5 14 Of the Drill-Boxes. Chap. XX, 



great Hole as a Tangent : for, if it be not longer 

 than that, it might happen, that when the Mortife is 

 empty of Seed, and tfie Tongue fet up clofe, a 

 Wheel might, in Turning, or .other wife, go a little 

 backwards, and caufe a Notch of the Spindle to take 

 Jiold of the End or the Tongue, and tear it out of 

 the Mortife: Therefore let the Tongue reach a little 

 below the Spindle, as the pricked Line g h y in Fig. 

 3. of Plate 2. doth. 



As for the Pofture in which the Tongue ought to 

 Hand in the Mortife, it is fhewn by the Three pricked 

 Lines in Fig. 3. Plate 2. where the pricked Line 

 g h makes an Angle of Forty-five Degrees, being 

 the nearefl that it can Hand to the Spindle ; the 

 pricked Line i h makes a fomewhat greater Angle, 

 and it is a mean (or middle) Diflance from the 

 Spindle; and the pricked Line k h is fuppofed to be 

 its greateft Pittance, where the Tongue makes its 

 greatefl Angle with the Top and Bottom of the Mor- 

 tife. If the Tongue flood lb obliquely as to make an 

 Angle much lefs than Forty-Five, the Tongue would 

 rife too much againft the Bevel of the Mortife, and 

 the Spring would have the greater Difficulty in re- 

 turning it to its Place, when driven back by the Force 

 of the Notches. 



And befide, when the Tongue flood wide from 

 the Spindle, there might be lb much Room betwixt 

 it and the Sides of the Mortife, that fome Szedz 

 might fall thro' there. 



The Steel Spring is D, properly placed upon the 

 Back of the Tongue, in Fig. 1. Plate 3. 



At firft, I made the Spring double, i. e. with Two 

 Legs, in Imitation of that in the Organ, and faflened 

 mto its Tongue, much after the fame manner as the 

 Spring of the Organ is into its Tongue or Flap, 

 which prevents the comprefTed Air from palling out 

 of the Sound-board, -except whilft the Key is thruft 



down 



