C. Paul's new Steel-Yard. 41 1 



5, As the beam is divided only on one fide, it may have 

 the form of a thin bar, which renders it much lefs lufeepti- 

 ble of beinc bent bv the a&ion of the weight, and affords 

 room for making the figures more vifible on both the faces. 



6. In thefe Reel-yards the difpoiitipn of the axes is not 

 onlv fuch that the beam reprefents a mathematical lever 

 without weight ; but in the principle of its divifion, the in- 

 terval between every two divifions is a determined and aliquot 

 part of the diftance between the two fixed points of fufpen- 

 fion ; and each of the two weights employed has for its ab- 

 solute weight the unity of the weight it reprefents, multi- 

 plied bv the number of the divifions contained in the interval 

 between the two conftant centres of motion. Thus, fup- 

 pofing the arms of the fteel-yard divided in fuch a manner 

 that ten divifions are exactly contained in the diftance be- 

 tween the two conftant centres of motion, a weight to ex- 

 prefs the pounds on each divifion of the beam mull really 

 weigh ten pounds ; that to point out the ounces on the fame 

 divifions, muft weigh ten ounces, 8cc. So that the fame fteel- 

 yard mav be adapted to any fyftem of meafures whatever, 

 and in particular to the decimal fyftem, by varying the abfo- 

 lute heavinefs of the weights, and their relation with each 

 other. The application of this principle will be feen here- 

 after in tl»e defcription of the fteel-yard, to which C. Paul, 

 with trreat propriety, has given the name of un'iverjaljhel- 

 yard. 



But, to trace out, in a few words, the advantages of the 

 (leel -yards constructed bv C, Paul for commercial purpofes, 

 I fhall only obferve, 1. That the buyer and feller are certain 

 of the correctnefs of the inftrument, if the beam remains 

 horizontal when it is unloaded and in its ulual pofition. 

 2. That thefe fteel-.yards have one fuipenfion lefs than the 

 old ones, and arc fo much more fimple. 3. That by thefe 

 means we obtain, with the greateft facility, by employing 

 two weights, the exact weight of merchandife, with all the 

 approximation that can be defired, and even with a greater 



precifion 



