I did not think it necessary to describe the Manner of making Drill-wheels any otherways than by shewing them in the Plates; but I will observe here, that they are to be made very light: One of mine, that is 30 Inches high, weighs Five Pounds and an half; it has a Circle or Ring of Iron, whose Depth is half an Inch, and its Thickness a quarter of an Inch; also very thin Iron Stock-bands to hold the Nave or Stock from splitting. The Circle is held on the Spokes by small flat Iron Pins on each Side; and each Spoke has a Ring of Iron to secure its End from being split by driving in of the Pins. We also make the Drill-wheels less concave than other Wheels are.
One Reason why the hinder Shares are shorter than the fore Share (and consequently the fore Part of their Sheats less oblique) is, that they may be set the nearer to the Plank; and I have had a Drill with Five Shares in the Plank, Fourteen Inches asunder, and Four of these hinder Sheats following in another Rank, whose Shares were less than Three Inches long; so that their Beams were set so far forwards, that one Hopper (by a Contrivance that carried the Seed forwards to the fore Rank, and backwards to the other Rank) supply’d the Seed to both Ranks of Trunks, and planted St. Foin in Rows Seven Inches asunder, when the Ground was too rough to be planted with Rows at that Distance by one Rank of Shares.
It may be objected, that the fore Part of these hinder Sheats might not be oblique enough to raise up the Strings of Roots or Stubble, which might come across them in their Way; but this Inconvenience is remedied by the greater Obliquity of the fore Sheat (or Sheats), which clears the Way for the hinder Sheats, by raising out of the Ground such Strings, &c. which might annoy them; especially, in this Wheat-drill, where the fore Share so clears the way of the hinder Shares, that they can take hold of no String in the Ground, except of the Ends of such which the fore Share has loosen’d; and they hanging faster in the Ground by their other Ends, the hinder Shares slip by them without taking hold of them; and the Harrow-tines, going after so near to the Chanels of the hinder Sheats, by the same means escape also from hanging in such Strings.
The Reasons for placing the One Share and One Hopper before, and the Two behind, in this Wheat-drill, are so many, and so obvious, that it would be but losing of Time to mention them.
The Limbers G and H, we make of Aspen, Poplar, or Willow, for Lightness; we make them as small and light as we can, allowing them convenient Strength; and the shorter they are, the more exactly the Drill will follow the Horse, without the Hand of him, that follows the Drill, whose chief Business is, with the Paddle to keep all the Shares and Tines from being clogged up by the Dirt sticking to them, and also to observe whether the Seed be delivered equally and justly to all the Chanels.
These Limbers should approach so near together at their fore Parts, near the Chain, that there may be none or very little room betwixt the Limbers and the Horse; and therefore must be nearer together for a very little Horse than for a great one: The Horse, which I have used in all my Drills for these many Years past, is a little one, about Thirteen Hands high; and the fore Part of my Drill-limbers are Twenty Inches wide asunder at the Chain.
At g on the Outside of the Limber G, is a small Staple driven in, having one Link on it, which holds a small Hook, which, taking hold of different Links of the very small Chain I, raises or sinks the fore Part of the Plough to different Heights. But take care to set it at such a Degree, that the fore and hinder Share may go equally deep in the Ground; and when they do so, the fore Part of the Limbers ought to be higher than the Traces which draw them.
At h in the Limber H, is driven another Staple, which holds the other End of the Chain; or else, instead of a Chain, we may make use of a Piece of Cord, one End of which put thro’ this Staple, and ty’d to the Limber, and a Piece of Chain of half a dozen Links, fasten’d to the other End of such a Cord, will serve as well as a whole Chain, for raising and sinking the Limbers.
He who can by these Directions make this Wheat-drill, may very easily make any other Sort of Drill, for planting any Sort of Corn, or other Seeds that are near about the Bigness of Seeds of Corn: He may make it with a single Row of Sheats, by placing as many of these fore Sheats as he pleases in the Plank, which maybe longer or shorter, as he thinks fit; and he may add a Beam betwixt every Two of them, with a Sheat in it, like these hinder Sheats; and then the Drill will be double, having Two Ranks of Shares. But I must advise him never to make a Drill with more Shares than will be contain’d in Four Feet Breadth, that is, from the outermost on the right Hand, to the outermost on the left Hand; for should the Drill be broader, some of the Shares might pass over hollow Places of the Ground without reaching them, and then the Seed falling on the Ground would be uncover’d in such low Places.
To a Drill that plants upon the Level, Marking-wheels are necessary, to the End that every Row may be at its due Distance: As in a Drill with Five Shares, for planting Rows Eight Inches asunder, Four of the Five cannot err, because Four equal Spaces are included betwixt the Five Shares; but the Fifth (which we call the parting Space) being on the Outside unconfin’d, would scarce ever be equal, were it not kept equal by the Help of the Marking-wheels. The Rule for setting of these is thus: We compute altogether the Five Spaces belonging to the Five Rows; which being in all Forty Inches, we set the Marking-wheels Eighty Inches asunder, that is, double the Distance of all the Spaces, each Wheel being equidistant to the Middle of the Drill, which Middle being exactly over the Horse-path, when the Drill is turn’d, the Horse goes back upon the Track of one of these Wheels, making his Path exactly Forty Inches distant from his last Path: By this means also the Rows of the whole Field may be kept equidistant, and parallel to one another; so that it would be difficult for an Eye to distinguish the parting Rows from the rest.