216 



The explication we gave in our first communication of the magnetic 

 effect, can be transmitted unchanged to the phenomena described 

 above. The different degree of extinction in ex-liquid and ex-solid 

 and the different influence thereupon of a magnetic field, we are 

 inclined to ascribe to the fact that the little parts have a different 

 directability in the ex-liquid state and in the ex-solid state. 



SUMMARY. 



The extinction of p-azoxy-anisol, p-azoxy-phenetal, anisaldazine and 

 p-azoxj-benzoë-acid-aethjiester is examined in its dependence on the 

 temperature. 



It appears that two different liquid-cr3^stalline states exist ("ex-solid" 

 and "ex-liquid") which possess each a different extinction, and which 

 undergo in a different degree the influence of a magnetic field. 



The coefïicient of temperature of the extinction appears to be 

 negative for ultra-red and positive for ultra-violet. 



Utrecht, Februari 1917. Physical Laboratory 



Institute for Theoretical Physics. 



