238 Intelligence and Miscellaneous Articles. 



Temperature. 



Resistance 



o 

 15 



1200 



35 



128-6 



53 



137-4 



The coefficient K, being- calculated by the formula R; = R (c-f-Kj), 

 gives 0*0038, which is within the limits found for this coefficient in 

 the case of most metals. — Comptes Rendus, March 31, 1863. 



ON THE MAGNETICAL DEPORTMENT OF SOME CYANOGEN COM- 

 POUNDS OF IRON, NICKEL, AND COBALT. BY DR. J. WIE- 

 SENER. 



The following conclusions have been arrived at after a lengthened 

 investigation of this subject : — ■ 



1. Those cyanogen compounds of iron, nickel, and cobalt in 

 which these metals are present as in an haloid, or ordinary salt, are 

 paramagnetic. 



2. Those compounds in which the cyanogen appears to form with 

 either of the three metals a compound radical (in which therefore 

 iron, nickel, or cobalt cannot be directly detected) may either be 

 paramagnetic or diamagnetic. 



3. The compounds of the general formula Ni Cy. 2 Me are, as far 

 as the present investigations have extended, diamagnetic. 



4. The compounds constituted like hydroferrocyanic acid, Fe Cy 3 

 H H, are diamagnetic if the hydrogen is replaced by diamagnetic 

 metals, but paramagnetic if by magnetic metals. 



5. The cobalticyanide compounds show the same deportment. 



6. The compounds analogous to hydroferricyanic acid are without 

 exception paramagnetic. — Sitzungsbericht der Wiener Academie, vol. 

 xlvi. p. 175. 



EESEARCHES ON THE OPTICAL PROPERTIES DEVELOPED IN 

 TRANSPARENT BODIES BY THE ACTION OF MAGNETISM. BY 

 M. VERDET. 



I have the honour to submit to the Academy the result of a 

 series of experiments on the relation existing between the magnetic 

 rotation of the plane of polarization of a ray of homogeneous light, 

 and its wave-length. An experiment by M. Edmond Becquerel, 

 which consisted in compensating the action of a piece of heavy glass 

 placed between the branches of an electromagnet by the action of a 

 column of solution of sugar, seemed to show that, for this substance 

 at least, the law of rotations differed little from the law of the 

 inverse ratio of the square of the lengths of undulation. More 

 recent researches by M. Wiedemann led to the conclusion, 1st, that 

 the law did not apply to sulphide of carbon, and is therefore 

 wanting in generality ; 2nd, that when an active substance, such as 

 essence of lemon or oil of turpentine, was submitted to the magnetic 

 influence, there was, for each colour, proportionality between the 



