D 108 If now to the filtrate is added much water a yellow product 
is’precipitated. The melting point of the orange-red product is 95 , 
that of the yellow one 80°. This last one proved identical with the 
1 2.4 dinitrodiethylaniline described previously. 
In a quantitative experiment there was obtained from 0.750 gram 
of the substance melting at 59% 0.370 gram of the orange and 
0.358 gram of the yellow product, and from the neutralised mother 
liquors another 0.021 gram of solid matter was obtained. 
If we dissolve a mixture of equal weights of the two nitro¬ 
compounds in boiling alcohol, the compound melting at 59° crystal¬ 
lises on cooling. The curve of the melting points of mixtures 
of both nitro-compounds in different proportions showed undoubtedly 
the existence of a compound formed from equal molecules of the 
said substances. 
The compound melting at 95° is, as will be shown presently, 
1.3.4- dinitrodiethylaniline. It is soluble in most of the organic 
solvents at the boiling heat. If the hot concentrated solution is 
cooled rapidly yellow crystals only are often obtained, whereas on 
cooling slowly orange crystals are generally formed. The yellow 
ones represent the labile ($, the orange ones the stable «-moditication 1 ). 
Occasionally and under definite conditions, a third modification is 
formed which is also yellow, but very unstable, much more so than 
the ^-modification, and which in the dry state passes very slowly 
into the orange one. 
The products formed in the nitration in presence of strong sulphuric 
acid being now known, the progressive change of the reaction was 
investigated more closely. 
In the first place it appeared that in the case of diethylaniline, 
the nitration under the conditions described, that is when 2 mols. 
of nitric acid are used, does also not proceed further than the 
formation of mononitroderivatives. In fact, if to the mixture of 
diethylaniline with sulphuric and nitric acid, is added another mo. 
of diethylaniline, also dissolved in 20 parts of sulphuric acid, and 
the mass poured into iced water, no ^nitro-compounds appear to 
have formed, and we obtain only m. and p. nitrodiethylaniline. 
If, however, we dissolve m. nitrodiethylaniline in 75 times its 
weight of dilute sulphuric acid (1:2) and then add 1 mol. of 
colourless nitric acid, the solution obtained remains clear for days. 
If, however, we add a trace of sodium nitrite, a separation of the 
') Prof. Jaeger has 
examined this compound 
crystallographically, also the 
