70 VETERINARY HYGIENE 



window in the wall over the head of each animal, the 

 windows being pivoted and not of the Sheringham valve 

 type just described.* 



With windows fully open to windward, opposite ones 

 closed, and ridge open (Fig. 6) the air rushes in, carries all 

 before it, then spreads out fan-shape and falls to the 

 ground. If the incoming current be powerful it may be 

 measured 18 feet from the point of entry, but as a rule 

 6 feet to 8 feet is the distance at which it can be felt, the 

 velocity rapidly and suddenly decreasing on meeting with 

 the large body of air already in the stable. 



The tendency of the incoming air is to spread and fall 



Fig. 6. — Direction taken by air currents with the windows open to 

 windward. 



fan-shaped to the ground, and in so doing it drives before 

 it the air previously there, until this is forced upwards 

 and escapes by the ridge on the leeward side. 



If the incoming current be powerful, part of it may 

 escape at the ridge on the leeward side without mixing with 

 the lower stratum of air, while the windward side of the 

 ridge may act as an inlet. 



No currents can be detected under the open window, the 

 velocity with which they enter carries them practically 

 clear of the horse standing there. 



When opposite windows are open (Fig. 7) the air rushes 



* At the time these observations were made, no building fitted with 

 Sheringham windows was available, but this does not affect the 

 general principles here described. 



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