But of whatever Sort or Dimensions one Notch is made, all the rest should be the same exactly; and consequently, the Interstices (or Intervals) between Notch and Notch, of which the Line _f c_, being an Arch of the Circle, is the Breadth, must be equal[265], and cannot be otherwise, if the Notches are all equal and equidistant, as they appear in the adjoining _Fig._ 5. which is a Section like the former, and shews Six Intervals, with their Six Notches, of the Size wherewith we drill St. Foin with high Wheels; but when we would drill very thin, it is better to have but Four or Five Notches instead of Six. [265] But these cannot be equal, unless the Notches are all of equal Breadth, and equidistant from one another; and if they are otherwise, the Seed will not be equally delivered to the Ground. _Fig._ 6. shews a Notch of the Spindle. _a b_ is the upper Edge of the Side of the Notch, being always an acute solid Angle. _c d_ is the Edge of its Bottom, being always an obtuse Angle. _e f_ is the Angle made by the Side and Bottom, and is always shorter than the aforesaid Two Edges, by reason of the Obliquity of the Two Ends; this Angle is never obtuse, except when the Bottom of the Notch is concave. These Three Lines must be parallel to the Axis of the Spindle. _Fig._ 7. is one End of the afore-described Notch; the Line _a b_ being joined to the Line _f d_ of _Fig._ 6. and the Line _a c_, being joined to the Line _b f_ in _Fig._ 6. would be the End of that Notch in its proper Posture; and then the Line _b c_, being an Arch of the cylindrical Spindle, would be the Edge of the upper End of the Notch. _a b c_, being the Area of this End, is a Plane, and, when in its Place, makes an Angle of Forty-five Degrees with the Axis of the Spindle. The other End is the same with this in all respects, except that, being opposite to it, it is inclined to it in an Angle of Ninety Degrees, at the bottom Angle of the Notch, at the Line _e f_ in _Fig._ 6. _Fig._ 8. is a Notch lying with its Ends near it, and is of the same Dimensions with those appearing in the Seed-box, _Fig._ 3.