the Dead Escapement. 19 



It now remains to point out the difference between the pallets as 

 drawn Fig. 1, Plate III, and Fig. 2 and 3, Plate IV. In Fig. 1, 

 Plate III, the angle of lead of the pallets as drawn, and the angles 

 they are led are one and the same, and equal to one another ; and, 

 consequently, the pendulum is led an angle equal to either of 

 these angles by the action of the wheel on each pallet. In Fig. 2 

 and 3, Plate IV, this is not the case, it is true the pendulum is led 

 an equal angle by the action of the wheel upon each pallet, the 

 angles B I C and D I E, Fig. 2 and 3, PI. IV, being in each figure 

 equal to each other, but the angles A I C and D I F of lead of the pal- 

 lets, are of necessity to enable the escapement to perform, drawn dif- 

 ferent from each other, and different from the angle the pendulum 

 is led ; the one being greater and the other less than that angle. 

 The consequence of this is that the length of the inclined planes 

 of the pallets is also very different, the one being much longer than 

 the other, which renders the fraction upon the two unequal, and 

 probably in the same ratio as the difference in their lengths, and, 

 consequently, the impulse received by the pallets must, from that 

 cause, independent of any other, be unequal. That this is an evil 

 of the first magnitude in the dead escapement, it would be a waste 

 of time to demonstrate ; it is only sufficient to observe, that the 



Dished to an angle sufficiently small to be led by the wheel an angle equal to 

 the angle the pallet AA is led with its angle drawn similar to Fig. 1. Plate 111., 

 and the two centers placed as in Fig. 2. Plate IV. 



In this figure, see Fig. 1. Plate IV., the angles the pallets are led, and con- 

 sequently the pendulum, though equal to one another, are less than in Figs. 

 2 and 3, same Plate, where they are purposely made to lead angles equal to 

 the angle led Fig. 1. Plate III., at the same time they are led angles equal to 

 one another. 



If, instead of the angle of lead of the pallet A A, Fig. 1, Plate IV. being 

 drawn as in Fig. 1. Plate III., the angle of lead of the pallet BB had been 

 so drawn, the angle of the pallet A A might equally be altered to suit the 

 action of the pallet BB, and similar effects would result as to the difference 

 between the angles of lead of the pallets as drawn, and the angles led by the 

 action ol the wheel on the pallets : and consequently the angle the pendu- 

 lum would he led, would be considerably greater than in Fig. 1. Plate 111. 

 instead of less, as in Fig. 1, Plate IV. 



C 2 



