50 
by evaporation, distilled water added, and the volume of 
this solution of ferric chloride made up to about 50 c.c. 
The weight of this solution was found to be 56' 0955 gram. 
1 gram, therefore contains *0356 gram. Fe as Fe 2 Cl 6 . 
To verify this calculation : 2-529 gram, solution were pre- 
cipitated by ammonia, and the iron estimated as oxide in 
the usual way. 
Found. Calculated. Difference. 
Fe. ‘0896 -0901 *0005. 
A series of determinations was then made in which the 
oxide was precipitated by ammonia in presence of sodium 
chloride, which was selected as a typical saline compound. 
The results are tabulated below : — 
a. 
Weight of 
Solution 
taken. 
2-556 
Weight 
of Fe. 
contained. 
00911 
Weight 
Nad 
added. 
2-000 
Weight Fe. 
from Fe 2 0 3 
obtained. 
0-0938 
Error. 
•0027 
Notes. 
Wash Water 350 cc. 
pptd. in boiling so- 
lution. 
b. 
2-574 
0-0917 
2-000 
0094 
■0023 
Wash Water 250 cc. 
pptd. in boiling so- 
lution. 
c. 
2-579 
0-0919 
1-000 
00945 
•0026 
Wash Water 125 cc. 
pptd. in boiling so- 
lution. 
d. 
2-542 
00906 
2-000 
00952 
•0046 
Wash Water 175 cc. 
NaCl added after 
pption. 
G . 
2-480 
00884 
2-000 
0-0941 
•0057 
Wash Water 175 cc. 
pptd. in cold solu- 
tion. 
/• 
2-587 
0-0922 
2-000 
00994 
•0072 
Wash Water 375 cc. 
pptd. in c old solu- 
tion. 
In the above determinations no more than the ordinary 
precautions were adopted, i.e ., the precipitate was washed 
with boiling distilled water from 15 to 30 times until the 
washings no longer gave an alkaline reaction. 
In some cases the precipitate of oxide was redissolved 
after weighing, in HC1, and the iron precipitated as sulphide. 
The filtrate from the latter was evaporated and the residue 
ignited — in every case a considerable fixed residue of sodium 
chloride was obtained. 
A similar series of determinations was then made with 
ferrous ammonium sulphate ; weighed quantities were oxi- 
dised with nitric acid and ferric oxide precipitated by 
ammonia in presence of sodium chloride. The results 
