274 
Mr. Read's Experiments and Observations , &c. 
fourteen revolutions. As I perceived no smell in this close hot- 
house, I am inclined to attribute the negative electric state of 
the vapour to the heat of the fire and vigour of the plants, 
which possibly may absorb the fluid faster than it could get in 
through theffioor, which is rendered very dry by flues that lie 
on three sides of it. 
Without even attempting to consider in this place how far 
the influence of electricity is concerned in all sorts of vitiated 
air, it will be sufficient to remark, as it clearly follows from the 
preceding experiments, that air infected with animal respira- 
tion, or vegetable putrefaction, is always electrified negatively, 
when at the same time the surrounding atmosphere is electri- 
fied positively. 
