S. Webber on Ventilation. 377 
"gravity at the same temperature. 
; will cease, and mechanical compulsion will be needed to 
external air into the room. But if the room had within 
fa permanent source of caloric or a permanent absorbent of 
currents. would be equally permanent, varying in force 
additional quantity of carbonic acid gas, and depriving it of a 
quantity of its oxygen. Now carbonic acid gas is of a deci- 
les. 
If we could suppose a close room filled with carbonic acid gas 
would soon begin to take place by the existence of a new,princi- 
ple of action. Caloric has a tendency to diffuse itself equably 
through all bodies in, contact with each other, so as to bring them 
all to the same sensible temperature as measured by the ther- 
mometer, In consequence of this, some of the caloric combined 
With the-carbonic acid would leave it, to combine with the colder 
floor of the and part through the ) the window. 
to the ground. The place of whateve sank downward mae 
