114 



CAUSES AND PREVENTION OF DISEASE. 



purposes with one or two "ells" at right angles to this on the 

 south. This arrangement makes possible a very satisfactory and 

 well protected yard on the south side, and gives an even lighting 

 to the various portions of the "ells" in which the animals are 

 kept. It will be readily seen that when a stable extends east and 

 west, and is wide enough for two rows of stalls, the animals on 

 the north side do not get much light, for the general lighting of 

 their portion of the stable is poor. 



Width. — A stable to be capable of the best ventilation should 

 not be over 25 to 30 feet in width. And the lower the better within 

 limits, when one is depending on natural conditions. 



FIG. 43. VENTILATION. (PAKIE.) 



Air duct obstructed by cobwebs Stationary outlet cowl to utilize the 



and dust. force of the wind for producing up- 



ward suction, and to prevent down 

 draft. 



Windows. — In order to secure suitable ventilation in a build- 

 ing of tliis kind two sets of windows should be provided, at least 

 one set on each side. And better two sets on each side. Doors 

 and windows should be opposite, i. e., door opposite door and 

 window opposite window wherever practicable. 



It can be stated in a general way that where one is depend- 

 ing upon natural ventilation, and the air is brought in cold, that 

 the inlet should be low and the outlet high; but this does not 

 imply that the stable need be very high. 



Shafts and tubes. — In considering ventilation by shafts and 

 tubes, it should be remembered that circular, straight tubes are 

 preferable, and as for outlets, the shorter the better. It is esti- 

 mated that a right angle bend in an outlet diminishes the velocity 

 of the outgoing air about one-half. Where it is absolutely nee- 



