106 
DR. A. W. HOFMANN’S RESEARCHES REGARDING THE 
I have not examined any other of the salts of diethylaniline : their deportment re- 
sembles in every respect that of the ethylaniline-salts. 
Action of Bromide of Ethyl on Diethylaniline. 
If we assume that the series of bases, aniline, ethylaniline and diethylaniline, arise 
from the gradual elimination of the three equivalents of hydrogen in ammonia, and 
their substitution by 1 equivalent of phenyl and 2 equivalents of ethyl, it is difficult 
to imagine that bromide of ethyl should have any farther action on diethylaniline, 
this compound ammonia containing, according to this view, no longer any replaceable 
hydrogen. However, it would have been deserting the path of inductive research, if 
this point had been left unestablished by rigorous experiments. 
For this purpose diethylaniline was left in contact with bromide of ethyl for nearly 
a month. After the lapse of this time the mixture had undergone no change in its 
appearance. On treating however a portion with water, it was found that a small 
quantity of hydrobromate dissolved, from which on addition of potassa an oily base 
was separated. The quantity obtained in this manner from nearly two ounces of the 
united liquids being insufficient for a determination, I subjected a similar mixture, 
in a sealed tube, for several days to the temperature of boiling water. I was 
surprised to find that a yellow layer began to separate at the lower extremity of the 
tube, which increased gradually to a fifth of the liquid column. When allowed to 
cool, this layer solidified into a crystalline mass. On opening the tube, it was found 
that there was no pressure from within, except that exerted by the elasticity of bro- 
mide of ethyl. After separation of the excess of the bromide by distillation in the 
water-bath, water added to the viscid residue dissolved the crystals, while an oil 
floated upon the surface which was found to be entirely basic : it was separated by 
a distillation at a higher temperature, when it was carried over with the vapour of 
the water. The remaining liquid in the retort was found to be a solution of a hydro- 
bromate. It was decomposed with potassa, and the liberated base separated from the 
bromide of potassium by distillation. The two basic oils obtained in this manner, 
when dissolved in hydrochloric acid and precipitated by bichloride of platinum, gave 
rise to the formation of two splendid platinum-salts. These salts left on ignition the 
following percentage of platinum ; I. being the oil which had not been in combina- 
tion ; II. the base which had been separated from the hydrobromate. 
I. 0-5626 grm. of platinum-salt left 0*1559 grin, of platinum. 
II. 0*5384 grm. of platinum-salt left 0*1495 grm. of platinum. 
Experimental percentage of platinum. Theoretical percentage in diethyl- 
f ciniline-platinum-salt. 
I. II. 
2770 2776 2778. 
These experiments prove that the basic oil obtained on direct distillation, or by 
distilling after treatment with potassa, had not assimilated a farther equivalent of 
