Smithsonian Report, 1895. 



Plate IV. 



8.— Diffusion of carbonic acid. 



PCR 



CARBONIC ACID 



S 





□ 



IN COUNTRY 

 AIR 



04 .07 

 □ □ 



INTOWN INCLOSE 

 AIR ROOMS 



IN 



THE 



BREATH 







OXYGEN 









NITROGEN 







9. — Proportion of gases in atmospheric air and breath. 



The Air of Towns. 



