PLATE XXXIII 



Fig. I. — Special container for sulphuric acid to remove water vapor from air passing 

 through it. At the right is a stopper with the entrance and exit tubes, as described 

 on p. 306. 



Fig. 2. — A small absorber train for removing water vapor and carbon dioxid from 

 sample of residual air. An empty acid bottle is shown at the left. 



