180 Dr . Beddoes on fame appearances attending 
procefs ; a fa£t which perfectly coincides with the preceding 
obfervations, fince that fpecies contains lefs plumbago, or in 
other words leis matter fit to produce elaftic fluids. 
Ill order to prove the extrication of fixed air during the 
fermentation of the metal, I once thought of introducing lime- 
water in an iron veflel within the body of the furnace; but 
when 1 confidered that the fire-place was not divided by any 
partition from the body of the furnace, and that the whole 
building was full of burned air, I omitted the experiment from 
a perfuafion that, even if the lime-water fhouid become turbid, 
the fixed air might come from another fource. 
I was not unmindful of the fulphur which exifts, as I have 
reafon to believe, in every form of iron manufaftured with 
coaks. I cannot, however, afcribe any of the effects I ob- 
ferved to its prefence. There can be little doubt, that fome 
portion was perpetually extricated with the inflammable air 
during the whole procefs ; for on difl'olving pieces of the 
ftamped, or rather the rolled iron in weak muriatic acid, filver 
held in the extricated air was tarnilhed as much and as foon as 
by air from fpecimens taken out of the furnace at different 
times during the procefs. I could not but conclude, that the 
tarnifliing matter came from the iron, when I found the air 
from a folution of zinc in the fame acid, incapable of pro^ 
ducing the colour upon filver. The appearance, the want 
of a martial aftringent tafle, and the diflfolving action of 
cauftic alkali, led me to conclude, that the colour in each expe- 
riment with iron was derived from fulphur. 
I leave it to the adherents of phlogifton to accommodate 
thefe phenomena to their doftrine ; confidering it, for my 
own part, as fuperfluous to bellow any further attention upon a- 
2 fyftem 
