MISCELLANY. 
34? 
quantity of the bleaching hypochlorite of potassa is produced. In the 
new process described above, there is no reason to believe that the carbo- 
nate of potassa is decomposed by the dry hydrate of lime till the chlorine 
is presented to the mixture; then, while the lime attracts the carbonic 
acid, the chlorine acts simultaneously upon the potassa, and the carbonate 
of potassa is thus readily decomposed. The same principle of calling in 
a secondary agency to promote combination, may be taken advantage of 
in many other cases. Thus hydrate of lime, dry or slightly damped, 
ceases to absorb sulphuretted hydrogen long before it is saturated with that 
gas ; but, if mixed with an equivalent of hydrated sulphate of soda, the 
absorption takes place with greatly increased avidity, and goes on until 
two equivalents of sulphuretted hydrogen are taken up for one equivalent 
of lime. But here, with the assistance of sulphuretted hydrogen, the 
hydrate of lime decomposes the sulphate of soda, sulphate of lime being 
formed, while caustic soda combines with the sulphuretted hydrogen. 
Lond. , Edin. and Dub. Phil, Mag. 
Action of Acids on Sulphate of Iron. By M. Callond, (d'Ancey.) — I 
have made an observation which appears to me to be new, which, by the 
advice of my colleagues, I make known to chemists, to examine more 
particularly the phenomena, and produce, if possible, an explanation. 
The proto-sulphate of iron, placed in contact in the cold with strong 
sulphuric acid, assumes a more or less intensely red colour. I have ob- 
served that on adding a small quantity of water, and agitating slightly, so 
as to disturb the red colour, this presents the fine appearance of the vapour 
of iodine. 
Sulphuric acid, which does not produce this effect, either from its want 
of strength or from the presence of organic matter, may be caused to ac- 
quire this remarkable property by being boiled with a few drops of nitric 
acid for a length of time sufficient to drive off the nitric oxide formed. 
If the sulphuric acid produces the new character with the salt in only 
an insensible or slight degree, one drop of nitric acid will develope it ra- 
pidly ; and when the glass is long and narrow, a variety of violet red 
zones will be observed. That portion which is not in contact offers no 
colour. When mixed the whole colour disappears. When water is 
added to the most intensely red product, the colour likewise disappears. 
I do not believe that this is in consequence of oxidation. On the first 
contact with the acid, the surface of the salt shoots out small crystals 
and becomes white, probably passing to the anhydrous state. If the 
sulphate becomes oxidized, the liquid presents more or less of a red 
colour. 
Nitric acids alone does not produce upon the salts any variation but 
what is known. — Jour, de Chtm. Med. 
