1099 
The difference in molecular-refraction of the two coloured dinitro- 
dimethyl-p-toluidines nearly disappeared after substitution of a NO- 
eroup for a CH,-group in consequence thereof almost colourless 
nitrosamines are formed. 
Moreover the molecular-refractions of the nitro-toluidines prove 
to be considerably raised. That this is really the case, becomes more 
evident, if we pay attention to the fact that the molecular-refraction 
is obtained by multiplication of the specifie refraction with the 
molecular weight, the latter being greater with the nitrosamines than 
with the dimethyl-compounds. 
Though the difference in molecular-refractions of nitro-toluidines 
lies far above the experimental errors, it was not exceedingly high. 
Therefore T thought it of some interest to determine the molecular- 
refractions of nitrosamines, derived from isomeric nitro-compounds 
which showed a great difference in molecular-refraction. 
These nitro-compounds were chosen out of some dinitro-dimethyl- 
(diethyl) anilines mentioned already in a former communication. 
Spec. Refr. M.-R. A 
3.4-dinitro-dimethy l-aniline 0,2975 | 62,8 
Bo NS 6,2693 | 56,8 | ° 
3.4-dinitro-diethy l-aniline 0,3060 | 73,1 
Ene 0,2730 | 65,3 | °° 
The refractometric values of the respective nitrosamines appear to 
be as follows: 
Spec. Refr. M.-R. A 
3.4-dinitro-phenyl-methyl-nitrosamine') 0,2444 | 55,2 
Bogs uc y 7 F 1) 0,2337 | 52,8) 2+ 
3.4-dinitro-pheny l-ethyl-nitrosamine 0,2483 | 59,6 9 
BE 3 il 0,2380 |57,2| 2-4 
The difference in molecular-refractions of the isomeric nitrosamines 
is, just as in the above mentioned case, much smaller than that of 
the dimethyl-compounds. The molecular-refractions of the dinitro- 
dimethyl-anilines are much more raised than those of the dinitro- 
dimethyl-toluidines. Here, too, this rise is prominent with the specific 
refractions. The specifie refractions of the nitrosamines are between 
0,2483 and 0,2337 and those of the dinitro-dialkyl-anilines between 
0.3060 and 0.2693. In relation with these high values of the specific 
refractions of nitrated dialkyl-anilines and the low, little differing 
values of the nitrosamines, the refractometer (according to my opinion) 
1) The description of these compounds, and of some others will soon appear. 
