54 
alkaline earths ; but that the latter may be effectually sepa- 
rated from iron by precipitating this metal in the form 
of the basic acetate. 
(4). That ferrous sulphide does not exert this adhesive 
action upon salts in solution, and is therefore, where the 
circumstances of the analysis permit, the best form in which 
to separate iron from the other metals which accompany it. 
In conclusion, I would briefly call attention to the re- 
searches of Reichardt and Blumtritt* upon the adhesive 
action of iron oxide upon gases, as affording indirect evidence 
in favour of the conclusions at which I have arrived from a 
consideration of the results of my investigation. 
The former chemist found that 100 grm. of ferric hydrate 
recently prepared by precipitation with ammonia, from a 
solution of ferric chloride, yielded, under suitable condi- 
tions, 375 ’54 cc. of a gaseous mixture (0,N and C0 2 ) — that 
the same weight of hydrate previously washed with hot 
water yielded 250‘82 cc, and that 100 grm. of the oxide 
after gentle ignition, w x ere found to retain 40 cc. of gas. 
These results, together with the composition of the gaseous 
mixtures in each case, is set forth below : 
Condition of 
oxide 
Wt. of experimented 
Substce. upon. 
Vol. of 
gaseous 
mixture 
in cc. 
Ratio of 
vol. of 
substance 
in that of gas, 
Per centage composition 
, of gas by vol. 
Wt. of 
co 2 = 
i.e. per 
centage. 
Grms. 
100^ 
| 
fByprecipitating 
Fe.,Cl 6 with 
I NH 4 OH and 
drying in the 
375'54 
i:3 
N O C0 2 
26-29— 3-85— 69-86 
•51 
^ Rll . 
? After washing 
] Avith hot Ava- 
250-82 
i:3-5 
18-9—0-91—80-19. 
•39 
l ter. 
f After gentle 
1 ignition. 
42-69 
1:0-58 
65.32—10-54—24-14 
•02 
These facts not only explain the fact of the retention of 
the fixed alkalis and alkaline earths in the form of carbonates, 
which I have stated to be the case, but compel the inference, 
apart from experimental verification, that the adhesive 
action of ferric hydrate upon saline bodies in solution would 
be equally characteristic. 
* Journ. PraJct. Chem., ii, 440 — 467 (1866). 
