(18°) 
EXPERIMENTS AND OBSERVATIONS 
ON THE 
COMBINATIONS 
OF 
CARBONIC ACID AND ' AMMONIA: 
BY JOHN DALTON. 
, (Read March 19, 1813.) 
= POE 
THE compounds of carbonic acid and am- 
monia in various shapes have been known to 
Chemists:and Physicians for more than a cen- 
tury; but the nature’and constitution of these 
compounds were comparatively little known 
till. Dr. Black. discovered some of the cha- 
racteristic properties, of carbonic acid; and 
soon after Dr. Priestley discovered:several of 
those of ammonia. These two elements be- 
ing never exhibited alone, except in the state 
of elastic fluids, it is not to be expected that 
any \precise information can be obtained re- 
specting them till the! era of: pneumatic che- 
mistry, which may bé''said’in some’ sense*to 
have commenced with the two distinguished 
chemists above mentioned. 
In the progress of science, Lavoisier more 
particularly pointed out the nature of carbo- 
