LIVE STOCK breeders' ASSOCIATION. ' 203 



each animal acts upon the air of the stable, heating it, enabhng it to 

 rise to and accumulate at the ceiling where, if it is sufficiently tight, it 

 is retained, heating the ceiling, which then comes to act exactly like 

 a heated radiator sending its warmth back upon the animals upon the 

 floor, thus keeping the stable at a higher temperature than would be 

 possible were the warmed air permitted to escape all at once at the 

 ceiling. Now to utilize the heat accumulated at the ceiling of the 

 stable to the best advantage, the fresh, pure, cold air must be 

 brought in at the level of the ceiling and caused to mingle with it 

 as completely as possible, so as to be warmed by it before it drops to the 

 level where the animals use it. To secure this, provision is made for 

 the fresh air to come into the stable at a considerable number of 

 small openings just under the ceiling on as many sides of the barn as 

 practicable, as represented by the arrows in Fig. i. 



In order to prevent the warm air escaping at the ceiling through 

 these intakes, they must be carried downward by some construction so 

 that the air is forced to enter them at some level on the outside four 

 or more feet below the level on the inside, as represented in Fig. 2. 

 When this construction is adopted it acts on the principle of an air 

 trap, for the warm air of the stable cannot readily pass downward. 



A suitable size for these intakes is 4 or 5 inches by 14 or 16 

 inches, the long axis being horizontal. They should be placed at 

 every 9 to 12 feet along the wall and be provided with lids hinged on 

 the lower edge so as to regulate the amount of air entering the stable, 

 deflecting it upward to the ceiling and causing it to fan out and dis- 

 tribute well through the warm air of the stable. It is particularly im- 

 portant that these fresh air intakes be placed on every side of the 

 stable in order to take advantage of the wind pressure to aid in forcing 

 the ventilation. It is important to recognize that there are three im- 

 portant factors or forces, each of which should be brought into requi- 

 sition to the fullest extent possible in maintaining the air movement 

 through the stable. These are (i) the wind pressure against the side 

 of the building, which tends to drive air into the stable through any 

 openings on the windward side ; this increases the pressure of the air 

 in the stable and so forces it to flow out and up through the ventilating 

 flue. (2) The wind in passing up and along the roof sweeps with in- 

 creased force across the top of the ventilator, as it does across a chim- 

 ney, producing an outward suction, thus reinforcing the wind pressure 

 on the side of the building. (3) Whatever rise in temperature the air 

 of the stable experiences, making it warmer than the mean of the air 

 outside, causes the column in the ventilation shaft to be, lighter than 

 a corresponding column outside, and hence it is forced upward and out 



