Analyfis of the Air. it 9 
Experiment XCIL 
Some time in February , the weather very 
cold, I poured upon a quarter of a cubick 
inch of powdered Antimony , a cubick inch 
of compound or double Aqua fortis, in the 
bolthead b> (Fig. 34.) in the firft 20 hours 
it generated about 8 cubick inches of air 3 
after that, the weather being fomewhat 
warmer, it fermented fafter, fo as in two 
or three hours to generate 82 cubick inches 
of air more 5 but the following night being 
yery cold, little was generated : So the next 
morning I poured hot water into the veffei 
x x y which renewed the ferment, fo that it 
generated 4 cubick inches more, in all 13® 
cubick inches, a quantity equal to 5 20 times 
the bulk of the Antimony . 
The fermented rnafs looked like Brim- 
ftone, and when heated over the fire, there 
fubiimed into the neck of the bolthead a 
red fulphur, and below it a yellow, which 
fulphur, as Mr. Boyle obferves, Voh IIL 
p. 272. cannot be obtained by the bare ac- 
tion of fire, without being firft: well digeft- 
ed in oil of Vitriol, or fpirit of Nitre, 
And by comparing the quantity of air ob» 
gained by fermentation in this Experiment* 
with 
