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rentilation could ever do. A common standard by which the effective- 

 ness of a system is judged is its ability to keep the walls and ceiling 

 free from moisture. This is frequently a most unfair test. Precipi- 

 tation of moisture on walls or ceiling is due to the warm vaponir or 

 water-charged exhalations of the animals, rising and lying for too 

 great a length of time in contact with the cold wall or ceiling as 

 the case may be. If the construction of wall or ceiling be faulty, as 

 for instance, where only double boards with paper between constitute 

 the same, then no system of ventilation could keep them dry without 

 lowering the inside temperature to practically the same as the outside. 

 Walls possible of being kept fairly dry must have more or less 

 insulation, that is, a dead-air space or a concrete core, or shavings, 

 or something to prevent too rapid conduction of heat. Then with 

 a fairly rapid circulation of air the walls and ceiling may be kept 

 dry. A ceiling protected by straw or hay overhead is the most 

 satisfactory. 



Walls with a dead-air space may usually be kept dry fairly 

 easily. Stone walls or solid cement walls must be lined to insure 

 their being fairly dry. No system of ventilation would otherwise 

 ever keep them dry in very cold weather. 



The number of cattle in a given cubic space is quite an important 

 factor making for the effectiveness of any system. Too many cattle 

 makes it difficult to ventilate in such a way as to avoid draughts, 

 too few makes it impossible to keep the temperature up to the com- 

 fortable point and at the same time provide for sufficient air circula- 

 tion. Low temperature does not always mean pure air, and here 

 is a point where a great many stablemen make a mistake. The air 

 in a stable where the thermometer shows several degrees of frost 

 may quite easily be most vile. From all which, it seems important, 

 in the first place to so arrange matters that there shall be about the 

 right number of animals in the given stable, allowing, say, from 600 

 to 800 cubic feet of air space for each cow two years old and over. 

 This condition existing, there should then be provided about 15 square 

 inches or more of controlled outlet area and about 8 square inches 

 or more of controlled inlet area for each animal in the stable. For 

 instance, a stable 36 x 30 x 10, which might be expected to accomo- 

 date 18 or 20 head, should have an outlet about 18 inches square or 

 20 inches in diameter, if round, and the inlets should be at least 6 

 inches by 12 inches and two in number. 



