150 Mr. Faraday on the mutual action of sulphuric acid 
I thought that, in it, the metallic taste which frequently 
occurred with this acid and its compounds was very decided. 
The action of heat was the same as before. 
Ammonia formed a neutral salt imperfectly crystalline, not 
deliquescent, but drying in the atmosphere. Its taste was 
saline and cooling. It was readily soluble in water and 
alcohol. When heated on platinum foil it fused, blackened, 
burnt with flame, and left a carbonaceous acid sulphate of 
ammonia, which by further heat was entirely dissipated. Its 
general habits were those of ammoniacal salts. When its 
solutions, though previously rendered alkaline, were evapo- 
rated to dryness at common temperatures, and exposed to 
air, the salt became strongly acid to litmus paper. This 
however is a property common to all soluble ammoniacal 
salts, I believe, without exception. 
Baryta. It is easy by rubbing carbonate of baryta with 
solution of the impure acid, to obtain a perfectly neutral 
solution, in which the salt of baryta, containing the acid already 
described, is very nearly pure. There is in all cases an 
undissolved portion, which being washed repeatedly in small 
quantities of hot water, yields to the first portions a salt, 
the same as that in the solution. As the washings proceed, 
it is found, that the salt obtained does not burn with so much 
flame on platina foil, as that at first separated ; and the fifth 
or sixth washing will perhaps separate only a little of a salt, 
which when heated in the air, in small quantities, burns 
without flame in the manner of tinder. Hence it is evident 
that there are two compounds of baryta, which as they are 
both soluble in water, both neutral, and both combustible, 
