VENTILATION OF STABLES. 53 



Modes of Ventilating Stables. — Many people are perfectly 

 aware that their stables ought to be aired ; but they are igno 

 rant of the mode in which it should be done. The owner 

 or groom is told that the stable is too close ; and he replies, 

 "The stable is not so close as you think ; indeed, it is rather 

 cold if anything. This window is generally open all day, 

 and that hole is never closed. I got it made on purpose to 

 air the stable, for it was too hot before." Now, it frequently 

 happens that the stable is not too warm, and that the hole and 

 the window do keep it cool. But this is not to the purpose. 

 These people can not be made to understand the difference 

 between warm air and foul air. They are always thinking 

 and talking of the temperature, when it is the purity of the 

 atmosphere that ought to engage their attention. Ventilation 

 may be managed in such a way as to preserve the air in toler- 

 able purity, without making it uncomfortably cold. There 

 must be apertures for taking away that which has been 

 vitiated, and apertures for admitting a fresh supply ; and 

 these must be properly placed. Their situation is of some 

 consequence, particularly when it is desirable to kee,p the 

 stable warm. In general they are placed too far from the 

 roof, too near the ground, perhaps about a foot above the 

 horse's head. In this place, they must be so large, in order 

 to air the stable, that they must also cool it. 



When the impure air escapes from the horse's lungs, it is 

 warmer than the surrounding air, and it is lighter. In con- 

 sequence, it rises upward. It ascends to the highest part of 

 the building ; if permitted to escape there, it does no harm. 

 When there is no aperture so high up, the air remains at the 

 roof till it becomes cooler, or cold. When cool as that which 

 occupies the lower part of the stable, or when cooler — and it 

 soon loses its heat — the air descends, and is rebreathed a 

 second, a third, or an indefinite number of times, until it be- 

 comes perfectly saturated with impurities, or exhausted of its 

 oxygen — at least comparatively exhausted — unable to supply 

 the demand. Then a part of the blood must pass through 

 the lungs without undergoing the usual change, and the horse 

 becomes less vigorous, and consumes more food and more 

 water than he would if the air were purer. There may be 

 large openings in the stable capable of admitting fresh air, yet 

 they are of no use unless there be others for letting out the 

 impure air before it cools. 



Apertures for the Escape of the Impure Air, ought to be a* 

 the highest part of the building, or as near to it as possible 



5* 



