304 Description of an hvproved Eight-Dat/ Clock. 



chanic who wishes to manufacture clocks on this principle. 

 The main wlieel A, with seventy-eight teeth, is to act in a 

 pinion ot" eight leaves B. The pin-wheel C should be large, 

 so that the pins on vvhich the pallets D and the locking G 

 act, may be flung as far from the centre as possible; which 

 pins may be eight or sixteen in number. It eight, the pen- 

 dulum E should be about nine inches long, and it will vi^ 

 brate twice betwixt each blow of the hammer; but if six- 

 teen pins are put in the w heel, the pendulum must be about 

 three inches' long, and will make four vibrations betwixt 

 each blow. The pins for drawing the hammer must be 

 €iaht in number, and be fixed in a circle of about half the 

 diameter of the aforesaid pins. The locking plate is on the 

 main wheel. The stop is ao-aiust the pins on which the 

 pailc's act, and may be discharged by a llirt-piecc. 



" As I have described the model, I beg leave to point out 

 the method of striking a clock by the common pendulum, 

 true seconds, without any additional pendulum or pallets 

 for the striking part. 



" Fix a cantrite wheel with sixty teeth on the same arbor 

 with a swing wheel of thirty teeth. Now, suppose a strik- 

 ing-part to be made in the common v/ay of making an eight- 

 day clock, so far as the pallet pinion, leaving out the warn- 

 ing; and fiv pinions. A crank- piece must be fixed on the 

 pallet pinion, which must come into contact with the can- 

 trite wheel, which is fixed on the swing-wheel arbor. Then 

 suppose the clock to be set a-going, and the rack discharged, 

 the pallet pinion will make a revolution on every vibration 

 of the pendulum, by which means a clock will strike se- 

 conds as true as a pendulum vibrates, which I hope will be 

 considered as useful for the purposes 1 have described. I 

 also beg leave to observe, that a great advantage arises in 

 both the above machines from their not being liable to foul, 

 as the stroke is given by the certain and regular vibration, 

 instej.d of the uncertain motion of the fly. Its advantage 

 likewise depends on the cleanness of the work ; and church 

 Clocks will be much benefited from the decrease of weight." 



LIV. Jc' 



