VENTILATION. 



Ill 



Diffusion of gases. — Carljunic gas is considerably heavier 

 than air and the lower levels usually contain a slightly higher 

 percentage than the higher ones in a stable, but the difference 

 is not so great as one would suppose, on account of the diffu- 

 sion which takes place in response to the law of diffusion of 

 gases — which operates independently of relative weights. This 

 force is so strong in its action that considerable diffusion takes 

 place through impainted lumber and through ordinary brick, but 

 to a very slight extent if at all through painted surfaces or pa- 

 per. 



AIR CURRENTS. 



An entering current of air has the effect of inducing other 

 currents within the stable the induced current setting in at right 

 angles to the inlet current. 



i 





y/ 



vVV 



FIG. 42. 

 Air currents. 



VENTILATION. {PAIQE.) 



Manger front inlet. 



With windows wnde open to windward, openings on the 

 other side of the stable being closed, and with ridge ventilation — 

 it is found that the current of air rushes in, strikes the floor 

 at a variable distance after spreading out somewhat, then rises 

 and most of it passes out at the ridge. A current decreases 

 very rapidly in velocity after the first five or six feet from the 

 inlet. The atmosphere immediately under the inlet is but mod- 

 erately disturbed. 



When opposite windows are fully open the air comes in 

 from the windward side, strikes the ground, rises again and a 

 considerable portion passes directly out at the opposite side. 



