_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.