﻿8.— Diffusion of carbonic acid. 



PER 



CARBONIC ACID 



S 





CCNT .03 



n 



IN COUNTRY 

 AIR 



04 .07 



D D 



INTOWN INCLOSE 

 AIR ROOMS 



IN 



THE 



BREATH 







OXYGEN 









NITROGEN 







-Proportion of gases in atmospheric air and breath. 



The Air of Towns. 



