108 DEW OF THE BREATH. 



Now, as the temperature of health is very con- 

 siderably above the average of that of the air in tem- 

 perate countries, and indeed above the average of 

 almost any country, it follows that the expired 

 breath, which, as has been said, is loaded with the 

 superfluous moisture of the body, must have a ten- 

 dency to produce dew upon the colder air against 

 which it is breathed. In dry and warm states of 

 the atmosphere that dew is not observable, though 

 even then the breath will stain a mirror, if held near ; 

 but when the atmosphere is cold or moist, the breath 

 of man and of all the warm blooded animals be- 

 comes visible; and in keen frosts, a man's own 

 breath will cover his hair with hoar frost, and even 

 form ice upon his face. But the same heated moist- 

 ure of the breath which becomes apparent in those 

 cases exists in every case, whether circumstances 

 render it visible or not, and thus it becomes a pro- 

 tection against draughts or currents of air. These 

 blow the warm and moist breath against the face ; 

 and that instead of parching it, as the common air 

 would do, dews gently upon it, and protects it from 

 injury. The effect is much greater than one would 

 suppose ; for if one stand with the head bare when 

 the wind blows keenly, one can bear it longest by 

 facing it. It is not a little curious that the danger 

 of catching cold should, like all other dangers, be 

 greatly diminished by being faced. 



The mists, or dews, which are formed in the 

 higher regions of the atmosphere, are of a very dif- 

 ferent character from those that are formed on or 

 near the surface of the earth. The earth-mist, as 

 we may call the lower one, before it can rise up- 

 ward in the air, and disturb the state of things 

 there, has the resistance both of gravitation and co- 

 hesion to overcome ; whereas, the descent of a mist 

 or cloud, formed in the upper part of the sky, has 

 both of those resistances as powers acting in favour 

 of its descent. That consideration helps to explain 



