16 Ur. Priestley’s Experiments 
have united with the pure air from the turbith mineral, and 
have made vitriolic acid ; but no vitriolic acid air would have 
been produced. 
That vitriolic acid air contains the fame inflammable prin- 
ciple with inflammable air is evident from the quantity of 
vitriolic acid air which I produced by reviving copper from blue 
vitriol in inflammable air. See my Experiments, vol. VI. p. 
15. Mr. Kirwan alfo produced this air from fulphur and red 
precipitate. See his Treatife on Phlogifton, p. 29. 
When I ufed a fmall quantity of fulphur in proportion to 
the turbith mineral, the firft produce was vitriolic acid air, 
and afterwards dephlogifticated air, from the turbith mineral 
alone, the effect of the fulphur having been exhaufted. 
According to the antiphlogiftic theory, phofphorus , as well as 
fulphur, is a Ample fubftance ; and when it is ignited imbibes 
pure air, and thereby becomes the phofphoric acid, without 
parting with any thing. But I find, that after the accenfion 
of it in dephlogifticated air, there is a confiderable quantity of 
fixed air in the refiduum ; and this fixed air could only be 
formed by the union of the dephlogifticated air in the veflel 
with the phlogifton contained in the phofphorus. Mr. Kir- 
wan had a fimilar refult from phofphorus confined in atmo- 
Ipheric air. As it is not pretended, that there is any plumbago in 
phofphorus, this experiment is not liable to the objection that 
has been made to thofe in which inflammable air from iron 
was made ufe of. 
It will be expected, that in this reply to the objections that 
have been made to my experiments eftablilhing the doctrine of 
phlogifton, I fhould confider what has been alledged by MeflT. 
Lavoisier, Berthollet, and de Fourcroy, in favour of 
their new fyftem, in their Report on the fubject of the new 
chemical 
