[ i8 3 ] 
Effay, by an artificial Mixture, to produce the 
like Effedt. It is very well known to every one 
verfcd in Chemical Affairs, that mod Metals emit 
great Quantities of fulphureous Vapours, during 
the. EfFervefcence which they undergo in their So- 
lutions in their relpective Menjirua , or Solvents. 
Of thefe Fumes Iron emits a great Quantity whilft 
it is diflolving in Oil of Vitriol, which are very in- 
flammable, and not eafily to be condens’d. Thefe 
Fumes I collected into a Bladder with the defined 
Succefis, and having produc’d before the Society 
two Bladders of this fictitious Air, at the fame time 
that Sir James Lowther was pleafed to make trial 
of his, they both exhibited the fame Phenomena. 
I fliall here give a more particular Account of 
the Preparation made ufe of, which was as fol- 
lows. 
I took 3 ij of Oil of Vitriol and mixt it with 5 viij 
of common Water, which I put into a Glafis with 
a flat Bottom about ten Inches wide and three 
deep, with a long Neck ; to this I added 3 ij of 
Iron Filings: There inftantly arofe a great Heat, 
with a violent Ebullition, and the Iron was wrought 
upon very faff, with Fumes copioufly exhaling. To 
the End of the Neck of the Glafis I luted a Bladder 
void of Air, the Neck of the Bladder being faften’d 
to a Tobacco-Pipe ; the Fumes arifing from the difi 
folving Metal foon puffed up the Bladder to its full 
Extent, when that being taken away, the Neck 
of it being firft tied clofe with a String, I applied ano- 
ther in the fame manner : Thus you may get as many 
Bladders full as you can, whilft the EfFervefcence lafts. 
T wo of thefe Bladders were tried before the Society, 
O o and 
