LECTUKE XXII 

 VENTILATION 



Purposes. — There are several purposes in ventilation; viz., 

 getting fresh air with its oxygen into a stable, getting impuri- 

 ties of various kinds out of the stable, regulating temperature, 

 and controlling moisture. 



Impurities. — The common impurities of air are : disease germs 

 and their products, dust, carbon dioxid and other gases. Ex- 

 cess heat and moisture in a stable, while not impurities, are very 

 objectionable. 



Stable air. — One good authority (F. Smith) reports analyses 

 of air for European stables. These are, of course, variable, but 



Fig. 37. — Ventilation. 

 Outlet with too many angles. 



(Paige.) 



Cow receiving inlet air from over a 

 manure pile. 



Smith's figures give a good general statement. The average of 

 28 analyses gave .14 per cent carbonic gas (C0 2 ). In another 

 series of 28 analyses he found an average of .21 per cent. In 

 recent American work, Clarkson and Smith found .25 per cent 

 C0 2 as an average of 6 tests in a well ventilated stable. In an- 

 other stable with still better ventilation, they found .14 per cent 

 as the average of 6 tests. For a normal outside air we may take 



about .03 per cent CO £ . 



109 



