Part 62

The first Idea that I form’d of this Machine, was thus: I imagin’d the Mortise, or Groove, brought from the Sound-board of an Organ, together with the Tongue and Spring, all of them much alter’d; the Mortise having an Hole therein, and put on upon one of the Iron Gudgeons of the Wheelbarrow; which Gudgeon being enlarg’d to an Inch and an half Diameter, having on it the Notches of the Cylinder of a Cyder-mill, on that Part of it which should be within the Mortise, and this Mortise made in the Ear of the Wheelbarrow (thro’ which the Gudgeon usually passes), made broad enough for the Purpose; this I hoped, for any thing I saw to the contrary, might perform this Work of Drilling; and herein I was not deceived.

As for placing a Box over this Mortise to carry a sufficient Quantity of Seed, it was a thing so obvious, that it occasion’d very little Thought; and an Instrument for making the Chanels, not much more; neither for applying Two Wheels, one at each End of the Axis, instead of the single Wheel in the Middle of the Axis of the Wheelbarrow.

At first my Plough made open Chanels, and was very rude, being composed of Four rough Pieces of Planks, of little Value, held together by Three Shoots, or Pieces of Wood, which held them at a Foot Distance one from the other; These Pieces, being cut sharp at Bottom, made the Chanels tolerably well in fine Ground. But I soon contrived a Plough with Four Iron Shares, to make Chanels in any Ground: This drew a Hopper after it, having Four Seed-boxes at its Bottom, carried on a Spindle by Two low Wheels, which had Liberty to rise and sink by the Clods that they pass’d over: The Seed-boxes delivered their Seed immediately into the open Chanels.

P. 344

W Thorpe sculp.]

This Plough and Hopper were drawn by an Horse, and the Seed, lying open in the Chanels, was covered sometimes by a very light Harrow, and sometimes by an Hurdle stuck with Bushes underneath it.

I soon improv’d this Plough to perform better, and to make Six Chanels at once, and sometimes a great many more.

This Plough and Hopper, with their Improvements and Alterations, are shewn in Plates 4. and 5.

CHAP. XXI.

Of the Wheat-Drill.

Fig. 1. in Plate 4. is the Drill-plough, which makes the Chanels for a treble Row of Wheat, at Seven-inch Partitions, and covers the Seed by the Harrow which moves on its Beams. A, is the Plank, Three Feet and an half long, Eight Inches and an half broad, one Inch and a quarter thick; its upper and under Surfaces are true Planes. B, B, the Two Beams, each Two Feet Four Inches long, Two Inches Three quarters broad, and Two Inches and a quarter deep, standing under the Plank at right Angles with it, and held up to it by the Four Screws and Nuts a₂ a₂ a₂ a₂ the one being at the same Distance from the right, as the other is from the left End of the Plank.

This Plough makes its Chanels by Three Sheats, and their Shares and Trunks; the First or Foremost of which Sheats stands under the Middle of the Plank, with Part of it appearing at b; and is fully describ’d in Fig. 2, where A is the Tenon, of a convenient Size, Two Inches broad between Shoulder and Shoulder, Three quarters of an Inch thick: It is driven into the Plank thro’ a Mortise, and pinn’d up by its Hole: It stands thus obliquely, and pointing forwards, that it may stand the more out of the Way of the Funnel. The Shoulder at a is a quarter of an Inch. The hinder Shoulder, from the Tenon to the Angle at b, is Three quarters of an Inch. The Depth of the Back of the Sheat, and Thickness of the Share, when it is on, from b to c, is Nine Inches and a quarter; and the Angle at c must be a right Angle, contrary to the Opinion of some, who fansy it ought to be acute, supposing that when this Angle is right, whilst the Seed is descending by the Back of the Sheat, the Plough, as it moves forwards, would get before the Seed, and so it might fall to the Ground behind the Trunk; but this Mistake is for want of considering the vast Disproportion between the Celerity of the Seed’s descending near the Earth, and the slow Progress of the Plough; the Seed descending at the Rate of Sixteen Feet in a Second of Time, and the Plough proceeding but about Three Miles an Hour, does not advance the Thickness of a Seed, whilst it is falling to the Ground by the whole Depth of the Sheat.

The Thickness of the Sheat is an Inch, at its upper Part. The rest of it is to be no thicker than the Breadth of the Share.

Fig. 3. is the Share, lying Bottom upwards. a is its Point. b the Socket, Three Inches long, Seven Sixteenths of an Inch broad. c is the Hole, by which it is fastened up to the Sheat. d is another Hole, which is never made use of, except when the Share, being fasten’d up by the other Hole, inclines to either Side; then we draw it right by a Nail driven into this Hole. e, e, are Two very small Notches, into which the Sides of the Trunk are jointed, to protect them from being torn out by the Earth or Stones that might rub against them, f is the Tail of the Share, which, when it is in its Place, will make the right Angle before described in Fig. 2. and from which Tail, to the Fore-part of the Socket, is the Length of the Bottom of the Sheat, viz. Six Inches and an half. The Breadth of the Share Three quarters of an Inch.

Fig. 4. shews one Side of the Share. The prick’d Line a e shews the Bevel of the Fore-end of the Socket, the upper Edge of which must bear upon the Fore-part of the Sheat below f in Fig. 2. and the other Part of the Share will bear against the Bottom of the Sheat, from d to c, and will be fastened up by a flat Nail, passing thro’ the foremost Hole of the Share, and entering the Hole g in the Sheat; which Nail being bended in the said Hole (which Hole should be at least an Inch Diameter) will hold the Share fast to the Sheat; and, by unbending this Nail, the Share may be easily taken off, upon Occasion, without damaging the Sheat. Note, This Hole in the Share ought to be wider below than above, and the Head of the Nail of the same Shape; or else, as the Share wears thinner, it might come off. The prick’d Line, near the Fore-part of the Sheat, shews where a Shoulder must be cut on each Side of it, because otherwise the Sheat, being thicker than the Breadth of the Socket of the Share, could not enter it: But take care, that the Share do not bear against these Shoulders.

Fig. 5. is one Side of the Trunk, being a thin Plate of Iron, and is often made of the Blade of an old Scythe: It is to be riveted on to one Side of the Sheat, to another of the same on the opposite Side, by Three Rivets passing thro’ them both, with the Sheat in the Middle of them; which Holes appear both in the Plate and in the Sheat. These thus riveted on do form the Trunk at the Back of the Sheat. The whole Breadth of this Plate is an Inch and Three quarters; but Three-eighths of an Inch being riveted on to the Sheat, there remains but an Inch and Three-eighths for the Trunk. The Length of the Plate is the same with the Depth of the Sheat and Share, except that it should not reach to the Bottom of the Share, by about the Thickness of a Barley-corn, to the end that it may not bear against the Ground, as the Share doth. The Notch at the Bottom of the Plate is that which answers the Notch in the Tail of the Share: The Corner of the Plate at a we make a little roundish, that it may not wear against the Ground.

This Plate thus riveted on the Sheat, and another of the same Form on the other Side opposite to it, compose the Trunk, which is Fig. 6. a d is the Edge a b of the Plate Fig. 5. b c is the like Edge of the opposite Side of the Trunk. A is the Back of the Sheat, which, together with the Tail of the Share when in its Place, makes the Fore-part or Length of the Trunk. The Thickness of this Back of the Sheat is the Width of the Trunk; and from this Back of the Sheat to the said Edges of the Plates, may be call’d the Depth of the Trunk. The upper Ends of these Two Plates a and b we spread open a quarter of an Inch wider, for half an Inch down, than the rest of the Trunk, for the more free Reception of the Seed from the Hole of the Funnel: We likewise take care, that the Two lower hinder Concerns of the Trunk do not incline to one another, to make the Trunk narrower than the Back of the Sheat, lest the Earth should be held in by them, and fill the Bottom of the Trunk.

Fig. 7. is one of the hinder Sheats, and appears, in part, at c in Fig. 1. It is fastened into one of the Beams by its Tenon, which, being driven into a Mortise, is pinn’d in by a Pin passing thro’ the Beam, and the Tenon cut off even with the upper Surface of the Beam: This Tenon stands more oblique than that of the fore Sheat, that there may be the more Wood between its Mortise and the Funnel, its hinder Shoulder being short: Its fore Shoulder at a must be very short, not above the Eighth of an Inch; but its Shoulder b Three quarters of an Inch. The Tenon is also shoulder’d on each Side, as well as before and behind. The Thickness of this Sheat should be greater than that of the Fore-sheat, because it is much narrower. The Depth of this Sheat, is less than the Fore-sheat, by the Depth of the Beam: It is, in all other respects, the same with the Fore-sheat, except that it and its Share are shorter. The Socket of this Share is but an Inch and One-eighth long, its Breadth half an Inch, and from the Fore-part of the Bottom of the Socket to the End of its Tail, but three Inches. Its Point from the Socket at Bottom is but Three quarters of an Inch, whereas the Point of the Fore-share is an Inch and Three quarters: There is but one Hole whereby the Share is fastened up to the Sheat. Its Trunk is no wider than the other; for we cut a Rabbet on each Side of the Sheat, that the Plates, which are the Sides of the Trunk, may come within Three quarters of an Inch of one another. Its Tenon, being narrower than the Tenon of the Fore-sheat, must be thicker than it.

The other Hinder-sheat, and all its Accoutrements, must be the same as this of Fig. 7.

The Workman must take care, that the Tenons of the Sheats be not made cross the Grain of the Wood; and therefore must make them of crooked Timber.

Fig. 8. shews how the Share is made of Four Pieces; of which a is a Piece of Steel for the Point, its larger End being cut bevel for the Shape of the Fore-end of the Socket. b is a Piece of Iron for the other End of the Share, from the Socket to the Tail: The other Two Pieces c and d are the Iron Sides, which, being welded on to the other Two Pieces, and cut off to the Length, form the Share, with its Socket, more exact than it can be made out of one Piece of Iron.

Now we return to the first Figure; where the Fore-sheat being fix’d up at equal Distance from each End of the Plank, and as near to the hinder Edges of it as can be, allowing room for the Funnel C to stand with the Fore-side of its Hole, to make one Surface with the Back of the Sheat, and for the hinder Part of the Trunk not to reach the Edge of the Plank, there must be also room for the Fore-standard D to stand perpendicular to the Plank, across the Tenon of the Sheat.

This Standard being close to the Fore-side of the fore Hopper, there must be so much room between it and the Hole of the Funnel, that the Seed may drop from the Seed-box into the Middle of this Hole. Thus much for placing the Fore-sheat.

Next, for the Two hinder Sheats; they must be placed at equal Distance from the Sides of the Beams, and so near to the hinder Ends of the Beams, that there may be room to make the Funnels in them, and their Tenons to come up between their respective Funnels E and F, and their respective Standards G and H, which Standards must be set perpendicular to the Beams.

The Distance of these Sheats from the Plank must be such, that the Wheels of the hinder Hopper may not strike against the Plank, nor against the Spindle of the fore Hopper; and the Semidiameters of these Wheels being Eleven Inches, there ought to be a Foot between the Centre of each Wheel and the Plank; but we sometimes cut Notches in the Plank, to prevent the Circle of the Wheels from coming too near the Plank.

For the nearer the hinder Sheats stand to the Plank, the better; but these Beams may be placed nearer to, or farther from the Plank, by their Screws and Nuts, at Pleasure.

These Beams must be set at such a Distance from one another, that the Shares may be Fifteen Inches asunder from the Inside of one to the Outside of the other.

To try whether all these Sheats and Shares are truly placed, set the Plough upon a level Surface; and then, if they be right, the Fore-share will touch the Surface by its Point and Tail, and likewise the hinder Sheats will do the same; except that some Workmen will have it, that the Plough goes better, when the Tails of the hinder Sheats are a Barley-corn’s Thickness higher than their Points; and then their Tails will want so much of touching the Surface.