146. Mr. Cavenpisu’s Experiments on Air, 
of the acid in the nitre 1s turned into, phlogifticated air, by ab ; 
forbing phlogifton from.the watery part. . 
From what has been faid it appears, that there is a . confider= 
able difference i in the manner m which the acid acts in the pro-= 
duGtion, of dephlogifticated air from red precipitate and from 
nitre; in the former cafe the acid comes over firft, leaving the 
remaining fubftance deprived of part of its phlogifton ; 1n the. 
latter the dephlogifticated air comes firft, leaving the acid loaded , 
with the phlogifton of the water from which it was formed. 
On diftiling a mixture of quickfilver and oil of vitriol to 
drynels, part of the acid.comes over, loaded with phlogifton, . 
in the form of volatile fulphureous acid and vitriolic acid air; fo 
that the remaining white mafs may be confidered as confifting 
of quickfilver deprived of its phlogifton, and united to a certain | 
proportion of acid and water, or of plain quickfilver united to 
a certain proportion of acid and dephlogifticated air. Accord- 
ingly on urging this white mafs with a more violent heat, the . 
dephlogifticated air comes over, and at the fame time part of 
the quickfilver rifes in its metallic form, and alfo part of the 
white mafs, united in all probability to a greater proportion of 
acid than before, fublimes; fo that the rationale of the pro= 
duction of dephlogifticated air from turbith mineral, and from, . 
red precipitate, are nearly fimilar, 
True turbith mineral confifts of the abovementioned white - 
mafs, well, wafhed with water, by which means it acquires a 
yellow colour, and contains much lefs acid than the unwafhed 
mafs. Accordingly it feems likely, that on expofing this, to 
heat, lefs of it fhould fublime without being decom pounded, and ~ 
confequently that more dephlogifticated air fhould be. procured 
from it: than from the unwathed mafs, 
This. 
