a 
Potassium as an Oxydizing mixture. 201 
At the suggestion of Prof. Storer, I have examined other por-. 
tions of the same sample of bichromate of potassium, with the 
view of discovering, if possible, the sources of error which viti- 
ated the foregoing analyses. 
A quantity of the bichromate was heated until it fused, the 
cold mass powdered and several portions of it, weighing from 
one to two grams each, were taken for analysis. Hach of the 
weighed quantities of bichromate was dissolved in distilled water, 
the solution was heated nearly to boiling and a lump of acetate 
of sodium twice the volume of the bichromate of potassium 
taken was thrown into the hot liquor. Acetic acid was then 
added to strongly acid reaction, and afterward a solution of 
chlorid of barium, with occasional stirring, until no more pre- 
cipitate was formed on the further addition of chlorid of ba- 
: filtrate proper, 
that is to say, the clear liquor decanted from the precipitate, 
No. of the rms. of rms. of Percenta 
Experiment, K,0, 2Cr03 BaO, CrO, of Chromium 
taken. found. found. Theory 
1 1°0095 1°7301 35°47 
2 1°0175 1°8444 37°58 ya 
3 15456 27541 s7-74 7 SSR 
4 1°5020 2°5696 35°49 
3 ' 
Experiments 3 and 4 were carried out side by side, and every 
effort made to treat them exactly alike. 
Jour. Sci.—Sxconp SERIES, VoL. XLVIII, No. 143.—Sepr., 1869. 
14 
