( 438 ) 
nitrie acid. The three halogen atoms and the three nitro-groups 
then always jointly occupy the three free meta-places and, therefore, 
take up in regard to NH, and OH the ortho- and para-positions, but 
never the two remaining meta-places. It is a remarkable fact that 
these substitutions take place so much more readily than they do 
in the case of other benzene derivatives. 
Some time ago LANGER!) has considerably supplemented some 
existing observations by a systematic investigation of aniline-deri- 
vatives and demonstrated that even if one or both meta-places are 
occupied in regard to NH, the substitution of the three remaining 
places by halogen proceeds quite as readily as in the case of free 
aniline. 
No similar systematic investigation has been made in the case of 
phenol; on consulting the literature we find that a number of obser- 
vations made at the halogenation and nitration of some substituted 
phenols point to the existence of a similar regularity. 
In order to obtain additional confirmatory evidence in the case 
of the derivatives of aniline and phenol Dr. BLANKsMA has in the 
first place investigated the behaviour of symmetric dinitro-aniline 
towards halogens. Trichloro- and tribromodinitro-analine were very 
readily formed : 
NH, NH, 
os 
4 ) Cl 
| 
\ 
BS 
fa | 
NO, be je NO, SS se NO, 
Cl 
It further appeared that symmetric dinitrophenol was readily con- 
verted by bromine water into the already known but differently 
obtained tribromodinitrophenol; in the case of m-nitrophenol the 
conversion into a tribromoderivative had already been proved. 
Dr. BLANKSMA secondly put the question how nitric acid will 
behave towards nitrated meta-derivatives of aniline and phenol. It 
is known that by direct nitration no more than three nitro-groups 
can be introduced into benzene and its derivatives; even picric acid 
Cl 
1) B. 15. 1061. 1328. 
