276 



whose molecular rotation for Sodium-light was about 85 at 20 C., 

 the hydrogen-atom of the NH-group were substituted by a benzoyl- 

 radical, the rotation got the opposite algebraic sign and was 

 simultaneously increased enormously, its value amounting now to 



00 1800 00 5000 5100 5200 53003WO 5500 5600 5?00 5800 MOO 6000 6100 6200 6300 6<tfiO 6500 6600 b?00 6800 6500 7000 flkttfow '/////7s . 



Fig. 171. 

 Rotatory Dispersion of some complex Oxalates of trivalent Metals. 



814; at the same time the hemihedrism of the crystalline forms 

 now appeared clearly manifested. 



From these data it becomes evident, that the connection between 

 molecular dissymmetry and crystallographical hemihedrism, as sup- 



