INCOME AND OUTGO 



329 



The air which is making the circuit outside the chamber 

 is first driven through a jar containing sulphuric acid. 

 This removes from it all moisture. The acid is gradu- 

 ally diluted by the addition of water brought from the 



chamber and gains weight in proportion as this water 

 is added to it. The weight of the container is determined 

 at the beginning of each experiment and by weighing 

 it again at the close the amount of water swept out by 

 the air current can be estimated. This water has come 



