[Illustration: FIG. 21. CONTINUED.]
The system of ventilation is the "King." To economize space and lumber,
the hay chute is used for a ventilator. This chute, which extends to the
cupola, is 2-1/4 x 3-1/2 feet, having a cross section area of 8 sq. ft.,
which, with a good draft, is sufficient for 40 cows. In order that this
combination of ventilator and hay chute prove practical, doors thru
which the hay could be thrust were placed at intervals in the side of
the chute. These doors are hinged at the top, opening in, and close
immediately after the hay drops, thus maintaining a closed ventilator
chute. The air is drawn in at the bottom, the amount being regulated by
means of a sliding door in the side. As this chute is 50 feet high, it
creates a strong suction.