4ia Defcription of 



precifion than that given by common balances. There are 

 few of thefe which, when loaded with 500 pounds at each 

 end, arc decidedly fenfible of an ounce; and the fteel -yards 

 of C. Paul pofllfs that advantage, and cofc one half lefs than 

 balances of equal force. 4. In the laft place we may verify, 

 every moment, the juflnefs of the weights, by the tranf- 

 pofition which their ratio to each other will permit; for 

 example, by obferving whether, when the weight of one 

 pound is brought back one divifion, and the weight of one 

 ounce carried forwards eighteen div^fions, the equilibrium 

 Hill remains. 



If, inftead of ascertaining the weight of the merchandifc 

 in pounds, you wilhed to find it according to the new fvftem 

 in decagrammes, hectogrammes and kilogrammes, it will be 

 fufficient to fubftitute, for the ordinary weights, anaffbrtment 

 of three weights bearing; the above names. Thefe three 

 weights are the decuple one of the other; and the abfolute 

 weight of that called kilogramme, is to the abfolute weight of 

 that called pound, in the exacl ratio of thefe two quantities. 

 It may be here fcen, that, by adapting to the fteel-yard a 

 fyftem of three weights, we may arrive at the fecond decimal, 

 or the centiemes of the unity of the weights employed, and 

 even without adding or changing any thing in the divifion of 

 the beam. 



It is on this fimple and advantageous principle that C. 

 Paul has conftru&ed his universal J2eel-j>ard, which I am go- 

 ing to defcribe. It ferves for weighing in the ufual maimer, 

 and according to any fyftem of weights, ail ponderable bodies 

 to the precifion of half a grain in the weight of a hundred 

 ounces; that is to fay, of a decigramme in the weight of a 

 kilogramme, or, in other words, of a ten thoufaiuhh part. 



It is employed, befides, for ai'certaining the fpcciiic gravity 



of folids, of liquids, and can of the air iilelf, by precedes 



extremely fimple, and which do not require many fub-divi-, 



fions in the weights. This complete apparatus is reprefent- 



ed plate X. 



^ Y Tha 



