56 STABLE ECdNOMY 



stances which produce motion in the air. To leave the inlet 

 to chance, is just as much as to say that it is of no conse- 

 quence in what direction the fresh air is admitted, or whether 

 any be admitted. The outlets may also serve as inlets ; but 

 then, they must be much larger than I have mentioned, and 

 the stable, without having purer air, must be cool, or sold. 

 When the external atmosphere is colder than that in the stable, 

 it enters at the bottom of the door, or it passes through the 

 lowest apertures to supply and fill the place of that which is 

 escaping from the high apertures. If there be no low open- 

 ings the cooler air will enter from above ; it will form a cur- 

 rent inward at the sides, while the warmer air forms another 

 current, setting outward at the centre of each aperture. But 

 when the upper apertures are of small size, this will not take 

 place till the air inside becomes very warm or hot. 



The stables at the Veterinary College are all single-headed. 

 Each stall has an aperture at top of the head wall for car- 

 rying off the foul air, and in the back wall there is another 

 of the same size, level with the ground, for admitting pure 

 air. These are covered with iron-grating to exclude vermin. 

 This, I think, is not the best place to have these inletting 

 apertures. In order to reach the. nostrils, or head of the 

 stall, where the impure air is rising upward, the fresh air 

 must pass over the horse's heels while he is standing, and 

 over a great part of his body while lying. The same thing 

 happens when it passes from the bottom of the door. A cur- 

 rent of cold air is established, and constantly flowing from 

 the point where it enters, to the point where it escapes, and 

 the horse, or some part of him, stands in its path. Possibly 

 a current so small and so feeble may do no harm, but possibly 

 also it may have something to do in the production of cold 

 legs, cracked heels, or an attack of inflammation. If it have 

 any effect it can not be of a beneficial tendency, and ought 

 therefore to be prevented if it can be prevented. It is easy 

 to break the current and diffuse the cold air over the stable, 

 by placing a board or some other obstacle opposite the inlet- 

 ting apertures. It would be better, however, if they could 

 be placed nearer the points where the air is wanted. 



In Mr. Lyon's stables (Fig. 7) there are no apertures pur- 

 posely contrived for admitting fresh air. The windows serve 

 both as outlets and as inlets. They are very large. While 

 the warm and impure air is ascending the sides of the tunnel, 

 the external air is descending the centre of the same passage, 

 and spreading over all the stable. This keeps it cool, cooler 



