CRITICAL EXPERIMENTS FOR DETERMINATION OF POTASSIUM, ETC. 613 



II. Series : with 82 per cent. Salt. 



Comprising again 4 analyses, each made with about 0*52 grm. of chloride of 

 potassium. 



Taking " T " as symbol for the weight of chloride of potassium found in 

 an analysis, from the chloroplatinate by the Committee's factor, and A as 

 designating the corresponding weight of chloride of potassium taken, we 

 had : — 



Analysis, (1) (2) (3) (4) 



T-Ainmgs., . . . -1-49 -090 -121 -1-22 



Volume of platinic filtrates, 4 - 8 4"8 48 5 - c.c. 



These, united with the alcoholic washings, contained in all 971 mgs. of KC1, 

 or 2 - 43 per analysis, or 500 mg. per c.c. of aqueous platinic nitrates. 

 Uniting the four analyses into one, we had — 



A = 210646; A = 2*09675; = 6-8771; 



T = 210164; T-A= -4-82 mgs.; T-A = +489 mgs. 



A : C = 0-30630 ; A : C = 0-30489. 



From (1), (3) and (4). Total platinum =p = 20689 ; (platinum from (2) lost). 



A =1-57274. 

 A :p = 0-76018 ; (p : A ) K 2 C1 2 = 19624. 



III. Series: 33*3 per cent. Salt. 

 Four analyses, each with about 0*215 grm. of chloride of potassium. 



Analysis, 



(i) 



(2) 



(3) 



(4) 



T— A (in mgs.), . 



-0-66 



-048 



-0-88 



-044 



Volume of platinic filtrates, 



5-8 



5-9 



53 



5-3 c.c. 



From all the nitrates, including alcoholic, KC1 recovered as usual, and 

 found, = 910 mgs., or 2*28 mgs. per analysis, or 0408 mg. per c.c. of aqueous 

 platinic filtrates. 



Uniting the four analyses into one, we had — 



A = 0-86132; A = 0"85222; C = 2-8104; ^ = 1-1259 ; 



T = 0-85886; T-A= -2-46 mgs.; T-A = +6-64 mgs. 



A : C = 0-30648; A : C = 0-30324; A : p = 0*75692* (p : A ) K 2 C1 2 = 197*09. 



The precipitate obviously was impure, and included foreign chloroplatinates. 

 Before passing on, let us summarise the principal result of our test 

 analyses by the two methods. 



A. Finkener's. 

 Each set of analyses united into one. Column I. refers to the respective 

 page of this memoir ; Column II. specifies the set of analyses referred to ; 

 Column III. the percentage of KC1 in the salt analysed. 



