Phlogiftication of Spirit of Nitre . 14.7 
lefs pure air be imbibed, till the whole come to be of the fame 
quality. It may, however, perhaps follow from the emiffion 
of impure dephlogifticated air, and the imbibing of phlogifti- 
cated aj^r at the fame time, that the former does not confift of 
dephlogifticated and phlogifticated air loofely mixed, but of fame 
intimate union of dephlogifticated air with phlogifton, though 
they may be feparated by a mixture of nitrous air, and other 
proceffes, in the very fame manner as dephlogifticated air may 
be feparated from a loofe mixture of phlogifticated air. 
It is evident from thefe experiments, that a red heat is not 
neceffary to the converfton of nitrous acid into pure air, though 
this procefs, as appeared by my former experiments, produces 
this effedt moft quickly and effedt uaily. 
I cannot help confidering the experiments above recited to he 
favourable to the dodtrine of the phlogifton, and unfavourable 
to that of the decompofition of water, though not decifively 
fo ; for fince the red vapour of fpirit of nitre unqueftionably 
contains the fame principle that has been termed phlogifton, or 
the principal element in the conftitution of inflammable air, 
and according to the antiphlogiftians this is one conftituent part 
of water, they muft fuppofe, that the water in this acid is de- 
compofed by a much more moderate heat than in moft other 
Cafes, In general, I believe, they have thought a red heat to 
be neceffary for this purpofe. It is evident, that theconverfion 
of water into fteam by boiling, or by any heat that can be 
given to it under the ftrongeft prefliire, has no tendency what- 
ever to decompofe it. But if the mere boiling of water in 
nitrous acid could produce this effedt, I do not fee why the fame 
fhould not be the cafe when water alone is boiled. 
I think it will alfb be more difficult to explain the purifica- 
tion of the incumbent atmofpherical air 011 the antiphlogiftic 
Vol. LXXIX, Y than 
