410 



THE CLIMATE OF IRELAND, AND 



dry, it would seem at first sight that the chilling effect should be 

 less also. But this is more than compensated by the increased con- 

 ducting power of air when charged with moisture. When such air 

 is much below the temperature of the body itself, the heat of the 

 latter will escape through it, much more rapidly than through air 

 that is dry. The chilling effect of the damp fogs of winter, with 

 all their train of attendant evils, is due to this cause. 



On the other hand, extreme dryness of the air produces an in- 

 jurious effect of a different kind. When the air in contact with 

 the lungs is excessively dry, inflammation of the organ is apt to 

 ensue ; and thus, to those who have a constitutional tendency to 

 such disease, a very dry air is often fatal. To this cause are to 

 be ascribed the painful, and even fatal effects of the simoom, the 

 dry wind of the African desert. And it is on this account also 

 that, in rooms heated by iron stoves, which are so common in 

 Germany, a vessel containing water is usually placed at the top 

 of the stove, to give the suitable degree of moisture to the air. 



The mortality in towns is much greater than in the rural 

 districts adjoining. Thus in Belgium, where vital statistics have 

 been collected with much care, the death-rate in the towns is 27 

 per 1000, while in the country it is only 21. This is in part 

 accounted for by the deficiency of pure air produced by over-crowd- 

 ing. Every adult inhales about 13 cubic feet of air in an hour, 

 from which his lungs extract the vital element, and replace it by a 

 noxious gas ; and in populous cities and especially in the dwell- 

 ings of the poor this waste is not adequately supplied.* The 

 effects of overcrowding have been clearly shown by Dr. Farr, in 

 his useful analysis of the Eeports of the Eegistrar-general on the 

 mortality of London. The following are the results of his com- 

 parison of the mortality with the density of the population, in the 

 three principal districts : 



It has only lately been brought to light, by the philanthropic exertions of the 



