Pike aa 
Be 
* 
114 Scientific Intelligence. 
The nitroprussids are very liable to change, and hence the determi- 
nation of their true formula isa matter of some difficulty. The indus- 
trious and accurate author records over one hundred analyses of the salts 
on the products of their Jextepoeiiins The analyses most trust wor- 
thy agree very nearly in assigning a composition which aside from its 
apparent complexity, seemed so improbable, that they have been repeat- 
ed under every variety of circumstance with the view of obtaining simple 
results, which have however obstinately refused to show themselves. 
e formula thus obtained is Fe,C,,N,,0,R,. The author would 
have pate the ratio Fe, to o.. , but,as we have said, the analyses 
would not allow of it. Various conjectures are given as to the rationale 
of this curious composition, — which point another paper is promised. 
We are indebted to Gerhardt for a series of formulas by which under 
his genus of Polycyanid, we can include without difficulty all the vari- 
ous compounds which have caused so much trouble to chemists, and 
to explain _— at least oe hypothetical lege are generally re- 
quired. Let stand for iron with two s its usual wen .» as in 
peroxyd, Sbechiocid; &c., and we have the Follewinig formulas 
errocyanid, Cio (Fe, R,) Ne 
Ferridcyanid, re (Fe, R,)N, 
Turnbull’s blue, C,,(Fef,Fe,) Nz 
By similar experiments we can debuts the composition of Everitt’s 
salt, the complex ferrocyanids and the other varieties of Prussian blue. 
By doubling the equiv. to avoid fractions, we have the nitroprussids as 
ollows : 
Nitroprussids, C,, (Fe Fe? R,)N,.-+3NO. 
Fe and Fef, or Fe'? being together equal to Fe,, as given in the 
analysis. The only difficulty is in the relation of 3NO. This from 
its somewhat basic character may be superadded to the polycyanids as 
NH, is to the ordinary cyanids. Possibly there may be some connection 
between this and the absorbtion of y protosalts of iron. Xt any 
rate the formula expresses a relation to known compounds, and accounts 
acinntgiee well for some phenomena in the decomposition sf io bah 
. C. Scu 
anew property of Carbonic Oxyd ; by F. eee “(Comptes 
Rendus, April, 1850.)—In absorbing oxygen from a gaseous m mixture 
the ammoniacal subchlorid of copper, it was noticed that a large 
bo 
quantity of carbonic oxyd was also dissolved. The same reagent w 
protected from the action of the air was found to absorb the gas readily 
vd at retain its property of becoming blue on exposure to the = or 
-. 
The solution of subchlorid copper in muriatic acid possesses “ihe 
same properties, absorbing the gas as readily as solution of caustic 
potash absorbs carbonic acid. It is remarkable - after saturation the 
subchlorid is = tam by dilution with wate 
All attempts to procure a solid compound of oe gas and salt failed. 
The quote aiken up was one equivalent of CO for one equivalent t Cu. 
yellow recl ipitate, : 
he air. 
15. On the Aérometric Balance, an instrument 
Density of the air in which it is placed; by Pre 
2 
