570 
in the second list have been found by Hanrzscu; they refer to 
compounds of the same colour. 
MRSA MER. A 
Aedvedinitroam hing: 3) 38 ment tr EN 
2.4, dinitro-methyl-aniline .—. . . . . . , 56,2 
2.4. dinitro-ethykemalme, xn sr peen eee ge 
2.4. dinitro-dimethyl-aniline . . … . . . 61,1 od See, 9.5 
2.4. dinitro-diethyl-aniline . . . . . …… 70,5 98 as 94 
2.4, djnitro-dipropyl-aniline . . « . «°. 80,8) “> 81,1) ~ 
The values found by me are somewhat smaller than those found 
by Hantzscu. He used chloroform as a solvent, I used pyridine. The 
differences between the homologous members (indicated by A) are 
alike in the two series, if we take into consideration that the expe- 
rimental errors beeome considerable in consequence of the high 
molecular weights. It is to be remarked that the molecular refrac- 
tions of the dimethyl- and the ethyl-compound are the same. 
We shall now pass on to the comparison of the other determi- 
nations by HaNrzscH with mine, the latter being placed in the 
first row. 
M:R. A M-R. A 
3.4. dinitro-dimethyl-aniline (yellow) . . . 62,8 103 61,5 78 
. 3 € > > . fc 
oe … . diethyl-aniline (orange)... ». 73,1 69.3 
2.4.6. trinitro-dimethyl-aniline (y.) . u. . 65,71. . 7631] —— 
pr aE Ys bic ai tye de eee 
NN »  diethyl-aniline (o.) 63,0 96 van 
is > dipropytantine (opte ar. 64/6)” 
The results are very different for these homologues, which have 
not got the same colour. This is easy to explain for the 3.4. dinitro- 
dimethyl-aniline, because HartzscH did not use this substance, but 
the 2.4. dinitro-mono-methyl-aniline. 
Except the already mentioned nitro-compounds I have still exa- 
mined other homologues of the same as well as of different colours. 
For convenience’ sake, I unite them all in two groups. First those 
having the same colour (yellow, orange, or red) and under them, 
those differing in colour. 
M.-Ro MBZ 
m-nitro-dimethyl-and-diethyl-aniline (o.). . . 48,5 and 58,2 Ov 
p-nitro-dimethyl-and-diethyl-aniline (y.) . …. . 56,6 „ 67,2 10,6 
2.4. dinitro-dimethyl-and-diethyl-aniline (y.). …. 61,1 ,, 70,5 9,4 
3.6. dinitro-dimethyl-and-diethyl-aniline Jaa S68) oei B 
