LECTURE XXVIII. 

 VENTILATION CONTINUED. 



Amount of ventilation needed. — The horse passes 45 cubic 

 feet of air through the lungs per hour. This, then, would be 

 the amount which the average horse would use if he were out 

 in the open where the supply is inexhaustible. It is impossi- 

 ble to have the air of any occupied stable as pure as the out- 

 side atmosphere. The purpose of ventilation is to come as near 

 to this point as may be feasible. 



It has been estimated that the air should not be changed 

 more than six times per hour in cool weather, on account of 

 drafts which more frequent change would produce, and the loss 

 of animal heat. 



Air passing at the rate of three miles per hour, which is 

 barely perceptible, through an opening one foot square, admits 

 15,840 cubic feet per hour. 



STABLE CONSTRUCTION. 



Space needed. — A large cubic space per animal is important, 

 but this does not lessen the necessity for ventilation. The at- 

 mosphere in a large stable with a given number of animals may 

 become just as foul as a smaller stable with the same number 

 of animals, the only difference being in the length of time re- 

 quired to reach this condition. The chief value in a large amount 

 of space is that it gives the possibility of admitting a sufficient 

 amount of air without such severe drafts, as would necessarily 

 be the result of admitting the same amount of air per hour into 

 a smaller stable. 



Location. — In order that a stable may be well lighted and 

 well ventilated it is necessary to have considerable care in se- 

 lecting the location and planning the proportions of the build- 

 ing. One of the most desirable forms is that of a main part 

 standing east and west and used in a general way for storing 



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