26 Eaperiments and Observationson 
they had lost less or more of the ammonia 
according to circumstances pointed out 
above. . 
That this idea is correct there seems little 
doubt from the following experiment. 
I took a sample of salt that was about half 
carbonate and half subcarbonate, and having 
put it into a tube, I sublimed a portion of it 
by a gentle heat into a phial. The sublimed 
portion was immediately dissolved in water, 
and then analysed in the mode above men- 
tioned. It proved to bea true subcarbonate, 
or a compound of 1 atom of acid and 2 of 
base, as [had apprehended. We may be as- 
sured that such a compound is formed by na- 
ture from the experiments on the combinations 
of these two elements in an elastic form. Dr. 
Priestley ascertained that 1 measure of car- 
bonic acid gas absorbed nearly 2 measures of 
ammoniacal gas ( Vox 2. 387, abr.), and when 
the ammoniacal gas was greatly im excess, 
nearly 3 measures. Judging from the speci- 
fic gravities of the two gasses, 1 measure of 
carbonic acid should take + of a measure of 
ammoniacal gas to form carbonate of ammo- 
nia, 4 of a measure to form subcarbonate, 
and * to form subtricarbonate (supposing 
such a compound to exist which we shall shew 
presently is highly probable). M. Gay -Lus- 
