t 



I 



' 



Analyfis of the Ah\ 



*57 



fires arc continually carrying a large flrcam 

 of heated air out of the rooms up the chim- 

 ney, which dream mult neceiTarily be fup- 

 plicd with equal quantities of irclh air, 

 thro' the doors and windows, or the cranics 



of them. 



And thus many of thofe who have weak 



lungs, but can breath well enough in the 

 freih country air, are greatly incommoded 

 in their breathing, when they come into 

 lame cities where the air is full of fuliginous 

 vapours, arifing from innumerable coal fires, 

 and flenches from filthy lay-ftalls and fewers : 

 And even the moll robult and healthy in 

 changing from a city to a country air, find 

 an exhilarating pleafure, arifing from a more 

 free and kindly infpiration, whereby the 

 lungs being lets loaded with condenfing air 

 and vapours, and thereby the veficles more 

 dilated, with a clearer and more claftick 

 air, a freer courfe is thereby given to the 

 blood, and probably a purer air mixed with 

 it ; and this is one reafon why in the coun- 

 try a ferene dry constitution of the air is 

 more exhilarating than a moift thick air. 



And for the fame reafon, 'tis no wonder, 

 that pcftilential, and other noxious cpide- 



S mical 



>i 









