C Paul's new StecI-larJ. 41J 



The beam A B of this fteel-yard is conftrucled on the fame 

 principles as the commercial fteel-yard, but of much fmaller 

 dimensions,*. The {hears are fufpended by a fcrew to a crofs 

 bar of wood fnpported by two pillars, which reft on the two 

 extremities of a fmall wooden box furniiTied with three 

 drawer-, and which ferves as the ftand of the apparatus. 

 This beam is divided into 200 parts, beginning at its centre 

 of motion. The division is differently marked on the 

 two faces : on the anterior face the numbers follow each 

 other from 10 to 200, proceeding towards the extremity ; and 

 on the other face, reprefented apart at F, the numbers are 

 marked in the opponte direction. I {hall foon explain the 

 ufe of this difference in the order of numeration. 



The fmall frame G is deftined to prevent the ofcillation of 

 the beam, and it is placed at the proper height by means of the 

 nut and fcrew by which it is fufpended. Above the beam 

 is feen a fmall crofs bar of brafs, fufpended by its two extre- 

 mities from the crofs bar of wood. Different weights are 

 hooked to it, each having its particular value marked on it. 

 , in the laft place, a fmall mercurial thermometer having 

 the two moft ufual divifions, and defrined to point out the 

 temperature of the air ant! the water during the experiments. 

 The axis of fufpenfion of the fteel-yard refts upon two beds 

 of very hard well-polifhed fteel. The cafe is the fame, but in 

 a revcil'cd fitiu.tion, with the axis which fupports the hook C, 

 that ferves for fufpending different parts of the apparatus ac- 

 cording to the purpofe to which it is to be applied. 



When you wifh to employ it as a common (ieel-yard. you 

 fufpend from it the brafs (hell E, which is an exact counter- 

 balance for the weight of the beam when unloaded. The 



• A drav ing of C. Paul's Ccmmirci .' ' D l-yard was fubjoincJ to th's 



;•-, we have; beep obliged] 



r^ : ici t e one v.- e I avc can lid tx> be engraved will 



.-.y iuiui'.i idoaof.it> lince the principles of the conftruftion of both 



the i French 



JLdlttrf. 



latter 



