GtlAHAM'S ESCAPEMENT. 133 



Fig, 3^ Shows upon an enlarged scale part of the barrel E, Description of 



and some of the chain lying in its proper position the crane by 



. ,. . , J ^ 1 •, • J. references to 



m one of the spiral grooves, or channels : it is to ^^^ nX^^t^ 



be noted that the lower edge of one link lies in 



the groove, and the next link upon the surface of 



the barrel, and that by this means the chain is 



prevented from twisting iu winding upon the 



barrel. 



Fig, 4y Shows a section of part of the barrel E, in order" 



to point out clearly the manner in which one link 



lies within it, the other link on its outside ; it is 



contrasted by Fig, 7, the old method of working 



chains*. 



VII. 



Construction of the Anchor and Pallets in Graham's dead 

 beat Escapement, Bi/ Mr. J. Bennett. 



To Mr. Ni€hoi.son. 

 Sir, 



S I have always found the following method of draw- 

 ing the dead beat escapement for clocks very useful and 

 correct in practice, if you think it deserves a place in 

 your valuable Journal, by inserting it, some assistance 

 will probably be afforded to workmen in that branch of 

 mechanics: and you will oblige 



Tour's, , 



Norwich, J.BENNETT. 



^th August J 1806. 

 ft 

 Draw the line AB (fig. 4. pi. III.) on which describe the Construction 

 circle B the size of the intended swing wheel: then, accord- °^j nJJ^for 

 ing to the number of teeth the pallets are intended to scape Graham's dead 

 over, say. As 60+ is to 360, so is double the number in- ^^^'• 



* Certificates of the highest respectability are mentioned in the 

 Transactions, which were sent to the Society in proof of the ad- 

 vantages derived from sixteen months daily work of chains applied 

 in this method. 



t The first proportion must always be double the number of 

 jf eth in the swing wheel. 



tended 



