646

Wherein the diligent practitioner may see his defects, and may, from point to point, reform all errors that are commonly incident to unskillful gunners.

-- To The Reader --

The Master Gunner should give to the Captain or Commander of the Castle or Fort, once a month, an account of all the shots that have been made in that time - from which Mount; from what Piece; upon what occasion; what powder; the mark that they shot at; the allowance in degrees or inches and how it fell with the mark:

This will be a time for Mr. Gunner to express himself to the Commander. It will also stir up the Gunners to be carefull to perform their service considering that their doings will be examind once a month before the Governor or Commander. And encourage the industrious and admonish the slothfull.

Let every Gunner that hath the charge of ordnance upon any Mount or Platform, if it be not already named, to name it and set its number upon the knob of the Carnous at the breach with a hard chisel; then make you a note book, wherein after you have set down the numbers and names of your said peices, then take exactly the height of the bore which is called the Caliber, then the length of the peece, the height of the Base-Ring, the height of the muzzle-ring, and the thickness of the fortification (the metal in the chamber). Use this information with the Tables that will follow.

The Gunner must observe three things, firstly to know his Peece, and secondly her execution, and thirdly the distance to the mark. Without this it is impossible ever to make a good shot, except it be by chance, as the blind man hit the crow.

-- Chapter One --

Q. Which trades make better Gunners ?

A. Men that hath been trained up and exercised in labour & painstaking (carpenters, masons, brick-layers and strong, honest & discreet labourers). All lofty men that are industrious and diligent to learn, and may be competent in writing and reading. Schollars and Artificers are not excluded, but are not always to be found or spared.

What man more fit to remove a Peece and to bring her to the mark, than labourers, or such as used to lift and handle great burdens? Who more fit to perceive the faults and defects in the iron-work of a Peece than a smith? Who more fit to give directions for the mounting or dismounting of a Peece than a Carpenter?

Q. What of the duties and office of a Mr. Gunner ?

A. It is certain that this office is the most chief and eminent place in a Fort next to the Captain, and he is to see that all things belonging to the Ordnance be fit and in readiness; and first he ought to be a man of good discretion, and one that makes conscience to serve God, and also to be inbued with a competent knowledge of Mathematics, and to know the use of all Instruments for placing of Fortifications ands taking of distances, to have skill to set out platforms and placing the Ordances upon every place for the best and readiest service, to see the Ordnance be well fitted in their Carriages, to see that his Peeces be not defective; that they be even and truly bored, what flawes, cracks or honey-combs be in any of them, how they be fortified that they may bear their due charge without danger, that the carriage for the Ordnance be well and proportionably made to Caliber, Sponges and rammers for all his Peeces, to make his Quadrant sight rule and other instruments, taking of distances, and to teach the other Gunners the use of all such Instruments.

-- Chapter Two --

Q. Which manner of man he ought to be in qualities and conditions that will be a Gunner ?

A. He ought first and principally to be a man fearing God & by all means possible to walk faithfully before his sacred Majesty with an unpright heart, not given to much talking or many words, no quarreller or drunkard or idle gamester, but sober and of good conversation, and having pride of his own worth, inbewed with knowledge and skill in the profession of the Mathematicks.

Q. What of brass ordnance ?

A. It is said that if a brass peece explodes, the parts do not cause as much damage as an iron gun. This I have found not to be true and can cite many cases when brass fragments did kill men.

Of its weight, a brass saker will weigh 1600 - 1700 whilst an iron saker will weigh about 2500.

But brass weakens when it is hot, but iron ordnance is not hurt by heat. Brass is a compound of metals and iron is but one, and therefore is the stronger, for unity is more forcible than plurality.

Q. How shall I know one peece from another ?

A. All peeces are known by the height of the bore called the Caliber, but some refer to the Caliber as the height of the shot belonging to such a peece. Some reference is also made to the weight of the Ball.

Q. What of the parts of the Peece ?

A. The height of the bore is called the Caliber; the hollow of the said bore from the mouth to the breach is called the Cylinder, and of some authors the Soule but others the Chase, the nethermost part thereof next the touch-hole extending from the Touch-hole towards the mouth about some a foot or 18 inches, is called the Chamber, for in it lieth the powder, shot and wads and according to the thickness of the metal in the said chamber, is the allowance of powder to be given - as you shall see hereafter. The uppermost part of the metal at the breach of the Peece is called the Base-ring, the part of the Peece from that to the Button is called the Carnous; the ring of metal that compasses the Peece are called the Frise, the middlemost is called the Girdle, the uppermost Frise at the mouth is called the muzzle-ring. The two knobs projecting from the sides of the peece serving to hold the peece in her carriages are called the Tronions; and the metal of the Peece next the mouth is called the Neck of the Peece.

Note that the Tronions be well placed that the peece be not too heavy or too light in the breech; for if the peece be too heavy, the more help must be used to coyn her up to her mark, but if too light in the breech, then she will bob down her muzzle and lay her shot short.

Also observe whether your peece be upward or downward bored, or awry either to the right or the left hand, and that she be an even bored width, viz, not one place wide and another narrow.

-- Chapter Three --

Q. What course is to be used in the making of Cartridges ?

A. For your Cartriges that are to be made of Cloth, you must cut your cloth 4 Balls in length, and 3 in bredth, and leave a part for the seam in the breadth of half an inch, and likewise for the seam both below and above for the cover and bottom.

But for Paper Cartriges, from a Demi-Culverin downwards, you must have for every sort of Peece a Firmer turned for the same; whether it be Demi-Culverin, Saker or Minion, or otherwise, then upon these Firmers fitted to the several Peeces; you must take Royall-Paper and role it about the Firmer, and so then paste it together with paste or starch, and also the bottom to the same, and then take it off from the Firmer, and so let it dry till you have occasion to use them, and these are to be filled according to the direction of the Gunner, about four Balls in length, and this may suffice, both for Cloth and Paper Cartridges.

Q. How might I know and choose good Powder ?

A. There was in ancient time a kind of Powder called Serpentine Powder; why it was so called I need not here declare; this powder being the first, was made in a small kind of dust like meal, and was but of a weak receipt in comparison of that we now use, and neither was it corned as our powder that we use in these days, for which cause, though it were then but weak, and now the strength in a manner doubled; one pound of powder which is now in use is as strong as two pounds of the old serpentine powder.

But as concerning the choice of Powder, know that it is known by colour, taste and burning; if it be a blueish colour a little inclining to red, it is good; if you put down your hand into the barrel or take thereof in your hand, if it do not black much your hand, it is a good sign; Also if it have a sharp biting taste upon the tongue, it is a good sign; but if it be inclined to moisture and do give in the Barrel, and have a whitish matter, and somewhat blueish, it is a sign that the sulphur is not well fined.

But the chiefest way to know Powder is by the fining; test each barrel deliverd by firing a little measure on a plate; if it burns with a sudden flash, it is good, if it leaves little or no dross behind upon the board; but if it burn with lights or sparks rising up and fading down again, like a spark upon the board it is not good, nor well beaten or wrought; if there remains certain whitish grains, it is a sign of much salt in it; but if reddish remains or tawny, the fault is in the coles.

Q. Will a Peece that cannot reverse or recoil carry further than one which does ?

A. It is most certain the a Peece that doth not reverse will much out-shoot a Peece that doth reverse; as I have tryed often times; but in the year 1610 I was to shoot 3 demi-culverins, the peeces had 3 degrees by the Quadrant; and two of these peeces were upon wheels, the other lay in her carriage upon the ground, and could not reverse, but outshot the other two about 10 yards. I have proved this at diverse other times.

Q. What of the manner of loading your Ordnance ?

A. A Gunner should perform his postures orderly and comely and nimbly in the charging and discharging his Ordnance. Let the Gunner therefor endeavour to set forth himself with as comely a posture and grace, as he can possible, for the agility and comely carriage of a man in handling his ladle, sponge and loading his Peece is such an outward action as doth great content to the standers-by.

Let your right hand man bring your ladle and your sponge and place them on the right side of your peece between the wheel and the carriage and stand you on the same right side; then let him provide a fit shot for the peece and lay it ready; let your left hand man provide two wads of ocam, hay or straw and wind them as round and tight and place them between the spokes of the wheels that the wind blow them not away, and then let him fetch the budge-barrel with powder, then to lay your peece to pass to load, let your two assistants one on the right side, the other at the left, be ready with their levers - handspikes - to press up the peece to discharge the coyne and stand you with one leg within the carriage and the other without, but not both legs within the carriage, as that is unseemly; the coyne being discharged, draw back so that the peece may lie level or a little higher at the mouth than at the breach, then your peece being put back, which must first be done is ordered to load.

Then comely and gracefully take up your ladle and put it into the Peece, and turn and move it too and fro, to search if there be any stones or gravel in the same, that you may bring it out with your ladle, and so clear the Peece, and when you have well cleared the same from stones and gravel with your ladle, set by your ladle in his place, take your sponge in comely manner like a soldier, and sponge well your peece.

Then let your left man bring the budge-barrel, with the powder, and hold it up as high as his knee or waste, keeping the same, holding one hand under the leather to keep the powder that it scatter not least any be lost, then thrust in your ladle and fill the same at 2 or 3 proffers, your laddle thus filled, let your assistant with his hand strike off the loose powder.

Then with a steady hand put your ladle with the powder into the peece, keeping the thumb of your left hand close to the Peece, put in your Ladle with powder at three motions, and always carry a steady eye upon the ladle staff, as you put it in, that in no wise it may turn aside, till you feel the Ladle stop at the end of the chamber.

Then fix your thumb of your right hand on the upperside of the ladle staff, and empty your ladle clean, by turning your thumb that you fixed on the uppeside, with the ladle staff, till your thumb and staff that was uppermost before, is now undermost and so your ladle shall be clean emptyed, then withdraw your ladle a foot, and shake the same so that no loose powder may remain behind in the ladle, and the ladle thus emptied, bring it gently out, and take heed you shame not your self in bringing some powder out again with the ladle, which is imputed a great shame to a Gunner.

Your ladle thus emptied, turn your Rammer head gracefully, and put home your powder easily and gently and the powder thus put up, withdraw your rammer at three motions, the Rammer being out, if you load but with one Ladle, let your left hand man be ready with a good stiff wad, putting into the peece as far as he can reach with his arm, then let your right hand man hold his finger upon the vent, and so with your Rammer put home your first wad with a stroke or two, then as before, withdraw your rammer again at three motions, then when it is out, let your right hand mate put in the shot, being first regarded and well viewd lest it be not fit for the Peece, or too high or too low, or not round and not knotty or craggy, for such a shot too high may clog the peece and not go home to the wad and so danger the breaking of the Peece also a shot too low will never go right to the mark, but will be either wide or short, but by reason of the play that it hath in the peece may prove stark naught, and note that a quarter of an inch vent is always fit to be allowed in a Peece, be it great or small, your shot being put in, it may be will roll down, but do not trust to that, but feel it gently home with your Rammer head, and beware of any swift motion, lest you strike fire and so mar all.

Your shot being home, let your left hand mate put in your last wad, as before which you may boldly and strongly put up, and when you feel it home, give it 3 good strokes with the Rammer head, then Gage your peece to see if it all be well, then run up your peece and lay her water-borne, and thus in as brief a manner as I can, I have shewed you the order of loading or the charging of a Peece of Ordnance.

This large discourse is here collected into some memorable words of direction in loading, which may serve instead of postures.

1. Put back your peece.
2. Order your peece to load.
3. Search your peece.
4. Sponge your peece.
5. Fill your ladle.
6. Put in your powder.
7. Empty your ladle.
8. Put up your powder.
9. Thrust home your wad.
10. Regard your shot.
11. Put home your shot gently.
12. Thrust home your last wad with three strokes.
13. Gage your peece.

Q. What do you mean by 'dispart' ?

A. The shot is delivered in a straight line from the cylinder to the mouth of the peece and so to the mark. Terefore the mouth must be brought equal to the cylinder, and this may be done by cutting a little stick or straw of the length difference between the height of the mouth and the mettal, and the cylinder and its mettal; and fasten it upon the muzzle-ring with wax or clay - and this is called the Dispart.

Among the diverse instrumenst used by Gunners, there is a pair of Compasses called Callipoers, which be compasses with crooked points, which are or ought to be a foot or 16 inches long, with which you must take the height of the metal at the breach, and the height of the metal at the mouth of any peece, and half the difference of these two is the true dispart of a peece.

Q. What instruments do belong to a Gunner ?

A. First a Quadrant; secondly a sight-rule; thirdly a pair of compasses with crooked points called calipers; fourthly a pair of straight pointed compasses; fifthly a height board to try and pass your shot through; sixthly a case of primimg irons of all sorts; seventhly, a horn or two for priming powder; eighthly a steel to strike fire; ninethly, two or three linstocks to give fire well armed with match - these things no Gunners can well be without.

Q. What of the range of all peeces ?

A. Add to your list of peeces the ranges of each Ordnance with allowance in degrees. I will also give you a note of general supposition:

• A Falcon will carry level 16 score, and upon the mount of a degree, 8 score.
• A Saker will carry level 18 score, and upon a degree 9 score.
• A Demi-Culverin 20 score, and upon a degree 10 score.
• A Whole-Culverin 22 score, and upon a degree 11 score.
• A Demi-Cannon 19 score, and upon a degree 9 1/2 score.
• A Whole-Cannon 17 score, and upon a degree 8 1/2 score

Also a table of some of the Peeces on a mount at Dover Castle.

Where, 1 score = 20 yards. 1 mile = 1,760 yards = 88 score.

Q. Show me the course and way of the Quadrant; let me therefore know the manner of shooting by it, in as plain and brief an order as you can ?

A. The ground of all shooting is by the Quadrant; but it is troublesome and unfit to be used in time of service or in haste; the sight-rule was invented being the readiest way to make a shot in haste, but this way by the sight-rule was derived from the Quadrant. The manner of shooting by the Quadrant, you must first consider whether your Peece be higher than your mark, or your mark higher than your Peece, that is how many degrees of the Quadrant the one is higher than the other, or whether your Peece and your mark be level, and this you may know by your Quadrant thus.

Dispart your Peece very exactly, and lay your Peece so disparted, I mean the dispart set or fastened, with wax or clay upon the Peece; then lay the top of the dispart to the mark, and put your Quadrant into the mouth of the Peece, and you shall see by the thread whether it be level or above level by so many degrees as the thread sheweth, and so lay your peece accordingly.

Q. I entreat you give me some plain rules of direction to take a distance to a mark without the which knowledge a Gunner may well be said to be lame, and reputed a blind Gunner, because he knoweth not what he doth, and I would be loath to be accounted such a man.

A. It is not every mans case to know or to have the skill to use such Mathematical instruments as are requisite for such a business, such as are the plain Table, the Theodolite, the Circumferenter, the Cross-staff, and many other instruments, every one of which will require a long discourse, and require great pains to attain the knowledge of the same, all which Instruments I have used at leisure times; but because these do more belong to the Engineer than the Gunner, I will let them pass, and will set down such main directions as may be performed by the Gunners Quadrant and Sight-rule and a pair of Compasses; but I would not have you or any man to think that this is performed so precisely, but some difference may fall out of a 4 or 5 yards or more, in a long distance, and moreover, this I say, if you take your distance never so true, yet you shall never order your Peece so in a long distance to shoot in at the same hole; but you may be very neer and may serve your turn to help you to make a fair shot to a mark, which you cannot else do, except you know, or at least give a near estimate of the distance.

If your Mount or Plat-form be upon a hill or a Tower, or Cliff or Rock towards sea or land; take your peece and traverse her to the mark or place of which you desire to know the distance, and dispart exactly, your Peece laying just right with the same then lay her perfectly level by means of help of your Quadrant, then take your Sight-rule and set it upon the Base-Ring, as though you would give level to a mark, then raise up your sight upon your rule till you see the bottom of the mark even by the top of the dispart, then see how many times that height of the sight is contained in the length of the peece from the Base-Ring to the dispart, and so much is the height you stand upon contained in the distance to the mark.

Suppose I stand upon a Platform that I know to be 20 yards high, that is a score; I take one of my Peeces and turn her to a ship at sea which I am to shoot at, and being disparted, I lay her level towards the ship, and I take my rule and raise the sight til I can see the bottom of the ship by the top of the dispart, then I take that height of the sight with a pair of compasses, and that wideness remaining, I try how many times that wideness is contained in the length of the Peece between the Base-ring and the dispart, and I find it 48 times and a half; therefore I say the ship or mark is 48 score and a half distant.

I will now give you another rule with a Table of Tangents and Secants, whereby you may also perform this rule of taking a Distance more exactly.

First you must understand the Triangle which is called a Scalenum, containing one right Angle and two inequal sides.

Now this perpendicular making a right Angle in A is always to signify the height whereupon we stand; the Basis being the Tangent line always sheweth the distance. How often this Radius or height is contained in that line, which by the degree of the Quadrant where the sight to the mark cutteth the said Tangent, which line is called the Secant, where the Tangent and Secant cross one another, there is the distance, and showeth how often the Radius or height is contained in the Base-line.

The Table given hereafter will show you how often the Radius, AB, is contained in any distance, the Tangent line, BC.

Suppose I stand upon a Tower that is 20 yards high, and I see a ship or mark which I aim to shoot at, and I take my Quadrant and by the sights I see the ship, and my plummet cuts 5 degrees 10 minutes under level. I look in the Table for 5 degrees in the head and for 10 minutes at the left side, and there I see 11 4/5 which showeth me that the Radius or height is contained 11 4/5 at the Radius, which is 11 score and three quarters of a yard.

Taking distance with a compass.

Describe now the Triangle called Isoceles, which hath only two equal sides, being represented by the letters AB and AC, then seeing these two AB and AC are equal, their sections AD and AE must needs be equal, and shall be cut proportionally, and if we draw the lines BC and DE they will be parallel by the second proposition of the 6 book of Eucled, and so the Triangle ABC and ADE shall be equi-angle by reason of the common Angle of A and the equal Angles of the Base, and therefore shall have the sides also proportional, about those Angles by the fourth proposition of the sixth book of Euclid, and so the side AD shall be the side AB as the Basis DE is unto the Parallel Basis BC and by conversion, AB shall be unto DE as AB to BC et cetera. So that if AD be the fourth part of the side AB then DE shall also be the fourth part of his Parallel Basis BC the like reason holdeth in all other Sections.

Here you see that as often as DE is contained in AD or AE, so often is BC contained in AB or AC for as the line DE is contained 3 times in AD or AC, so is the line BC contained 3 times AC or AB, and upon this ground I hold my proposition, that if I take a pair of Compasses in my right hand, and standing upright with my body, and opening my compasses to the length of any known line or mark, stretching out my arms straight then look how often the opening of my compasses is contained from the points of the same to my eye, so often is the length of the known line or mark contained in the distance to my standing, and therefore mark this well.

I will assay to prove it by example. Suppose I am to take a shot at a ship at sea, whose distance I desire to know, and I know the Barque to be 20 yards long, from the stern to the brake head, I take my compasses in my right hand, and then stretching out mine arms to full length, I find the length of mine Arm from my Eye to the points of my Compass ro be 30 inches which I always keep and do mark upon my staff or walking stick, which I always continue with me; now I stretch out my Arm with my compasses, and open or shut the same to the just length of the ship or Barque, and that wideness remaining, I see upon my walking stick how often it is contained from the end of my stick to the mark, which I made, being the distance from my eye to the points of my compasses, and I find it 58 times, then I say, the mark or ship being 20 yards which is a score, then I say the ship is 58 score off; and I must give a Demi-Culverin almost 4 degrees to reach the mark.

The Gunner is to mark him a Table with the Randons of all his several peeces of ordnance under his charge. An example follows: