ON THE AIR AND RAIN OF MANCHESTER. 



211 



sphere to allow us to see them, there is therefore any 

 greater proof that the air had these impurities in them. It 

 was well known before. The action on the system for so 

 many years, producing almost a different race of men, is a 

 stronger proof of a chemical action than any thing done in a 

 bottle. This difference of feeling which we have in different 

 atmospheres, may be said to be perceived by our chemical 

 senses, as the effect is produced by decomposition in the 

 S3''stem, and not by physical contact, otherwise we should feel 

 the pain on the skin, or at furthest in the lungs. After 

 breathing certain gases, either sulphuretted hydrogen, sul- 

 phuric acid, nitrous gases, muriatic acid, or chlorine, a certain 

 lassitude and an inclination towards anxiety is felt; certain 

 decompositions have been put in motion, and certain others 

 have been arrested, which produce this result in the system, 

 and we have been very slightly inconvenienced by their action 

 on our ordinary senses. But it may happen also that our 

 ordinary senses have perceived nothing at all, whilst illness* 

 elevation, or depression of some kind, which are modes by 

 which we feel a chemical action, prove it to have taken place. 



The air of our towns generally seems to waver between 

 these two states ; in some cases it is shewn to be hurtful by 

 our ordinary senses, in others it can only be felt in a secondary 

 manner, or by what it is fairer to call our chemical senses. Of 

 course I leave out here the fact that it is almost at all times 

 visible to the eye, but there are differences of opinion as to the 

 effect of that portion which is visible. 



At the same time it must not be forgotten that there are 

 advantages in towns which cannot be obtained out of them 

 by the most of people^-dryness caused by good drainage, 

 and the cleanness of good sewerage. 



As I said before, I have nothing which I can call actually 

 new to bring forward here, but it does still present some 

 novel feature. The air was not examined as such, because I 

 had not proper conveniences for the experiments, and I was 



