368 Mr. J. Davy’s Account of some Experiments 
Sect. IV. On the Combinations of fluoboracic acid Gas , and 
ammoniacal Gas. 
M. Gay Lussac has combined fluoboracic acid gas with 
ammonia. He states, that equal volumes of the two gasses 
condense each other.* This I have found to be the case, and 
I have also found that fluoboracic acid gas condenses twice, 
and even three times its volume of the volatile alkali. The 
compound observed by M. Gay Lussac is solid, white, and 
opaque, like the ammoniacal salts. The combinations I have 
obtained are liquid, transparent, and colourless, like water, 
though they are entirely free from this fluid. They were 
made by the direct union of the two gasses. 5 cubic inches of 
ammoniacal gas were added to the same volume of the fluo- 
boracic gas contained in a small jar over dry mercury. There 
was a complete condensation of both, and the solid salt was 
the result. 5 cubic inches more of ammonia were introduced. 
The whole was quickly absorbed, and the solid salt was con- 
verted into the transparent fluid. 5 cubic inches more were 
added, which too were slowly absorbed, but without any 
change of form. 
The solid salt volatilizes in close vessels unaltered, on the 
application of a gentle heat. 
Both fluid compounds, when heated, are rendered solid, 
from the expulsion of part of the ammonia. Exposure to the 
air is attended with the same change, and the same effect is 
produced by the muriatic and carbonic acid gasses. 
Knowing the volumes of the acid, and alkaline gasses which 
* Vide Mem. d’Arcueil, Tom. II. 
