Mr. G. Bird's Observations on indirect Chemical An ali/sis, 231 



certain the exact proportions in which the two bases exist. 

 We take two exactly equal portions of the mixture, and sa- 

 turate one with sulphuric acid, the other with hydrochloric 

 acid. Now, if the weight of the sulphates thus obtained is 



2*978656 = h. 

 Do. of hydrochlorates thus obtained is 2*479338 = h'. 

 From their atomic weights we get the following proportions. 



For sulphate of potassa. For sulphate of soda. 



•=i|S = ■■•'»- -ilSI — 



For hydrochlorate potass. For hydrochlorate soda. 



Then by the equations 3. and 4. we have 



Potass X — 0*5 



Soda y = 0*9. 



It is evident that mixed carbonates, acetates, &c. of potass 

 and soda may be used in the above process quite as easily as 

 the pure bases, with which we rarely have to deal in analysis. 



The above calculations become simpler, if, instead of using 

 two portions of the mixed bases, we take but one and convert 

 it into sulphates, if not already in that state ; then knowing 

 the weight of the mixed salts, we determine the quantity of 

 sulphuric acid present by means of chloride of barium ; then 

 the weight of the mixed sulphates minus the quantity of sul- 

 phuric acid gives us the weight of the mixed bases : let this 

 weight be called 1i in the equation (2.), and then consider a' 

 and U as equal to 1 ; ^ retaining its former value. The sim- 

 plification of the formulae thus proposed by PoggendorfF will 

 be rendered more obvious by copying them in this improved 

 state; the only calculations required after determining the 

 weights of the mixed sulphates and sulphuric acid being 



h^h'b hJa-^h 



X = 7— y = J— • 



a—b ^ a—b 



Even these calculations may be still further reduced if we 

 substitute the following equation for finding the value of 3/ ; 

 for that proposed by Poggendorff, 



h'-x = t/y 



and when we recollect that (in the case of potass and soda) 

 a, and b, are constant quantities, we shall scarcely desire 

 greater simplicity of calculation. As an example of this im- 



