i S2 Method of Banking the Balance of a Thne-keeper. 



the balance to vibrate more than 36o degrees. Another 

 method is to have a piece moveable on a centre in one ok 

 the arms of the balance, and applvinc; itself a? a tangent to 

 the pendulum spring, which passes thvougrh a hole in the 

 piece. It has also a knee, which almost touches the plate, 

 and just passes free of a pin placed in it. But when the; 

 balance vibrates so as to approach its utmost limits, the ac- 

 tion of the spring, while in a state of unwinding, throws 

 the piece outward, so as to fall in the u .-^y of the pin, and 

 stop the balance from proceeding further. Another mode 

 is by a straight spring, screwed upon the plate, having a 

 hook at the end of it, into which a pin placed in ihe balance 

 strikes, when, as before, the pendulum spring, in unwind- 

 ing. Touches the straight spring, and inoves it a little out^ 

 wards. There is also a way of banking by means of a bolt, 

 which is thrown back by the pendulum spring, and made to 

 fall in the way of a pin placed in the rim of the balance. 

 These are the principal modes of banking now in usf, and 

 they do not differ malerialiy from one another in principle. 

 But the weiirht and friction of so many pieces on so delicate 

 an organ as that of a pendulum spring, are perhaps nearly 

 as hurtful to the time-keeper as the injmy it may sustain 

 when it is left without any bankmg whatever. 



1 am, sir, your most obedient servant, 



Will JAM IIardv, 

 Charles Taylor , Esq. 



In figures 1 and 2 (Plate III.) the same letters are placed, 

 to signiiy the same things. A A is the balance to which 

 the pendulum spring is fastened in the usual way. In one 

 of the crosses of the balance is placed a pin V, which stands 

 a little way above its surface; and when the balance is 

 caused to vibrate a complete circle, the pin in its motion 

 will describe the dotted circle POO, and just pass clear of 

 the inside of a projection formed on a cock B, which is 

 fastened on the plate by means of a screw. At about one- 

 fourth of a turn of the pendulum spring, reckoned from its 

 stud E, is placed a very delicate tapering piece of steel S, 

 ha^ ing a small hole in it, through which the pendulum 

 spring passes; and it is fastened to it by means of a pin, 

 and stands perpendicular to the curve of the sprinc". Let 

 the balance be at rest, as represented in fig. 1, the banking- 

 pin at P, and the banking-piece at .9. Suppose the balance 

 is made to vibrate from P towards O, when P arrives at t!ie 

 banking-piece s, it will pass it without touching, bccausq 

 its extremity ^ lies wholly within the circle traced out by 



the 



