S74 StH On the Analysis of the 
be effected by subjecting it to a long con- 
tinued succession of electrical sparks, or of dis- 
charges froma Leyden jar. This method, 
originally discovered by Dr. Priestley, has 
been employed by the late Count Berthollet, 
by Sir H. Davy, by Mr. Dalton, and by 
myself, with a view to the accurate analysis 
of the gas. The process, however, being one 
into which sources of error may easily be 
introduced, there is not so perfect an agree- 
ment, as might have been wished, among 
the results of different observers. Without en- 
tering into a detail of these discrepancies, 
or a statement of their causes, it may be 
sufficient to observe that the view of the con- 
stitution of ammonia, taken by M.Gay Lussac, 
represents it as consisting of 1 volume of ni- 
trogen and 3 volumes of hydrogen condensed 
into the space of 2 volumes. 
- In order to satisfy myself on a point, the 
determination of which is so essential to a 
just view of the atomic constitution of the 
compounds of nitrogen, I have lately made 
fresh experiments on the decomposition of 
ammonia by electricity, using every precau- 
tion that occurred to me as likely to insure 
the accuracy of the results. The gas was 
collected over recently boiled and dry mer- 
cury, and was transferred for decomposition 
