FARM SANITATION 



535 



Size of Inlets and Outlets. Professor King advises four 

 square feet each of outtake and intake flues for each 20 adult 

 cows, for an outlet flue 20 feet high; or, in other words, 36 

 square inches of cross-section of flue should be provided for 

 each cow. If the outlet flue be 30 feet high, 30 square inches 

 of cross -section will be sufficient. To be successful, there 

 should be a rather large number of intakes and few out- 

 takes. The outtakes should be air-tight, as straight as pos- 

 sible, and as smooth as practical on the inside. One common 

 cause of failure of this system of 

 ventilation is incorrectly con- 

 structed outtakes or outlet flues. 

 Often the flues are made of one 

 thickness of tongued and grooved 

 lumber which dries out and leaves 

 open cracks which prevent the flues 

 from working. Again, it is a com- 

 mon occurrence to find that the 

 flues are made with many sharp 



turns Which restrict the flow Of 

 air through them. A gOOd CUpola, 



so designed as to produce a suction 



on the flues connecting into it when the wind is blowing, 



increases the efficiency of the system materially. 



Mechanical Ventilation. Mechanical ventilation is prac- 

 tically unknown at the present time for farm buildings. It 

 consists in providing fans or other positive means of forcing 

 air into or out of a building, and is considered the only 

 modern method of ventilation. The time may come when 

 it will be considered in connection with farm buildings. All 

 other systems depend more or less upon varying conditions of 

 wind and temperature, which cannot be controlled. 



Fig. 323 Different methods 

 of arranging the Inlet flues in 

 the King system of ventila- 



