Carbonic Acid and Ammonia, 27 
sac indeed suggests an idea that carbonic 
acid gas unites, one measure with 2 of am- 
monia, and in that proportion only, when 
they are mixed together in a tube, introduc- 
ing first a portion of one and then one of the 
the other alternately. Butas this very delicate 
experiment does not appear to have been made 
by him with extraordinary accuracy, it is not 
entitled to much credit. (Mem. d’Arcueil, 
VoL. 2—211),. Besides, what is meant by in- 
troducing the gasses alternately? Is it to be 
understood that if 1 measure of carbonic acid 
is put to 3 measures of ammoniacal gas, and 
no more carbonic acid added, that there will 
not be just 1 measure of ammoniacal gas left 
unabsorbed? If so, what becomes of the 
theory of the combinations of measures in this 
instance? But I shall have occasion to advert 
to this subject more particularly at some other 
time. 
_ Another very important reason for consi- 
dering the combination of 1 atom of acid to 
2 of ammonia as a natural one is, that a.com- 
_ plete mutual decomposition takes place when 
a solution of this character is mixed with a so- 
lution of neutral salt with base of lime. Thus 
an exact subcarbonate of ammonia and sul- 
phate of lime being mixed in due proportion 
and heated to ebullition, sulphate of ammonia 
is formed and carbonate of lime; and the li- 
