on the Nature of certain Bodies. 
49 
absorbed, I procured by the operation of the moisture of mu- 
riate of lime, nearly eleven cubical inches of volatile alkali, and 
half a cubical inch of inflammable gas ; and the differences, 
there is every reason to believe, were owing to an excess of 
water in the salts, by which some of the gas was absorbed. 
Whenever, in experiments on the fusible substance, it has 
been procured from ammonia saturated with moisture, I have 
always found that more ammonia is generated from it by mere 
heat ; and the general tenour of the experiments incline me 
to believe, that the small quantity, produced in experiments 
performed in vacuo, is owing to the small quantity of mois- 
ture furnished by the hydrogene gas introduced, and that the 
fusible substance, heated out of the presence of moisture, is 
incapable of producing volatile alkali. 
M. M. Gay Lussac and Thenard, it is stated, after having 
obtained three fifths of the ammonia or its elements that had 
disappeared in their experiment, by heating the product; pro- 
cured the remaining two fifths, by adding water to the resi- 
duum, which after this operation was found to be potash. No 
notice is taken of the properties of this residuum, which as 
the details seem to relate to a single experiment, probably was 
not examined ; nor as moisture was present at the beginning of 
their operations could any accurate knowledge of its nature 
have been gained. 
I have made the residuum of the fusible substance after 
it has been exposed to a dull red heat, out of the contact of 
moisture, an object of particular study, and I shall detail its 
general properties. 
It was examined under naphtha, as it is instantly destroyed 
by the contact of air. 
MDCCCIX. 
H 
