Specific Gravities. 313 



Suppose a compound of gold and silver to have a specific 

 gravity equal to 14, that of pure gold being 19,3, and that of 

 pure silver 10,5 ; we have 



S 19,3, S' = 10,5, S" = 14 5 

 and consequently, 



S" S' = 3,5, 

 S S' = 8,8, 

 S S" = 5,3 ; 



whence, by the formula, the proportional weight of gold will be 



3,5 X 19,3 67,55 _ 

 8,8 X 14 " 123,2 



The formula for the value of y gives for the proportional weight 

 of silver 



5,3 X 10,5 J35,65 __ Q45 

 8,8 X 14 " 123,2 



whatever* c may be in each case. 



Where the proportion of the ingredients by bulk or measure, 

 instead of by weight, is sought, as in the case of liquids, the 

 process is shorter. Calling 6, &', the bulks of the ingredient 

 corresponding to the specific gravities , $', as the weight is 

 equal to the bulk multiplied by the specific gravity, and the 

 weight of the compound is equal to the sum of the weights of 

 the ingredients, we have 



S" X (b + 60 or S" b + S" I' = S b + S' &', 

 whence 



or 



I (S" S) = V (S f S") ; 

 that is, 



6 ; : V : : S' S" : S" S. 



Suppose a certain spirituous liquor to have a specific gravity 

 equal to 0,93, that of highly rectified alcohol or pure spirit being 

 Meek. 40 





