WEIGHTS OF THE COMPONENTS OF A MIXTURE. 75 



(3) 



v ' 



REM. Instead of taking 1 Ib. as the unit of weight, as we 

 have heretofore done, it is sometimes more convenient to 

 take the weight of a unit of volume of the standard sub- 

 stance as the unit of weight ; thus, in the present Article, 

 we might have made 62 Ibs. the unit of weight, and found 

 the weights of the substances in terms of that unit. 



35. The Weights of the Components of a Mechan- 

 ical Mixture. When the specific gravities of the mix- 

 ture and its components, and also the weight of the 

 mixture are given, to find the weights of the compo- 

 nents. 



Let w, w', w" be the weights of the mixture and its com- 

 ponents respectively, s, s', s" their respective specific gravi- 

 ties ; and v, v', v" their volumes. Then we have 



w = w' + w", (1) 



and also v = v' -f- v" ; 



and, therefore, - = ^-' + ^ (Art. 34, Rem.). (2) 



s s s 



Combining (1) and (2), we obtain, 



