358 
DR. A. W. HOFMANN’S RESEARCHES INTO THE 
perfectly in accordance with all the observations recorded, and had been submitted 
to the test of experiment in so many directions, that no doubt was left in my mind 
regarding their correctness. Still, the former inquiry had elicited several facts which 
I was unable to explain by the view which I had taken. These facts J have since 
endeavoured to elucidate by additional experiments ; the results detailed in the fol- 
lowing pages, I am happy to say, are in perfect accordance with my former observa- 
tions, the extension of which has led me, at the same time, to a still more general 
conception of the question. 
After having succeeded in replacing, step by step, one, two or three equivalents of 
hydrogen in ammonia by a corresponding number of compound atoms, the question 
arose whether the agent by which these changes were affected would exert a still 
farther influence upon the last product of the reaction. In order to decide this ques- 
tion by experiment, I submitted two nitrile-bases, diethylaniline and triethylamine, 
to a prolonged action of bromide of ethyl. These experiments, of which a full ac- 
count is given in my preceding memoir (pages 106 and 122), did not lead to per- 
fectly decisive results. It was evident that in these cases a reaction ensued ; even on 
using both the base under examination, and the bromide in the absolutely dry state, 
a gradual change was observed to take place, a small but unmistakeable quantity of 
hydrobromates being invariably formed. No doubt, however, could be entertained 
as to this reaction being altogether different from the preceding stages of the process, 
for instance, the conversion of ammonia into ethylamine, of ethylamine to diethyl- 
amine, &c. ; it was proved, moreover, by careful and frequently-repeated experiment, 
that this process, whatever its nature might be, in no case gave rise to the formation 
of any other volatile bases containing a larger number of replacing radicals than the 
nitrile-base submitted to investigation. 
I have been again studying these reactions during the past year on a much larger 
scale, whereby the experiments were greatly facilitated ; and here I gladly avail my- 
self of an opportunity of expressing my sincere thanks to the Royal Society for the 
kind and encouraging interest they have taken in this inquiry, the new results of 
which are mainly attributable to their liberal and munificent support. 
Action of Bromide and Iodide of Ethyl upon Triethylamine. 
In the paper repeatedly referred to, I have stated that a mixture of an aqueous 
solution of triethylamine and bromide of ethyl, sealed up in a tube, solidified after 
several hours’ ebullition, and that the crystals consisted chiefly of the fibrous hydro- 
bromate of triethylamine, with which however a certain quantity of white opake gra- 
nular crystals invariably was mixed. I have endeavoured to increase the quantity of 
the latter by using both the bromide of ethyl and the triethylamine in the anhydrous 
state. But by thus changing the conditions of the formation, the progress of the 
reaction is retarded in the most remarkable manner, days elapsing before the con- 
