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particle of iron diffolved by an acid, unlefs the metal 
was fupported by fome other menftmum. 
My endeavours, therefore, to detect this folvent, 
by experiments, are what I now beg leave to lay be- 
fore you, in the order I made them. 
Experiment I. 
A wide-mouthed bottle, containing half a pint of 
diftilled water and fixty grains of fteel-filings, was 
fufpended forty-eight hours over fome diftillers me- 
lalies, in brilk fermentation j fo as to receive the fixed 
air efcaping from the fermenting liquor ; the furface 
of which was ten inches below the mouth of the 
bottle. Immediately after its removal, the clear water 
was decanted from the filings and ochrous fediment. 
This liquor had a brilk and ferruginous tafte, with 
a flavour of the melaffes. An infufion of galls, or 
green tea, foon changed part of it to a colour like 
ink. The remainder, being expofed to the open air, 
prefently became turbid, threw up a party-coloured 
pellicle, and depofited a ycllowifli fediment. 
The water now retained but very little power of 
tinging with galls 3 and in a few days loft this pro- 
perty entirely. 
Experiment II. 
Fourteen ounces of coarfe fugar, diflblved in feven 
pints of water, were mixed with half a pint of yeaft, 
in a bottle capable of holding more than twice the 
above quantity. One end of a bent tube was luted 
into this veflel, fo that no air might efcape but through 
