The foul a.\r escapes through an outlet ventilator H, in the ceiling 

 (one opposite to each inlet ventilator), placed close to the back wall, 

 thence into a horizontal air flue j, which runs along the floor of the hay 

 chamber, to collect the air from all the outlet ventilators, and finally 

 passes out at the roof through a large vertical shaft K, terminating in a 

 roof ventilator L, so constructed that the action of the wind always 

 causes an upward current in the shaft. The vertical shaft may rise from 

 any part of the horizontal one, and it enables the ventilator to be placed 

 in the centre of the roof, or, for a large building, two or more may be 

 used and spaced at any intervals required for architectural effect. 



The advantages of this system will now be seen. The fresh air 

 enters near the ceiling by the inlet ventilator a, driving before it the 

 breathed air from the horses, which passes out directly at the roof, but 

 no cold air can fall upon the horse either from the inlet or outlet opening. 

 Even on a close summer day there will be a sensible change of air in a 

 stable thus ventilated, because a slight up ward current is induced by the roof 

 ventilator in the calmest weather, and the heated breath from the horses 

 will of itself pass away so long as it is guarded against a down draught. 



