AnaJyJis of the Air. 2 1 p 



Experiment XCII. 



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 thefirft2o hours 

 it generated about 8 cubick inches of air ; 

 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 very 

 cold, little was generated : So the next morn- 

 ing I poured hot water into the veffel x x> 

 which renewed the ferment, fo that it gene- 

 rated 4 cubick inches more, in all 130 cubick 

 inches, a quantity equal to 520 times the 

 bulk of the Antimony. 



The fermented mafs looked like Brim- 

 flone, and when heated over the fire, there 

 fublimed into the neck of ihe bolthead a red 

 fulphur, and below it a yellow; which ful-. 

 phur, as Mr. Boyle obferves, Vol. III. p. 272, 

 cannot be obtained by the bare a&ion of fire, 

 without being fir ft well digefted in oil of 

 Vitriol, or fpirit of Nitre. And by com- 

 paring the quantity of air obtained by fermen- 

 tation in this Experiment, with the quantity 



obtained 



