on the Nature of certain Bodies. 43 
azure tint ; the same series of phenomena, as those before 
described, occur in a continuation of the process, and it is 
finally entirely converted into the dark olive coloured sub- 
stance. 
In this operation, as has been stated by M.M.Gay Lussac 
and Thenard, a gas which gives the same diminution by 
detonation with oxygene, as Irydrogene is evolved, and am- 
monia disappears. 
The proportion of the ammonia which looses its elastic 
form, as I have found by numerous trials, varies according as 
the gas employed contains more or less moisture. 
Thus eight grains of potassium, during its conversion into 
the olive coloured substance, in ammonia saturated with water 
at 63° Fahrenheit, and under a pressure equal to that of 29.8 
inches of mercury, had caused the disappearance of twelve 
cubical inches and a half of ammonia ; but the same quantity of 
metal acted upon under similar circumstances, except that the 
ammonia had been deprived of as much moisture as possible 
by exposure for two days to potash that had been ignited, 
occasioned a disappearance of sixteen cubical inches of the 
volatile alkali. 
Whatever be the degree of moisture of the gas, the quantities 
of inflammable gas generated have always appeared to me to 
be equal for equal quantities of metal. M. M. Gay Lussac 
and Thenard are said to have stated, that the proportions in 
their experiment w r ere the same as would have resulted from 
the action of water upon potassium. In my trials, they have 
been rather less. Thus, in an experiment conducted with 
every possible attention to accuracy of manipulation, eight 
grains of potassium generated, by their operation upon water, 
G 2 
