282 



CANADIAN FARM YEAR BOOK. 



temperature and cause the ventilators 

 to work, and this in proportion to the 

 requirements. The greater the num- 

 ber of animals and the closer the 

 stable, the more rapidly will the sys- 

 tem operate. And this is what is 

 needed, not only for puritx of air, 

 but for uniformity of temperature as 

 well. In a close stable, the degree of 

 foulness of atmosphere corresponds 

 with the temperature, as both are 

 directly influenced by the radiation 

 and breath from the stock. The air 

 warmed by the stock naturally rises 

 and seeks an outlet. The outlet is 

 necessarily at the ceiling and consists 

 of a flue which passes through the 

 roof. At the Experimental Farm, the 

 flues pass through an upper story. 

 These should extend well above the 

 building for the same reason that a 

 chimney must do so in order to draw 

 well. 



The inlets enter the stable at the 

 floor level. The inlet pipe is U- 

 shaped and passes beneath the foun- 

 dation wall. If the fresh air is taken 

 from a covered shed, the mouth out- 

 side may be near the ground level, 

 and be protected by a grating. If 



Dehorning Stall For Cattle. 



however, the air has to be drawn 

 from outside, more especially in dis- 

 tricts subject to snow fall, the pipe 

 should extend 4 or 5 feet above 

 ground and the opening should be 

 roofed so as to avoid the entrance of 

 snow or rain, or undue influence from 

 the wind. The roofed pipe is built 

 against the wall, and the air enters 

 through slots in the sides close 

 against the building. The size ot 

 these openings corresponds with the 

 capacity of the pipe inside. 



The ventilator works by virtue of 

 the natural tendency of warm air to 

 rise. As the air warms, it becomes 

 foul, rises and escapes by the otuiets. 

 As nature abhors a vacuum, the es- 

 cape of the warm air creates a suc- 

 tion of fresh air by way of the inlet 

 pipes. Since the animals are con- 

 stantly giving off warmth and expell- 

 ing carbonic acid gas, the warm, foul 

 air is constantly escaping and cold, 

 fresh air is at the same time entering 

 the stable, thus keeping \xv a gentle, 

 almost imperceptible, system of ven- 

 tilation. To regulate the ventilation, 

 a damper is provided in the outlet 

 flue. The closing of this also stops a 

 large extent the inflow of fresh air, as 

 the draught ceases, stopping the suc- 

 tion. By the original system, the in- 

 let pipe enters at the floor level. This 

 is to facilitate a steady, unobstructed, 

 almost imperceptible flow of ait 

 through the stable towards the out- 

 lets. To guard against chaff, and 

 dust falling into the opening, Mr. 

 "Grisdale, in the main cattle barn at 

 the Farm raised the openings about 

 four inches above the floor level. 



The amount of ventilation neces- 

 sary for a barn depends upon thd 

 number of animals to be housed. Suf- 

 ficient is needed to maintain in cold 

 weather a temperature of from 40 to 

 45 degrees Fahrenheit. A well-built 

 stable, stocked to a reasonable capa- 

 city, should have the air changed 

 every 30 to 45 minutes. Air removed 

 at this rate will carry off the foul 

 air as it is expelled from the stock; 

 it will also remove the vapour which, 

 if allowed to remain, would condense 

 on the walls and ceilings. 



The intake and outlet flues should 

 be about the some In capacity that is, 

 provided the stable is tightly con- 

 structed. Because more or less air 

 is sure to enter around windows and 

 doors, the intakes may be slightly 



