if the Bynanofneier. 403 



]VT, a focket riveted on the plate J, in which the upper 

 Jrivot of the lever turns. 



N, N, N, fmall cylindric pillars that fupport the covering 

 plate, which is fixed to them by three fcrews. 



O, an iron rack, on the lower part of which the feet muft 

 be placed when it is intended to try the ftrength of a per- 

 fon's body. 



P, a double handle of wood, with an iron hook, to be 

 held at the fame time in the two hands. 



Q, a double hook made of iron, one end of which is to 

 be hooked to the end of the fpring, and the other to a rope 

 faftened to a (lake, as at c, when experiments are to be made 

 on the ftrength of horfes, or others, that require the dyna- 

 nomcter to be fupported by hooks. 



R, the manner of holding the dvnanometer to afcertain 

 the ftrength of the hands. 



S, polition of a man when trying the ftrength of his 

 reins. 



T, difpofition of the dynanometer to try the ftrength of 

 a horfe or any other draught animal. 



The effects of this machine may be thus explained : If a 

 perfon prefles on the fpring with the hands, or draws it out 

 lengthwife, by pulling the two extremities in a contrary di- 

 rection, the two fides of the fpring approach each other; 

 and in proportion as they are brought nearer, the fmall 

 lever of the mechanifm pufties before it the index, which, 

 by the tightnefs with which it is fcrewed in its place> 

 will remain at the point to which it has been brought by 

 the pin d, in conlequence of the force acting on the fpring. 



The mufcular force of the arms, or rather the ftrength of 

 the hands, may be tried by laying hold of the two fides 

 of the fpring nearcft to the centre, as may be feen figure 

 R ; fo that the arms may be a little ftretched, and inclined 

 downwards, almoft at an angle of 45 degrees. This pofi- 

 tion, which appears themoft natural, is alfo the mod con- 

 venient for a man to act with his full force. It is to be 

 Dd2 recollected, 



