LECTURE 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. {Paige.) 



Outlet witli too many angles. 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 (CO,). 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 

 CO2 as an average of 6 tests in a well ventilated stable. In an- 

 other stable witli 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 



