on the Nature of certain Bodies. 459 
motive for so doing, is the desire of being assisted or cor- 
rected by the opinions and advice of the learned chemical phi- 
losophers belonging to this illustrious body. In an investiga- 
tion connected with almost all the theoretical arrangements of 
chemistry, and in operations of so much delicacy, it will, I 
conceive, be allowed, that it is scarcely possible to proceed 
with too much caution, or to multiply facts to too great an 
extent. 
The different phenomena presented by the processes of dis- 
tillation in different metallic tubes, may lead to new explana- 
tions of this intricate subject, and though the facts cannot be 
easily accounted for, except on the supposition that nitrogene 
is an oxide, yet till the proportions and weights are distinctly 
ascertained, the inquiry cannot be considered as far advanced, 
for in an experiment, in which the processes are so compli- 
cated and delicate, and in which the data are so numerous, it 
is not easy to be satisfied that every source of error has been 
avoided, and that every circumstance has been examined and 
reasoned upon. 
All conclusions on the action of potassium on ammonia, are 
immediately dependent upon the results of the electrical ana- 
lysis of the volatile alkali. In a letter, which I received in 
the course of the last month from Dr. Henry, that excellent 
chemist, has stated that he conceives I have rather under- 
rated the quantity of nitrogene in ammonia, according to the 
proportions given in the Bakerian Lecture for 1807. This 
notice has induced me to repeat the experiment, under new 
circumstances, and I find not the slightest reason for doubt- 
ing of the entire accuracy of my former results. 
In the new trial, I used mercury which had been recently 
