1 8 Dr. Priestley’s Experiments 
air. It is evident, therefore, that the iron had imbibed pure 
water only. Had the iron imbibed dephlogifticated air from 
the water, and not water itfelf, there feems to be no reafon 
why fixed air fhould not be found in this, as well as in the 
exactly fimilar procefs with minium and precipitate per fe. 
Alfo, it can never be fuppofed, that the addition which iron 
gains, of one-third of its weight, is from air contained in 
fleam, if it could be proved to contain any ; becaufe, if there 
be a fufficient quantity of iron, the whole of the water will 
be imbibed ; fo that, on this hypothecs, water muft be nothing 
but dephlogifticated air condenfed. 
There is, I acknowledge, a great difficulty in explaining the 
experiment of iron firft imbibing water, and parting with phlo- 
giflon, and again parting with its water, and imbibing phlo- 
giflon, in circumftances of heat fo nearly fimilar as thofe which 
I have defcribed. It feems as if the affinity of iron to water and 
to phlogifton was each, in their turns, flronger than the other. 
To this I can only fay, that the whole dodtrine of affinities, 
as far as it is true, is founded on fadls ; and thefe are clearly 
fuch as I have reprefented ; and that a difference of circum- 
ftances, which is not apparent at prefent, may become fo 
when we fhall have given fufficient attention to them. 
In order to fatisfy myfelf whether any thing befides water 
was expelled from finery cinder by heat, I went through fimi- 
lar proceffes with this fubflance and majjicot , from which all 
air had been previoufly expelled ; and after reviving both of 
them in inflammable air, I found the refults, in all refpedts, 
the very fame. The refiduums of the inflammable air were 
equally free from fixed air ; and when they were fired with 
equal quantities of dephlogifticated air, the diminutions of 
bulk 
