Chapter XIII: Preface (13)

The easiest Method of perpetuating the Use of the many coulter’d Ploughs, and other newly-invented Instruments of Husbandry, is by Models, _i. e._ the Things themselves in little; and these may be all portable even in a Man’s Pocket: Every Part must be fully described, with the true Dimensions, and the mathematical Reasons, on which their Contrivance is founded. Directions also for using them must be given at the same time that their Manner of making is described. In some, the very Horses which draw must be represented, to shew the manner of fixing the Horses, and the Traces: Cautions against all the Errors that may happen by the want of Experience in the Makers or Users, must be given.

When this is done, and the Rules put into a Method, the new Hoeing-Husbandry, in all its Branches, will be much more easy and certain than the old; because there are no mathematical Rules extant in any Method; and a Man may practise the old random Husbandry all his Life, without attaining so much Certainty in Agriculture as may be learned in a few Hours from such a Treatise.

The Rules, indeed, require much Labour, Study, and Experience, to compose them; but when finish’d, will be most easy to practise: Like the Rules for measuring Timber; their Use is, at first Sight, easy to every Carpenter, and to most Artificers who work in Wood; but no illiterate Person is able to compose those Rules, or to measure Timber without them.

CHAP. XIX.

_The Description of a_ Four-coulter’d Plough.

To describe all Parts of a Plough geometrically, would require more Time and Learning than I am Master of: Therefore leaving that to be done by somebody else, who is better qualified for it, I shall at present attempt little more than what relates to the Three added Coulters.

In _Plate_ I. _Fig._ I. is the Portrait of a common Two-wheel’d Plough used in _Berkshire_, _Hampshire_, _Oxfordshire_, and _Wiltshire_, and in most other Countries of _South-Britain_; and is generally esteemed the best Plough for all Sorts of Land, except such miry Clays that stick to the Wheels, and clog them up, so as they cannot turn round.

But they have, in some Places, a Contrivance to prevent this Inconvenience; which is done by winding Thumb-ropes of Straw about the Iron Circles of the Wheels, and about the Spokes. The Wheels pressing against the Ground, the Thumb-ropes are distended on each Side: which Motion throws off the Dirt, and prevents its sticking to the Wheels, which it would otherwise do.

’Tis commonly divided into Two Parts; _viz._ the Plough-head, and the Plough-tail.

The Plough-head contains the Two Wheels A, B, and their Axis or Spindle of Iron passing thro’ the Box C, turning round both therein, and in the Wheels; the Two Crow-staves D, D, fastened into the Box perpendicularly, and having in each Two Rows of Holes, whereby to raise or sink the Beam, by pinning up or down, the Pillow E, to increase or diminish the Depth of the Furrow; the Gallows F, thro’ which the Crow-staves pass at top, by Mortises, into which they are pinned; G the Wilds with its Links and Crooks of Iron, whereby the whole Plough is drawn; H the Two-chain, which fastens the Plough-tail to the Plough-head, by the Collar I at one End, and by the other End passing thro’ a Hole in the Middle of the Box, is pinned in by the Stake K; L the Bridle-chain, one End whereof is fastened to the Beam by a Pin, and the other End to the Top of the Stake, which Stake is held up to the left Crow-staff, by the With M, patting round it above, and under the End of the Gallows below; or instead of this With, by a Piece of Cord, and sometimes by the End of the Bridle-chain, when that is long enough.

The Plough-tail consists of the Beam N: the Coulter O; the Share P; and the Sheat Q; the Hinder-sheat R, passing thro’ the Beam near its End; S the short Handle, fastened to the Top of the Hinder-sheat by a Pin, and to the Top of the Sheat by another Pin; T the Drock which belongs to the right Side of the Plough-tail, and whereto the Ground-wrist V is fasten’d; as is the Earth-board, whose Fore-part W is seen before the Sheat; and also the long Handle X, whose Fore-part Y appears before the Sheat, and is fasten’d to the Drock by a Pin at _a_, the other End of which Pin goes into the Beam. Z is the double Retch, which holds up the Sheat, and passes through the Beam to be fasten’d by its Screws and Nuts at _b_ and _c_.

But without intrenching much farther upon the common Plough-wright’s Art, whose Trade is his Living, I’ll hasten to shew the necessary Difference there is betwixt the common Plough, and the Four-coulter Plough, beginning with _Fig._ 2. where it is represented as standing upon a level Surface.

_Fig._ 2. And, First, The Beam differs in Length, being Ten Feet Four Inches long, as the other Plough-beam is but Eight Feet; it differs in Shape, as the other is strait from one End to the other, but this is strait only from _a_ to _b_, and thence turns up of a sudden, in the manner that is shewn in the Cut; so that a Line let down perpendicular, from the Corner at _a_, to the even Surface whereon the Plough stands, would be Eleven Inches and an half, which is its Height in that Place; and, if another Line were let down, from the turning of the Beam at _b_, to the same Surface, it would be One Foot Eight Inches and an half, which is the Height that the Beam stands from the Ground, at that Part; and a Third Line let down to the Surface, from the Bottom of the Beam, at that Part which bears upon the Pillow, will shew the Beam to be Two Feet Ten Inches high above the Surface in that Part.

From the End _a_, to the Back-part of the first Coulter, is Three Feet Two Inches; from thence, to the Back of the next Coulter, is Thirteen Inches; thence to the Third, Thirteen Inches; and from thence to the Fourth, the same. From _a_ to _b_ is Seven Feet.

This Crookedness of the Beam is to avoid the too great Length of the foremost Coulters, which would be necessary if the Beam was strait; and then, unless they were vastly thick and heavy, they would be apt to bend, and the Point of the Fourth would be at so great a Distance from its Coulter-hole, that it would have the greater Power to loosen the Wedges, whereby the Coulter would rise up out of its Work, as it never doth when the Beam is made in this bending Manner. This Beam is made either of Ash, which is the lightest, or of Oak, which is the most durable. Its Depth and Breadth may vary, according to the heavier or lighter Soil it is to till; but this before us is in Depth Five Inches at the first Coulter-hole, and in Breadth Four Inches.

_Fig._ 4. Is the Sheat Q in _Fig._ 1. (broad Seven Inches) with the Iron Retch on it, the left Leg of which Retch must stand foremost, to the end that the Edge of its Fore-part, that is flat, may fit close to the Wood of the Sheat: This Retch holds the Sheat fast up to the Beam by its Nuts and Screws; as also doth a Pin driven into the Hole _a_, which Hole being a small Part of it within the Beam, the Pin being driven into the Hole, draws up the Sheat very tight to the Beam. The principal thing to be taken notice of here, is the Angle _b c d_, which shews the Elevation of the Sheat; the Line _c d_ is supposed to be equal with the Bottom of the Share (or rather with the plain Surface whereon it stands); when this Angle at _c_ is larger than of Forty-five Degrees, a common Plough never goes well: In my Four-coulter Plough I choose to have it of Forty-two or Forty-three at the most.

_Fig._ 5. Is the Share; _a_ is the End of the Point; _b_ is the Tail of the Share, long from _a_ to _b_ Three Feet Nine Inches; _c_ the Fin; _d_ the Socket, into which the Bottom of the Sheat enters; _e_ a thin Plate of Iron riveted to the Tail of the Share: By this Plate, the Tail of the Share is held to the hinder Sheat, as at _d_ in _Fig._ 1. by a small Iron Pin with a Screw at its End, and a Nut screw’d on it on the inner or right Side of that Sheat. From _a_ to _f_ is the Point, long about Three Inches and an half, flat underneath, and round at Top: It should be of hard Steel underneath. From _f_ to _c_ is the Edge of the Fin, which should be well steeled; the Length of it is uncertain, but it should never make a less Angle at _f_ than it appears to make in this _Fig._ The Socket is a Mortise of about a Foot long, at the upper Part, Two Inches deep: The Fore-end of this Mortise must not be perpendicular, but oblique, conformable to the Fore-part of the Sheat which enters it; the upper Edge of which Fore-part must always bear against the Sheat at _e_ in _Fig._ 4. but if this End of the Socket should not be quite so oblique as the Sheat, it may be help’d, by taking off a little of the Wood at the Point _c_.

_Fig._ 6. Shews the Share, with its right Side upwards, in the same Posture as when it plows; whose Side _a b_ should be perfectly strait, but its under Side at _c_, which is its Neck, should be a little hollow from the Ground, but never more than half an Inch in any Plough, and a Quarter of an Inch in a Four-coulter Plough; so that the Share, when it is first made, standing upon its Bottom, bears upon the level Surface only in Three Places; _viz._ at the very Point _a_, at the Tail _b_, and at the Corner of the Fin _d_.

_Fig._ 7. Is the Share, turn’d Bottom upwards; and shews the Concavity of the Fin at _a_; which must be greatest in a stony rubbly Soil.

_Fig._ 8. Shews the Share, the right Side upwards, but leaning towards the Left.

In placing of the Share rightly upon the Sheat, consists the well going of a Plough, and is the most difficult Part of a Plough-wright’s Trade, and is very difficult to be shewn. Supposing the Axis of the strait Beam, and the left Side of the Share, to be both horizontal, they must never be parallel to each other; for if they were, the Tail of the Share, bearing against the Side of the Trench, as much as the Point, would cause the Point to incline to the right Hand, and go out of the Ground into the Furrow. If the Point of the Share should be set, so that its Side should make an Angle on the right Side of the Axis of the Beam, this Inconvenience would be much greater; and if its Point should incline much to the Left, and make too large an Angle on that Side with the Axis of the Beam, the Plough would run quite to the left Hand; and if the Holder, to prevent its running out of the Ground, turns the upper Part of his Plough towards the left Hand, the Fin of the Share will rise up, and cut the Furrow diagonally[259], leaving it half unplow’d; beside, the Plough will rise up at the Tail, and go all upon the Point of the Share: To avoid these Inconveniences, the strait Side of the Share must make an Angle on the left Side of the Beam, but so very acute, that the Tail of the Share may only press less against the Side of the Trench than the Point does. This Angle is shewn by the prick’d Lines at the Bottom of _Fig._ 1. where the prick’d Line _e f_ is supposed to be the Axis of the Beam let down to the Surface, and the prick’d Line _g f_ parallel to the left Side of the Share; but this Angle will vary as those Two prick’d Lines are produc’d forwards to the Fore-end of a long and a short Beam, keeping the same Subtense: For Plough-wrights always take this Subtense at the Fore-end of a Beam, whether it be a long Beam or short one; and it is the Subtense _e g_, that determines the Inclination the Point of the Share must have toward the left Hand. Plough-wrights differ much in this Matter; but, by what I can learn by those that make the Ploughs I see perform the best, this Subtense at the Fore-end of an Eight-feet Beam should never be more than one Inch and an half; and by full Experience I find, that whether the Beam be long or short, the Subtense must be the same; for when my Plough-wrights take this Subtense at Eight Feet from the Tail, when they make my Four-coulter Plough, whose Beam is Ten Feet Four Inches long, the Point of the Share will incline too much to the Left, and it will not go well until this Fault be mended, by taking the same Subtense quite at the End of the Beam; which makes the mentioned Angle more acute.

[259] This is the greatest Misfortune incident to a common
Two-wheeled Plough, and happens generally by the Fault of the Maker,
though sometimes by the Plowman’s setting it so, that the Point of
the Share turns too much to the Left. I have seen Land plowed in this
manner, where not half of it has been moved, nor better tilled than
by Raftering, not only cut diagonally, but also half the Surface
hath remained whole, where when the Earth that was thrown on it was
removed, the Weeds appeared unhurt on the unplowed Surface. In this
Case, they for a Remedy let the Plough to go deeper; and then, if it
go deep enough for the Fin to cut off the Furrow at a just Depth, the
Point will go below the Staple, which may ruin the Soil, unless it be
very deep.

When our _English_ Ploughs go in this manner, they make much worse
Work than the _Eastern_ Ploughs, that have no Coulter; for these,
contrary to ours, though they always cut their Furrow diagonally,
cut it thin on that Side from which it is turned, as our bad Ploughs
leave it thin on that Side towards which it is turned. The Earth the
_Easterns_ leave by their Diagonal in one Furrow, is taken off by
the next; but ours leaving Part of their Furrow behind them, on the
Side next to the plowed Part of the Field, come at it no more; but
the other can plow cleaner, their Diagonal being contrary to ours,
which leaves the Trench deepest on the Side next to the unplowed Part
of the Field; but unless the Fin of the Four-coultered Plough go
parallel to the Surface of the Earth, it will not plough at all; or
will leave Two or Three of its Four Furrows untouched.

_Fig._ 3. Shews the right-hand Side, and upper Side of the Four-coulter Plough, of which V the Iron Ground-wrist is shewn in _Fig._ 9. long Two Feet Five Inches, deep at the End _b_ Four Inches, and Three-eighths of an Inch thick, except at the End _a_, where it is thin enough to bend, so as to fit close to the Share, as at _e_, in _Fig._ 6. The Ground-wrist has Four small Holes near its End _a_, into one of which goes a Nail, to fasten it to the Shear, thro’ the long Hole in the Side of the Socket of the Share, as at _a_, in _Fig._ 10. and then it will stand in the Posture shewn by _e f_, in _Fig._ 6. From the Outside of the Ground-wrist at _f_, to the Outside of the Share at _b_, is Eleven Inches and an half, which is the Width of the lower Part of the Plough-tail at the Ground; the Ground-wrist has several Holes at the upper Side of its broadest End, as at _b_, in _Fig._ 9. by which it is nailed to the lower Part of the Drock T, as in _Fig._ 3. which Drock with its Perforations is shewn in _Fig._ 11.

_Fig._ 12. Is the Earth-board, with its Inside upwards; the Notch _a b_ shews the Rising of the Wood, which takes hold of the Edge of the Sheat, to hold it the firmer, to which it is fastened by the Holes _c_ and _d_; and at the other End it is fastened to the Drock, at the Hole _e_. All which is seen as it stands mark’d with W, in _Fig._ 3. But this Pin, with which it is fastened to the Drock, is bigger in the Middle than at each End; which prevents the Earth-board from coming near the Drock: By this Pin, the Earth-board is set at a greater or less Distance from the Drock, as there is Occasion to throw off the Furrow farther from the Plough at some times than at others: It always stands considerably farther out on the right Hand than the Ground-wrist does, which is one Reason that the Drock is made crooked, bending outwards in that Part.

The long Handle X is _Fig._ 13. long Five Feet Four Inches, broad in the widest Part Four Inches, pinned to the Sheat thro’ the Holes _a b_, and pinned to the Drock through the Hole _c_.

The short Handle S is _Fig._ 14. and is long Three Feet Nine Inches, pinned to the hinder Sheat (being _Fig._ 15.) by the Hole _a_, and to the Top of the Fore-sheat above the Beam by the Hole _b_.

The Handles are made so long, for the more easy guiding of the Plough; but the lazy Ploughman is apt to cut them off shorter, close up to the Plough, to the end that, bearing his whole Weight thereon, he may in a manner ride instead of walking; but if he should thus ride on long Handles, he would tilt up the Fore-end of the Beam, and raise the Share out of the Ground.

The chief, and most indispensably necessary thing to be observed, is, to place the Four Coulters in such a manner, that the Four imaginary Planes described by the Edges of the Four Coulters, as the Plough moves forwards, be all of them parallel to each other, or very nearly so; for if any one of them should be much inclined to, or recede from, either of the other three, they could not enter the Ground together. In order to place them thus, the Coulter-holes must be made through the Beam, in the manner as they are shewn in _Fig._ 3. _viz._ the Second Coulter-hole is Two Inches and an half more on the Right than the First, the Third, Two and an half more on the right Hand than the Second, and the Fourth, Two Inches and an half more on the right Hand than the Third, conformable to the Four Incisions or Cuts they are to make in a Ten-inch Furrow: And because no single Beam is broad enough to hold the Four Coulter-holes at this Distance, we are forced to add the Piece shewn in _Fig._ 16. The Second Hole is made Part in the Beam, and Part in this Piece; the Third and Fourth are made wholly in this Piece, in which _a_, _b_, _c_, are the Ends of the Three Screws, which fasten the Piece to the right Side of the Beam by their Nuts.

The Distance of Two Inches and an half, by which each of the Three added Coulters stand more to the right Hand than that immediately behind it, must be reckoned from the Middle of one Hole to the Middle of the other.

The Fore-part of every Hole must incline a little towards the Left; so that the Backs of the Coulters may not bear against the left Side of the Incisions made by the Edges.

Each Hole, being a Mortise, is one Inch and a quarter wide, with its Two opposite Sides parallel from Top to Bottom; each of these Mortises, or Holes, are long at Top Three Inches and an half, and at Bottom Three Inches; the Back-part, or Hinder-end, of each Coulter-hole is not perpendicular, but oblique, and determines the Obliquity of the Standing of the Coulter, which is wedged tight up to it by the Poll-wedge _i_, _Fig._ 1. as all Coulters are.

_Fig._ 17. Is a Coulter; _a b_ is its Length, being Two Feet Eight Inches, before it is worn; _e d_ is its Edge, Sixteen Inches long; _d c_ is the Length of its Handle, Sixteen Inches; this is made thus long, at first, to stand above the Plough, that it may be driven down lower, according as the Point wears shorter; this Handle is One Inch and Seven Eighths broad, and Seven Eighths of an Inch thick, equally thro’ its whole Length: Its Breadth and Thickness might be described by a rectangled Parallelogram.

In all Ploughs this first Coulter is, or ought to be, placed in the Beam in manner following; _viz._ its Back to bear against the Back of the Coulter-hole, its right Side above to bear against the upper Edge of the Coulter-hole, and its left Side to bear against the lower Edge of the Coulter-hole; so that always Three Wedges at least will be necessary to hold the Coulter; the Poll-wedge before it, as at _i_, in _Fig._ 1. another Wedge on the left Side of it above, and a Third on the right Side underneath: The Coulter-hole must be so made, that the Coulter standing thus across the Hole, its Point may incline so much towards the Left, as to be about Two Inches and an half farther to the Left[260] than the Point of the Share, if it were driven down as low as it; but it never ought to be so low in any Plough: As to its bearing forwards, the Point of the Coulter should never be before the Middle of the Point of the Share: What Angle the Coulter would make with the Bottom of the Share, may be seen by the Posture it stands in, in _Fig._ 1. If it should be set much more obliquely, it would have a greater Force to raise up the Poll-wedge, and get loose.

[260] I find that sometimes it is necessary in some of these Ploughs
for the Point of this Coulter to stand yet farther on the Left of the
Share’s Point.

The Three added Coulters should stand in the same Posture with this already described, in regard to the Inclination of their Points towards the Left: And this is a very great Advantage to them; for by this means, when the Fin is rais’d up, by turning the Handles towards the Left, their Points do not rise out of the Ground on the right Hand, as they would do without this described Inclination towards the Left; but in regard to their Pointing forwards, I find it best, that every one of the Three should be a little more perpendicular than that next behind it. So the Coulter 4 stands the nearest to Perpendicular of any of them. By this means there being more Room betwixt them above than below, they are the more easily freed from the Turf, whenever the Pieces, being covered with a great Quantity of Couch-grass, or the like, rise up betwixt them: which tho’ this seldom happens, makes a Necessity for a Man, or a Boy, to go on the Side with a forked Stick, to push out the Turf and Grass, which might otherwise fill the Spaces betwixt the Coulters, and raise up the Plough out of its Work.

’Tis to be observed, that none of these Coulters ought to descend so low as the Bottom of the Share, except when you plow very shallow: ’Tis always sufficient that they cut through the Turf, let the Plough go never so deep in the Ground.

It is necessary also, that when you plow very shallow, the Fin of the Share be broad enough to cut off the Fourth Piece or Furrow; else that, lying fast, will be apt to raise up the Ground-wrist, and throw out the Plough: But when you plow deep, the Ground-wrist will break off this Fourth Furrow, altho’ the Fin be not broad enough to reach it.

Sometimes the First or left Furrow is apt to come through betwixt the First Coulter and the Sheat, and so falls on the left-hand Side of the Plough: This is no Injury; but yet it is prevented, by letting the Second Coulter stand a little higher than the Third; and then the Second Furrow, holding the First at its Bottom, will carry it over, together with itself, on the right Side by the Earth-board; but yet never set this, or any of the Three added Coulters, so high that they may not cut through the Turf. But as for the first Coulter, tho’ it should cut but an Inch or Two within the Ground, the Share will break off the first Furrow in raising it up.

Remember, as often as the Point of any Coulter is worn too short, that you drive down the Coulter with a large Hammer, carried for that Purpose; and when it is driven low enough, fasten the Wedges again, so as to keep the Coulters in their right Postures, that their Incisions may be all of them equidistant.

_Fig._ 18. Is a Nut, with Two of its opposite Corners turn’d up, by which it is driven round by a Hammer, and has so great a Force, that Three of them, with their Screws properly placed, hold the Piece, _Fig._ 16. as fast to the Plough-beam, as if they both were made of one Piece of Wood; but as often as the Wood shrinks in dry Weather, the Nuts must be screw’d farther on, both here and in all other Places where they are used: particularly, those which hold up the Retch; for if the Sheat should once get loose, there is no Cure but by a new one.

Betwixt this Nut and the Wood, there should be a thin Iron Bolster, about the Thickness of a Shilling, broader than the Nut, to prevent the Nut from eating into the Wood, especially when it is to be often screw’d, as on the Retch of these Ploughs, and most of all on the Hoe-plough; but sometimes we use a Piece of Shoe-leather instead of an Iron Bolster.

_Note_, There must be Iron Plates upon all the Coulter-holes both above and below, Three of which are seen on the Piece in _Fig._ 16. There is no need to say how they must be nailed on with many Nails made for the Purpose.

_Fig._ 19. Is the Iron Collar, fastened to the Beam by Two short Crooks A, B, which take hold of Two short Pins driven into the Plough just behind the Second Coulter-hole, one on one Side, and the other on the other Side of the Beam. The Crook A is seen on the left Side of the Beam near _c_, in _Fig._ 2. the Crook B doing the same on the other Side of the Beam, which is seen near _a_, in _Fig._ 3. C is the Crook (for its Shape called a C) which holds the Tow-chain to the Collar by the Link D, being Part of the said Chain taking hold of its Fore-claw; the other Claw taking hold of one of the Five Notches of the Collar: This Collar is partly seen at _d_, in _Fig._ 2. Both the Claws of the Crook (or C) turn upwards, so that they cannot take hold of any thing that may rise under the Plough: The Use of the Notches is to help the Direction of the Point of the Share, which has been described by the prick’d Lines under _Fig._ 1. As the Point of the Share wears, it inclines a little more towards the Right, and is remedied by moving the Crook into a Notch nearer to the Left, which will direct the Point a little more towards the Left: This is more easy to be done here than in the common Plough, whose Collar moves round the Beam: We can, by changing the Crook from one Notch to another, incline the Point of the Share towards the Right or Left at Pleasure. The Length of each Side of this Collar is a Foot long.

The Tow-chain is best seen in _Fig._ 3. where the Link Y is that which passes thro’ the Box, and is pinned in by the Stake, as has been shewn in _Fig._ 1. which Stake is commonly nailed to the Box, to prevent its rising up. When we would draw up the Plough a little nearer to the Crow-staves, we take hold of the Crook by a Second or Third Link. _Note_, That the shortening of the Chain does also a little incline the Point of the Share towards the Left.

_Fig._ 20. is the Iron-wilds. The Leg A is of one Piece with that which has the Notch, and that passes thro’ the Leg B by the Loop at _a_; both which Legs pass thro’ the Box, and are pinned in behind it, by the crooked Pins C, D. This Figure is seen with its Crooks on it, both in _Fig._ 1. and _Fig._ 2. _Note_, That the Holes in the Box, thro’ which these Legs pass, must not be made at right Angles with the Box, but must incline upwards, so that the Fore-part of the Wilds may be higher than the Hinder-part, or else the Upper-part of the Crow-staves would lean quite back when the Plough is drawn. If the Beasts that draw immediately next to the Plough be very high, their Traces must be the longer; else they and the Wilds making too small an Angle with the Tow-chain at the Box, when they draw hard, the Wheels will rise from the Ground, and be apt to overturn: This Angle I suppose should not be less than of 160 Degrees, and the Angle made by the Tow-chain or Traces that are drawn by the Cattle that go before them, will make an Angle with the Tow-chain at the Box yet much more obtuse. The Use of these Notches in the Wilds is, to give the Plough a broader or narrower Furrow: If the Links are moved to the Notches on the right Hand, it brings the Wheels towards the left Hand, which gives a greater Furrow; and when the Links are moved towards the left Hand, it gives a less Furrow, by bringing the Wheels towards the right Hand.

The Distance betwixt the Two Legs of the Wilds is Eight Inches and an half; the Length of the Legs is Nineteen Inches. They must be of convenient Strength. The Links being placed in Notches distant from one another, prevents one Wheel from advanceing before the other; which would happen, if the Links were both in One Notch, or in Two adjoining Notches, except they were middle Notches: These Links are each Six Inches and an half long.

E is the Ring, by which the Two Links, and the Two Crooks F and G, are held together, and on which they all move.

The Height of the Wheels in _Fig._ 2. The left-hand Wheel is Twenty Inches Diameter; the Diameter of the right Wheel is Two Feet Three Inches; the Distance the Wheels are set from each other at the Ground, is Two Feet Five Inches and an half; the Crow-staves are One Foot Eleven Inches high, from the Box to the Gallows; they both stand perpendicular to the Box, and the Distance between the Crow-staves is Ten Inches and an half. The Pillow is pinned up at its Ends by Two small Iron Pins, which are chained to it, that if they drop, they may not be lost. These appear in _Fig._ 1. and _Fig._ 2. The Height from the level Surface, up to the Hole in the Box, where the Tow-chain passes through it, is Thirteen Inches (being Two Inches below the Holes of the Wilds, on the Hinder-side of the Box); the Height at the other End, where the Crook of the Collar takes hold of the Pin in the Beam at _c_, in _Fig._ 2. is Twenty Inches high above the same level Surface, and shews how much the Chain descends forward, for drawing down the Plough, and by which Descent may be known what Angle the Chain would make with the Surface, if it were produced forwards in a strait Line; which is a thing material for the good going of a Plough; and so is the Angle the Tow-chain makes with the Beam: About the Middle of this Tow-chain, there should be a Swivel, whereby one End of the Chain may turn without the other.

When this Four coulter Plough is made, I would advise, that it be tried with only the first Coulter, before the other Three are put in; for if the Plough does not go well with One Coulter, it is not likely it should go well with Four; and I never yet have seen or heard of any that went well with One Coulter, that did not also go well with Four, being placed as is here directed.

_P. 307_

_B Cole Delin et Sculp_]

The Proofs of a Plough’s performing well are these; _viz._ If it makes a Furrow of an equal Depth on the right Hand and on the left, and turns it off fairly: If, in its going, the Tail of the Share, and the Bottom of the Drock, bear against the Bottom of the Furrow; and if it goes easy in the Hands of the Holder, without pressing one Arm more than the other; then the Plough is certainly a good one.

The Ploughman who is accustom’d to a Two-wheel’d Plough, never suffers the Wheels to overturn, in turning out at the Land’s End, from one Furrow to another; for which Purpose, after he has lifted the Plough a little round, he has a Knack of holding up the Crow-staves with the End of the Beam, by pressing his Hand hard against the Handle, whilst the Plough lies down on one Side, until the Horses, the Wheels, and the Plough, come near to a Line in the Beginning of the Furrow; and then he lifts up his Plough, and goes on.

CHAP. XX.

_Of the Drill-Boxes._

The Drill is the Engine that plants our Corn and other Seeds in Rows: It makes the Chanels, sows the Seed into them, and covers them at the same time, with great Exactness and Expedition.

The principal Parts of the Drill are, the Seed-box, the Hopper, and the Plough, with its Harrow.

Of these the Seed-box is the Chief: It measures (or rather numbers) out the Seed which it receives from the Hopper: It is for this Purpose as an artificial Hand, which performs the Task of delivering out the Seed, more equally than can be done by a natural Hand.

It is described, together with some of its Appurtenances, in _Plates_ 2 and 3.

_The_ MORTISE.

As the Seed-box is the principal Part of a Drill, so is the Mortise the principal Part of the Seed-box.

The following Descriptions shew how this Mortise differs from a common Mortise.

Fig. 1. _Plate_ 2. shews both the upper and lower Edges of a Turnep-Seed-box, and the Manner how they are posited one over another, _a b c d_ is a rectangled Parallelogram, and shews the upper Edges (or Top) of the Mortise. _e f g h_, being a Figure of the same Denomination with the former, is the lower Edges (or Bottom) of the Mortise. The Line _e h_ is the Length of the lower Edge of the Hinder-end of the Mortise. _a d_ is the upper Edge of the Hinder-end of the Mortise, and posited just over the lower Edge of the same End. The Space between the Line _a b_, and the Line _e f_, shews half the Excess whereby the Bottom of the Mortise exceeds the Top in Breadth; as the Space on the opposite Side, betwixt the Line _c d_, and the Line _g h_, shews the other Half of that Excess, both which Halves, taken together, shew the whole Bevel (or Angle of Inclination) described in _Fig._ 2. That Part of the Line _a b_, from the Angle at _b_ to the Line _f g_, which intersects it, shews the Excess whereby the Top of the Mortise exceeds the Bottom in Length.

_Fig._ 2. Is the Mortise cut down by its Four Corners, and laid open. _a b c d_ is a Trapezium, with Two parallel Sides, and mark’d A, the right Side of the Mortise; its opposite Side _e f g h_, mark’d B, the left Side of the Mortise; the Areas of both being true Planes[261].

[261] Take care that these opposite Sides be sure to be true
Planes, especially all that Part of their Areas, that is before the
transverse Axes of their Ellipses herein after described; for should
they be otherwise, the Bevel of the Mortise would be spoiled, and
so would the Ellipses, and the acute Triangles, on the Sides of
the Tongue; which how necessary they are to be true, is shewn in
the proper Place. Workmen are very apt to fail in this when they
file by Hand, and make these Sides of the Mortise convex instead of
plane. Therefore this might be done with less Difficulty, and more
Exactness, with a File placed in a Frame, whereby it might move upon
a true Level without rising or sinking of either End.

_d i k h_ Shew the Fore-end of the Mortise, mark’d C. _a l m e_ shew the Hinder-end of the Mortise, mark’d D. _a d h e_ shew the Bottom of the Mortise already described in _Fig._ 1. If these opposite Sides and Ends were all raised up, until the Angle at _b_ join the Angle at _l_, and that at _m_ join _f_, and that at _g_ join _k_, and that _i_ join _c_, the Top of the Mortise would be formed, and the same with the Parallelogram _a b c d_, in _Fig._ 1. and then the intire Mortise of the Turnep Seed-box would appear in its true Form, standing upon its Bottom.

This differs from a common Mortise, in that it is impossible to fit it with a Tenon; because it is narrower above, and shorter below, as in _Fig._ 1.

The Areas, or imaginary Planes, of the Top and Bottom of the Mortise, are parallel to each other, but not equal.

Its Two opposite Sides are equal, but not parallel, by reason of their Inclination to each other upwards, which is the Bevel hereafter to be described.

The Two Ends are neither parallel nor equal, because the Hinder-end D is perpendicular to the Top and Bottom, and the Fore-end oblique, and therefore longer.

When Two opposite Sides, or Surfaces, are inclined to each other upwards, I call that Inclination a Bevel; but when they are inclined downwards, I call it a Bevel revers’d.

The Line _a e_, being the Bottom, or Base, of the Hinder-end D, by being longer than the Line _l m_, shews that the Mortise is bevel.

The Two prick’d Lines _m n_ and _l o_, with the Line _l m_, and Part of the Line _a e_, make a rectangled Parallelogram, which shews the exact Depth of the Mortise, and forms on each Side of it a rectangled Triangle, the one _m e n_, and the other _l o a_; which Triangles being similar and equal, and their acute Angles at _l_ and _m_ being each of Four Degrees, make the whole Bevel, or Inclination of the Sides of the Mortise, to be of Eight Degrees, their Hypothenuses being the same with the Sides of the Mortise.

This End D, being raised up to its Place, will be at right Angles with the Plane of the Top and of the Bottom of the Mortise; which, being both rectangled Parallelograms, prove that Bevel, or Angle of Inclination, to be the same from one End to the other of the Sides, which Sides are the Hypothenuses of those Two Triangles: But this could not be proved by the Triangles in the opposite End C; because the Bases being the same with the other, and having their Legs longer, the vertical Angles at _k_ and _i_ are more acute. The Legs are longer; because the End C, when in its Place, is not at right Angles with the Top and Bottom of the Mortise, as the End D is.

The next thing to be described in the Mortise, is the Bore, great Hole, or Perforation; which is best shewn in the Side of a Mortise of a Wheat-drill, being larger, as in _Fig._ 3. wherein _c e b d_ is the great Hole, and is a Section of an hollow Cylinder, that passes through the Mortise, with its Axis parallel to the Edges of the Ends of the Mortise: This Cylinder, being cut by the Side of the Mortise obliquely, and not parallel to its Base, is an Ellipse.

The prick’d curve Line is a Circle parallel to the Base of the Cylinder, and the curve Line _b d c e_ is the Ellipsis; and this Curve is more or less elliptical (or oval) in proportion to the Angle of Inclination, or Bevel, of the Sides of the Mortise.

Of this Ellipse the longest Diameter (or _Axis transversus_) _b c_ is at right Angles with the upper and lower Edges of the Sides of the Mortise.

Its shortest Diameter (or _Axis rectus_) _d e_, is the Diameter of the Cylinder, bisecting the _Axis transversus_ at right Angles in the Centre _a_; and is in this Figure one Inch and an half.

This Ellipse being concentric with the Circle, the Letter _a_ is the Centre of both.

The Semi-ellipsis _c e b_ is the Part of chief Use; and therefore the Edge must of Necessity be smooth, and without Flaws, as must the Surfaces of the Sides of the Mortise betwixt the Ellipse and the Fore-end.

The Tongue of the Seed-box (_Plate_ 3. _Fig._ 1.) differs from that in the Sound-board of an Organ (from which I took the Idea of it) in Shape, in Situation, and in the Manner of its being fix’d to the Mortise.

The Tongue, in the Organ, is on its Surface a long Square, or rectangled Parallelogram, a little broader and longer than the Mortise (or Grove) it shuts against; but this Tongue on its upper Surface, which is here turned downwards, being a Plane, is a Trapezium, of the same Shape with the Fore-end of the Mortise just now described, except that the Tongue has a less Bevel.

The Situation of that in the Organ is on the Outside of the Mortise, which it shuts by its Spring behind it, and opens immediately by the Finger of the Organist pressing down the Key to let in the compressed Air to its Pipes; but this Tongue is situate within the Mortise of the Seed-box, and placed almost, in a manner, diagonally; for, had it been placed like the other, the Seed getting betwixt it and the Edges of the Mortise, would not have given Way to its Shutting (as the Air does to the other), but have kept it always open; which would have render’d it useless for sowing of Seeds.

The Manner of fastening the Organ-tongue to its Mortise is by Parchment and Leather glu’d to its Surface, and also to the Sound-board, at its End which is opposite to that pressed open by the Key, and shut by the Spring; but this our Tongue is held within the Mortise, and moves on an Axis, which passes thro’ its upper and narrower End, which Axis is the Pin A (which must be exactly parallel to the Edge of the End of the Mortise), and also thro’ the Hole _f_ in _Fig._ 3. in _Plate_ 2. which is seen in its Place at A in _Fig._ 3. _Plate_ 3. and likewise through both Sides of the Mortise near their upper Edges, and as near the Fore-end of the Mortise as may be, without the Tongue’s rubbing against the said Fore-end.

The Breadth of the Tongue must be conformed to the Breadth and Bevel of the Mortise, and when it is on its Axis, it being raised tight up as far as the short prick’d Line _l m_ in _Fig._ 3. _Plate_ 2. being One-eighth Part of the great Hole, and being there, you see its upper Edges touch both Sides of the Mortise by their whole Length: Then it is rightly made: and by this touching both Sides of the Mortise tightly and closely, when raised up to that Degree, it appears, that the Two upper Edges of the Sides of the Tongue are inclined to each other in an Angle that is more acute, by about One-third, than is the Angle of Inclination of the Sides of the Mortise.

Hence, when the Tongue is let down to its Place, there will be on each Side of it an empty Space, betwixt it and the Mortise, of the Form of a very acute Triangle, whose vertical Angle is more or less acute, according as the Tongue approaches nearer to, or recedes farther from the Spindle.

This _Fig._ 1. _Plate_ 3. is the brass Tongue with its Back-side upwards. The Two outer Lines _a b_ and _c d_ are the Edges of the upper Surface (tho’ turned downwards in this Figure), which are inclined to each other, as afore-mentioned; but the Two inner Lines _e f_ and _g h_ are nearer to each other, whereby this under Surface is narrower than the upper: Both must be plain Surfaces, but the upper and its Two Edges very free from Flaws, and smooth, or polished.

The Reason why the under Surface is narrower than the upper, is to preserve the Bevel of the empty Triangle: For though the Bevel of the Sides of the Mortise would be sufficient for this, if both Sides of the Tongue were sure to keep equally distant from the Spindle; yet as the Tongue never is so tight on its Axis, but that sometimes one Corner of it may be nearer to the Spindle than the other, in this Case, that Side which is nearest to the Spindle would reverse that Bevel, so as to make the small empty Space that is betwixt the Mortise and the Tongue, wider above than underneath.

C C are the Two little Knobs that prevent the Spring from slipping to either Side, and are at the Distance from one another of the Breadth of the Spring.

_Fig._ 2. shews one Side, and the Thickness of the Tongue the other Side, being the same. _a b_ shews the polished Surface (being a true Plane), whereon the Seed runs down to the Spindle. _c d_ the Back-side, which lies turned uppermost in _Fig._ 1. _b e d_ shews one End of the hollow Cylinder of the Tongue, thro’ which its Axis passes.

The Length of the Tongue must be such, as will reach lower than just to touch the Bottom of the great Hole as a Tangent: for, if it be not longer than that, it might happen, that when the Mortise is empty of Seed, and the Tongue set up close, a Wheel might, in Turning, or otherwise, go a little backwards, and cause a Notch of the Spindle to take hold of the End of the Tongue, and tear it out of the Mortise: Therefore let the Tongue reach a little below the Spindle, as the pricked Line _g h_, in _Fig._ 3. of _Plate_ 2. doth.

As for the Posture in which the Tongue ought to stand in the Mortise, it is shewn by the Three pricked Lines in _Fig._ 3. _Plate_ 2. where the pricked Line _g h_ makes an Angle of Forty-five Degrees, being the nearest that it can stand to the Spindle; the pricked Line _i h_ makes a somewhat greater Angle, and it is a mean (or middle) Distance from the Spindle; and the pricked Line _k h_ is supposed to be its greatest Distance, where the Tongue makes its greatest Angle with the Top and Bottom of the Mortise. If the Tongue stood so obliquely as to make an Angle much less than Forty-Five, the Tongue would rise too much against the Bevel of the Mortise, and the Spring would have the greater Difficulty in returning it to its Place, when driven back by the Force of the Notches.

And beside, when the Tongue stood wide from the Spindle, there might be so much Room betwixt it and the Sides of the Mortise, that some Seeds might fall thro’ there.

The Steel Spring is D, properly placed upon the Back of the Tongue, in _Fig._ 1. _Plate_ 3.

At first, I made the Spring double, _i. e._ with Two Legs, in Imitation of that in the Organ, and fastened into its Tongue, much after the same manner as the Spring of the Organ is into its Tongue or Flap, which prevents the compressed Air from passing out of the Sound-board, except whilst the Key is thrust down by the Finger of the Player; but the Drill-spring requiring to be of a vastly greater Strength than that, I made it of Steel, of the Breadth of half an Inch, instead of Brass Wire: This performed very well, and several Drills are yet extant, that have only this Sort of Springs: Yet I found there was great Difficulty to set the Legs at their due Distance from each other; for their Seasoning would alter them from what they were, whilst the Steel was soft: They also took up too much Room in the upper Part of the Mortise. Then, to remedy these Inconveniencies, I made it single, with only one Leg, which by full Experience is found to be much better than the double one; it does not contain a Fourth Part of the Metal, and is most easily made, requiring none of that Trouble and Nicety that the double Spring doth. I shall therefore give a Description of the single Spring only.

B, the End of the Screw, which holds the Spring to the Tongue, thro’ a Hole near the upper End of the Spring; D, the Middle, against which the End of the Setting-screw bears.

Its Length is almost the whole Length of the Tongue; the End E reaching very near to the lower End of the Tongue, and the End B is as near the upper End of the Tongue; as it can be placed without touching the Cylinder of the Tongue.

The Breadth is usually about half an Inch; the Thickness must be in proportion to its other Dimensions, and according to the Degree of Stiffness required.

The longer it is, the thicker it must be, to have the same Stiffness; but the broader it is, the thinner it must be of the same Length; so that it is hard to determine its Thickness. It is made stiffer or stronger by being cut shorter; it is made weaker, or less stiff, by filing or grinding it either thinner or narrower.

The common Thickness is about that of a Shilling[262].

[262] Not quite so thick as a milled Shilling, but rather of an old
broad stamped Shilling, which is a little thinner.

The Degrees of Stiffness are measured in this manner; _viz._ Fix Two Boards together, leaving a Chink betwixt them, in one Place of an Inch long; lay the Spring (when seasoned across this Chink) with its Middle exactly over it; then put a String over the Spring, which may pass with both Ends thro’ the Chink, and tie so much Weight to the Ends of the String under the Boards, that will pull down the Middle of the Spring, till it touch the Chink, and is strait with both its Ends; This will shew the Degree of Stiffness. But note, That the Spring must be crooked, and bear only upon its Ends, with the hollow Side upwards.

If ten or a dozen Pounds Weight pull it down to the Board, it is a good Degree of Stiffness, for a large Box: We are not confined to be very nice or exact in the Degree of Stiffness; for by our Fingers pressing it, we that are practised in it, know well enough, whether a Spring be of a sufficient Degree of Stiffness, without weighing it; but for such who are unacquainted with them, it is best not to trust to Guess, but Weights; and to adjust the Stiffness to that of a Spring, that has been known to perform well.