But observe, That the great Length of this Spindle requires it to be the larger; and we make it of an Inch and Three quarters Diameter, the other being only an Inch and an half: We therefore bore the great Hole or Cylinder of its Brass Seed-box a quarter of an Inch in Diameter larger than of the Brass Seed-boxes of the hinder Hoppers; and we commonly make a Notch more in the Circumference of this Spindle, because the Semidiameters of its Wheels must be as much greater than of the hinder Wheels, as is the Thickness of the Plank, and the Ends of the Limbers which are betwixt this Spindle and the upper Surface of the Two Beams.
We make all our Spindles of clear-quarter’d Ash, without Knots or Crooks; and when they are well dry’d, and made perfectly round, and of equal Diameter from one End to the other, by the Prong-maker, we pay a Peny per Foot for them at the first Hand, and they will now-and-then have something more for the largest Size; but we are only curious to have the middle Part of this long Spindle exact; for we graft on a Piece at each End, which does not require any Exactness: The Graftings are seen at a a at one End, and b b at the other End of the Spindle (in this [Fig. 21.]) by Four flattish Iron Rings driven on upon the grafted Parts, as they appear under those Letters in the Middle. Between each Pair of these Rings, we drive a small Iron Pin thro’ the Joints at c and at d, to keep the Grafts from separating end-ways; and if they are not tight enough, we make them so, by Wedges driven in betwixt them and the Spindle.
This fore Hopper is drawn by the Spindle, and the Spindle is drawn by the Two double Standards B and C, betwixt whose Forks it is placed, as appears in this Figure; the Distance between each Fork, or double Standard, being exactly the Diameter of the Spindle, so that the Spindle may have just room to rise and sink there, and no more.
The Hopper and Spindle are guided, or kept in their Place, from moving end-ways, by Two Wreaths screw’d on to the Spindle, the one at e, and the other at f; each of which Wreaths, bearing against the Surfaces of both the Legs of each double Standard, on the Sides next to the Hopper, prevent the Spindle and Hopper from moving towards either End; and yet admit the Wheels, or either of them, to rise and sink without raising either Side of the Plough, contrary to what would happen, if the Wreaths were placed on the Outsides of the Standards next to the Wheels.
We make these Wreaths a little different from the other Sort of Wreaths, which turn against the Holes; we make them of a greater Diameter, lest they should at any time get in betwixt the Legs of the double Standards, in case the Standards should be loose, or bend: Therefore we make the Diameter of each of these Wreaths, at least, Two Inches and Three quarters: We always make them of Wood, and of a peculiar Shape, taking off their Edges next the Standards, which Edges would be an Impediment to the Rising of one End of the Spindle without the other. So that, for making these Wreaths, we may form a Piece of Wood of the Shape of a Skittle-bowl (or an oblate Spheroid) having an Inch and Three-quarter Hole bor’d thro’ its Middle, and then cut by its Diameter (which is about Three Inches) in Two Halves, each of which will be one of these Wreaths; and they must be placed on the Spindle, with their convex Sides bearing against their respective Standards.
The Diameter of the fore Wheels is about Thirty Inches, as the Diameter of the hinder Wheels is about Twenty-two.
The fore Spindle should be of such a Length, that its square Ends, E and F, may come out Three or Four Inches farther than the Hubs (or Stocks) of the Wheels; so that there may be room to shift the Wheels towards either End, for making several Sets of Notches, for the Use of the Seed-box.
Observe, Tho’ the fore Hopper is drawn by its Spindle, yet the hinder Spindle is drawn by its Hopper.
The Reason of this great Distance between the Two fore Wheels is not so much for their serving as Marking Wheels to this particular Drill; which being drawn only upon a Ridge, its Top is a sufficient Direction for leading the Horse to keep the Rows parallel to one another, if the Ridges are so; but if the Wheels were much nearer together than they are, and yet more than Six Feet asunder, the Wheels going on the Sides of the next Ridges would be apt to turn the Drill out of the Horse-path towards one Side, not permitting the Drill to follow directly after the Horse; and if the Wheels should stand at Six or Seven Feet Distance from one another, then they must go in the Furrows which are on each Side of the Six-feet Ridge: This would occasion their Hopper to bear upon the Plank, which would carry the Wheels above the Ground, and no Seed would be turned out of the Hopper, unless the Wheels were of an extraordinary Height[268]; and the Height requir’d for them would be very uncertain, some Furrows being much deeper than others; but the Tops of contiguous Ridges are generally of an equal Height, whether the Furrows betwixt them be deep or shallow; for we seldom make Ridges of an unequal Height in the same Field: Therefore there can be no need to change the Height of our Wheels, that are to go upon the Middle of the Ridges; but if they went in the Furrows they must be of a different Height when used for drilling of high Ridges, from what would be required when used for drilling low Ridges.
[268]Notwithstanding the Reasons given, and that I have never used Wheels of such an Height as might be necessary for going in the Furrows, yet it may not be amiss to try such; because with them the Spindle needeth not to be more than half the Length of one that is carried by low Wheels: And high Wheels will allow the Funnel to be much larger, so that altho’ the Spindle go higher from it, no Seed will drop beside a large Funnel; but there is not room for a large one under low Wheels.