200 =F. HH. Storer on Nitric Acid and Chlorate of 
alent to 68°65 per cent of chromium in the oxyd taken instead 
of the theoretical 68°62 per cent. 
III. 0°113 grm. of the dried hydr containing 0-0707 grm 
of the anhydrous oxyd of chromium was mixed with a quantity 
of nitrate of magnesium,—prepared by dissolving carbonate of 
magnesium in nitric acid —before the treatment with nitric acid 
and chlorate of potassium, 0° m. of chromate of barium 
was obtained. In other words, 68°60 per cent of chromium in- 
stead of the 68°62 per cent required by theory. 
IV. 0°114 grm. of the dried hydrate of chromium, containing 
0:0713 grm. of the anhydrous oxyd, was mixed with nitrate of 
aluminum,—prepared by dissolving hydrate of aluminum in 
nitric acid—before the treatment with chlorate of potassium. 
0-2356 grm. of chromate of barium, was obtained. That is to 
say, 68°31 per cent of chromium instead of 68°62 per cent. 
V. A small quantity of chrome-iron-ore was ground to very 
fine powder and treated in a dish with nitric acid and chlorate 
of potassium as above described. At the end of half an hour, 
that portion of the ore which still remained undissolved was 
washed with water, dried, fused with a mixture of carbonate of 
with water ; but the solution thus obtained gave no reaction 
for chromium when tested for that substance. 
It appears from the foregoing experiments that chromium 
can be readily estimated, in “this | way, in presence of aluminum 
and magnesium. The process can doubtless be employed a “ 
for separating chromium from, iron, cobalt, nickel and 2 
As a matter of course, special care must always be taken to a 
ploy reagents which are absolutely free from any contamination 
of sulphuric ac aci 
April, 1869. 
On the use of hee yf — in apace Analysis ; 
H. Ricuar 
A sample of pure rea of ser ae examined simul- 
taneously by three of the students in the Institute’s laboratory 
’ 
gave the fol owing discordant results. The method of analysis 
was similiar to that described below 
Name of Grms. of Grms. of Percentage 
experimenter. K,0, 2Cr0,;_ ~—- BaO, CrO, of Chromium. 
taken, found. Found. Theory. 
N. F. Merrill, 0516 08640 34°67 35°56 
F. P. Pearson, 0500 08788 span. & * 
C. E. Ave i moe 36°31 - 
“é “ ee z 36°24 “w 6 
