3c8 Of the Drill-Boxes. Chap XX. 



from the Hopper : It is for this Purpofe as an arti- 

 ficial Hand, which performs the Tafk of delivering 

 out the Seed, more equally than can be done by a 

 natural Hand. 



It is defcribed, together with fome of its Appur- 

 tenances, in Plates 2 and 3. 



The Mortise. 



As the Seed-box is the principal Fart of a Drill, 

 fo is the Mortife the principal Part of the Seed-box. 



The following Descriptions fhew how this Mortife 

 differs from a common Mortife. 



Fig. 1. Plate 2. fhews both the upper and lower 

 Edges of a Turnep-Seed-box, and the Manner how 

 they are pofited one over another, a b c d is a rectan- 

 gled Parallelogram, and fhews the upper Edges (or 

 Top) of the Mortife. e j g h % being a Figure of 

 the fame Denomination with the former, is the lower 

 Edges (or Bottom) of the Mortife. The Line e h is 

 tho. Length of the lower Edge of the Hinder-end of 

 the Mortife. a d is the upper Edge of the Hinder-end 

 of the Mortife, and pofited juft over the lower Edge of 

 the fame End. The Space between the Line a b r 

 and the Line e /, fhews half the Excefs whereby the- 

 Bottom of the Mortrfe exceeds the Top in Breadth ; 

 as the Space on the oppofite Side, betwixt the Line 

 c d> and the Line g b, fhews the other Half of that 

 Excefs, both which Halves, taken together, fhew 

 the whole Bevel (or Angle of Inclination) defcribed 

 in Fig. 2. That Part of the Line a b> from the 

 Angle at b to the Line/ £, which interfecls it, fhews 

 the Excefs whereby the Top of the Mortife exceeds 

 the Bottom in Length. 



Fig. 2. Is the Mortife cut down by its Four Cor- 

 ners, and laid open, a be dls-d Trapezium, with 

 Two parallel Sides, and mark'd A, the right Sid^ 

 of the Mortife -, its oppofite Side e f g b y mark'd B, 



the 



