The prick’d Lines are drawn all round the Carriage, thro’ the Centres of the Holes, and at equal Distance from the Bottom of the Carriage, which is an Inch and Three quarters, and the One-eighth of an Inch. This prick’d Line is a Direction how high to nail on the Ledgers G and H, whereon the Box is to stand; and the Distance the upper Surface of the Ledger must be above the prick’d Line, is the Semidiameter of the Brass Spindle; and the Thickness of the Brass Box above the Spindle, or which is the same thing, the Distance between the Centre of the great Hole of the Brass Seed-box, and the Plane of the Top of its Mortise, being half an Inch and half a quarter, strike a Line above the prick’d Line parallel to it, at this Distance above, and then nail on the Ledger, with its upper Edge at this Line. This, with its opposite Ledger plac’d in the same manner, will support the Box with the Axis of the Spindle of the Seed-box, at equal Height with the Centres of the Holes of the Carriage; so that if those Holes are parallel to, and equidistant from the fore Side and hinder Side of the Carriage, and the Axis of the Brass Spindle be placed in the like manner parallel to, and equidistant from the fore Side and hinder Side of the Box; then when the Box is thrust down in its Place, upon these Ledgers, and the wooden (false) Spindles are placed into their Holes, their Axis will fall into a strait Line with the Axis of the Brass Spindle, as they ought. _Fig._ 14. shews the Carriage laid open. A is its back Side lying down. B is its fore Side standing up. C is the square End of the left (false) Spindle, whereon a Wheel is to be put up to the Shoulders of the Spindle, quite close to the Ends of the Carriage. This Spindle, being an Inch and an half Diameter, is held in its Place, and kept from moving end-ways, by Two Wreaths; the one at _a_, bearing against the Inside of the End of the Carriage, the other Wreath at _b_, bearing against the left Side of the middle Piece; which Wreath keeps the Spindle from moving towards the right Hand, as the other does from moving towards the left. D is the square End of the other wooden Spindle, whereon a Wheel must be placed in the same manner as the other Wheel. This Spindle is kept from moving end-ways by Two Wreaths, in the same manner as the other Spindle is; but this right-hand Spindle, being that which turns the Brass Spindle by its Crank, which enters the Fork, should have its Wreaths of Brass, like those describ’d in _Fig._ 17. _Plate_ 4. Part of which Wreaths entering about Three quarters of an Inch into the Hole of the End and middle Part of the Carriage, being firmly screw’d on to the Spindle, prevent the Friction that would otherwise be betwixt the Wood of the Spindle, and the Wood of the Holes; which Friction wearing the Wood of both, would in time cause the Spindle to be loose in its Holes, whereby its Axis would deviate from the strait Line it should make with the Axis of the Brass Spindle,