S 6 4 Mr. J. Davy's Account of some Experiments 
the separation of the silex. Calculating from this result, 100 
parts of fluat of ammonia seem to consist of 
76.4 ammonia 
23.6 fluoric acid 
100.0 
Water appears to be a constituent part of this salt. 
It may be rendered neutral by means of a gentle heat, which 
expels the excess of ammonia employed in its formation. In 
its neutral state, it has a strong saline taste, and it readily de- 
liquesces when exposed to the atmosphere. Like the neutral 
carbonats, it is decomposed by heat ; but there is this differ- 
ence between them, part of the pure alkali is expelled instead 
of the acid, and an acid fluat of ammonia is formed. A gentle 
heat only is required for the purpose, that of boiling water is 
nearly sufficient. When the heat is much stronger, the salt 
fuses and passes off in dense fumes of a most peculiar suffoca- 
ting odour. The effects of these fumes, when inhaled, are very 
powerful and disagreeable, and even dangerous, I might ven- 
ture to say, were I to speak from my own experience. In one 
instance, when I inhaled only a small quantity, they produced 
in a few minutes a violent cough and catarrh, and apparent 
accumulation of blood in the neck and head, and symptoms 
altogether not unlike those the attendants of apoplexy, which 
continued for about a quarter of an hour, and then slowly di- 
minished, and gradually disappeared without leaving any per- 
manent bad effect. The fluat of ammonia, when heated in a 
metallic vessel, appears to sublime unaltered. But the result 
is different when the experiment is made in a glass one* Am- 
monia is expelled, the glass is corroded, and subsilicated fluat 
