571 
Me NEER, A 
2 nitro-dimethyl-and-diethyl-toluidine (0.) … . 53,1 and 62,1 , 9,0 
2.5. dinitro-dimethyl-and-diethyl-toluidine (r.) . 61,4 ,, 69,2 | 7,8 
3.4. dinitro-dimethyl- (y.) and-diethyl-aniline (0.) 62,8 ,, 73,1 10,3 
2.4.6. trinitro-dimethy I- (v.) and-diethiyl-aniline(o.) 65,7 7 
3.4.6. trinitro-dimethyl- (0.) and: diethyl-aniline (y.) 68,2 
+) 
5 77,5 | 9,8 
From these determinations it is clear that both with the homo- 
logues having the same colour and with those having different colours, 
the difference of the molecular refractions is sometimes far removed 
from that calculated by Brünr (4,6 per CH, group). 
Therefore in my opinion the refractometrie determinations do not 
make me assume from the difference in colour of homologues that 
there is a difference in their subsidiary valencies. 
This consideration caused me to carry on my research of mole- 
cular refractions in quite another direction. 
Some years ago Hanrzscuy ') had called attention to the fact that 
with the nitro- and aldehydephenols, as well as with their salts and 
also with the nitroanilines the orthocompounds have smaller mole- 
cular-refraction than the para ones. 
Now I intended not only to test a number of mononitroanilines 
by the rule given by Hanrzscu, but also to seek among several 
aromatic nitro-compounds relations between the value of the molecular 
refraction, and the position of the groups united with the benzene- 
nucleus. 
If really these relations existed, then for nitro-compounds the 
refractometer might be used as a welcome instrument to detine their 
constitution. 
The relation as stated by Hantzscu between the value of the mole- 
cular refraction and the position of the nitro-group I could observe 
with a number of compounds. 
M-R. A M-R 4 
DEREPORARDE en ge 8 3,5 | len 3.40 
EER Ans, alo tn a | 41,96 
BEMINRNURS Cr ee BBI | 
The numbers I found in pyridine-solution are somewhat lower 
than those found by Hanrzscu, who dissolved in acetone ; however 
the differences are the same. 
1) B. 43, 100 and 1656 (1910). 
