58 STABLE ECONOMY 



former times, it was supposed that they were necessary for 

 taking out the carbonic acid gas formed during respiration. It 

 was found that this gas is much heavier than common air, and 

 it was imagined that it fell to the ground, like water when 

 dropped among oil. But it is now known that, though heav- 

 ier, the gas unites with the atmosphere, or gravitates in very 

 small quantities, and only till the air can absorb it. 



When the floor of the stable is bad, retaining the urine and 

 then rejecting it by evaporation, the inlets and the outlets re- 

 quire to be much larger than I have mentioned. A low roof 

 also renders large apertures very necessary. 



Objections urged against Ventilation. — These, as I have 

 already hinted, often have their origin in ignorance, which 

 attempts ventilation without knowing its intention or the mode 

 of producing it ; and in indifference, which thinks it does 

 well while it follows as others have led. The cost of ven- 

 tilating a stable is very trifling, yet some are so awkwardly 

 arranged that the process may demand more than the owner 

 is willing to give. It is the most foolish of all objections ; 

 the evils produced by bad air may be attended with more loss 

 in six months than would pay the cost of ventilating the 

 stables six times. Even where there is no actual disease, the 

 horses, if doing work, require more corn to maintain their 

 condition than those who have more air. 



The cold currents of a ventilated stable, to which people 

 so often object, are injurious only when the apertures are too 

 large or improperly placed. If there be a large aperture be- 

 hind the horse's heels, and another above his head, the cold 

 air must pass over him, and in force proportioned to its vol- 

 ume. But this is easily avoided, either by having a number 

 of very small apertures, or by placing the outlets and the in- 

 lets in such relation to each other, that the horse can not 

 stand in the way of the current. The told air is always 

 flowing by the nearest road from the point at which it enters 

 to the point at which it is consumed, that is, at the horse's 

 nostrils. With a knowledge of this simple fact, to which I 

 have already alluded more fully, ventilation may be so regu- 

 lated that the current need not traverse much of the stable, to 

 cool the air, nor to fall on any particular part of the horse. 

 When the fresh air must pass over the horse, before it can 

 reach his nostrils, its force can be broken by admitting it 

 through numerous and wide-spread perforations, each perhaps 

 not exceeding half an inch in diameter, but taken altogether, 

 nearly equal in size to the aperture by which the foul air 

 escapes. 



